It is hard to comment on the flow of articles on the topic of “preparation for a blackout”, which started in all kinds of media in mid-October due to the beginning of Russian shelling of the energy infrastructure of Ukraine. On the one hand, the demand for information about everything related to off-grid sources of electricity unexpectedly exploded in our society. So a niche topic that until February 24, 2022 was of interest only to “survivalists” and “green energy workers” became relevant for millions of citizens. And hysterical demand awakens hysterical supply – and outright fraudsters, dubious do-it-yourselfers, and just clout chasers.
The author is not an electrician. And if a certain system requires professional intervention, it is strongly recommended to contact professionals. But 20 years of testing various computer hardware and ten years of suburban life in conditions where the power often disappears taught me something even before the war. And the number of conversations about all of this recently simply requires me to express my thoughts in text form and stop repeating the same thing… For the sake of academic clarity of the presentation, I would like to separate the main outline of the material from examples of specific calculations and all kinds of advice and useful details, but then the integrity of the narrative is lost.
The idyll of energy independence with solar panels, generators and powerful charging stations in the Ecoflow promotional photo
This article does not replace the entire array of reviews, tests and guides for buyers of all described devices and only offers to develop a specific view of them, corresponding to the challenges of war in 2022. Things are different in peacetime. Unfortunately, right at the time of publication of the article, there is a strong demand on the Ukrainian market for everything listed below, and prices have risen noticeably, sometimes several times, from pre-war prices. And of course, if a certain offer looks too good to be true, it probably is.
Attention! The article truthfully describes the author’s own experience, as well as the results of observations and research that brought the desired result. With all that, the material is written exclusively for educational purposes. The author does not guarantee success and is not responsible for errors of the performer or misinterpreted text. Do not attempt to follow these instructions without the necessary knowledge and skill level (including working with tools). Safety equipment is above all else. Good luck!
Basic concepts of electrical engineering
If you feel that your understanding of the meaning of the words “Volt”, “Ampere”, “Watt”, “Watt-hour” and their interdependencies is already a bit blurry since you’ve studied school physics, don’t hesitate to ask Google. Reminding yourself of these basics will help you understand the topic much better going forward and possibly avoid costly mistakes. A fairly systematic approach would be to read the main articles listed in the section “Electrical engineering” in Wikipedia.
Step Zero: Preparation
When planning your energy independence, first of all, you need to understand the situation as a whole. In peacetime, this is not very relevant, but now, before even starting calculations for autonomy longer than one day, think about everything you need, except for electricity: water, food, heat, medicine, transport, communication, money and everything else on same time period! How will the social systems you rely on work? Because a month’s supply of fuel for a generator by itself is of little use if there is no source of water and heat in the winter. Or in a charged smartphone, if there is no power on the mobile tower.
Great book “Don’t panic! How to survive, fight and win during combat” in electronic form is now available for free download from the website of the publishing house “Astrolabia”. It helped the author to prepare morally and materially for the beginning of the invasion on February 24, but there are many other sources of similar information. Read, plan, and remember that energy independence is not the goal in itself — the goal is to survive (preferably comfortably) in extraordinary conditions, war or no war…
Food, matches, lighter with fuel, gas cylinder (with a stove), paper notebook with pen, toilet paper, knife, flashlight, radio, batteries for everything… This is something that will be 100% more relevant than “energy independence”. Depending on the length of the period for which the preparation will take place, the stock of cigarettes and alcohol can be considered as currency, and not for personal consumption. If the household already owns a legal firearm, it must be fully ready for use, including sufficient ammunition. All this and many more important details of the preparation of civilians for combat operations can be learned from the most important element in the photo — the book “Don’t panic!”, the electronic version of which is now distributed by the publishing house “Astrolabia” for free.
P.S. The author couldn’t help but put a gift from the Armed Forces of Ukraine in the still life, namely a trophy pack of Business Class cigarettes, taken from a Russian somewhere in the summer in the South.
First, you need to understand your needs: which devices to power, what is their capacity, and for what period of battery life is the system designed for: several hours, a day, a week, a month or more?In the simplest cases, you can probably do such an “audit” in your head, but even in an average apartment it will be easier to write out critical consumers in a separate list and thus visualize your needs.
There are three unpleasant surprises waiting here:
- There may be more devices than expected. The absolute minimum is to charge your smartphone. But if you calculate the energy independence of a private house, it is dozens of consumers. That is why it is better to mark them in a list, because that way it will be clearer what was forgotten, and to think about how to optimize.
- Power is not always obvious. At most, for our purposes it is calculated in different ways: typical, starting, average over a period of time… In ordinary life, most people think about power consumption only in terms of the monthly electricity bill – and there is not often some catastrophic amount to worry about. But even the minimum 100 kW per month, if they cannot be simply taken from the network, will become a serious challenge for the organization of independent energy supply!
- The desired period of off-grid operation will require a large power supply capacity. This is a direct consequence of the first two points. This is especially important for battery operation. Going a little further, here is a clear example: if the average consumption of a household per hour is only 200 W (refrigerator, router, TV and/or laptop, a couple of lamps), then a typical in the eyes of car owners 12 V 60 A battery will be enough for one and a half to two hours, depending on how lucky you are with its condition and the characteristics of the inverter! After that, it will require charging from a 220 V network for at least 6-10 hours, depending on the charger and the state of the battery. And it will withstand several hundreds of such cycles at best, and more likely several dozen…
Unfortunately, there are no magic remedies and this should become the main idea of the entire article: every decision has its own price, pluses and minuses, which should be known and accepted, and not hoped to bypass.
The question of energy in general has been one of the main ones for humanity since at least the beginning of the industrial revolution, so that for centuries entire branches of science and industry have been fighting over improvements in this area. And this is not a stamp of bad journalism, but the literal state of affairs: there is technological progress, the fruits of which benefit the entire civilization, and there is an actual price of this progress, which is measured in money for each decision. There is no masonic conspiracy or cartel conspiracy here, just pure physics and economics. That is, if for UAH 800 from OLX or for UAH 500 from Aliexpress you could buy a real power bank with a capacity of 30,000 mAh and a weight of 200 grams, this would mean that battery developers have magically learned to make them three times easier and cheaper than was possible a month ago. And the reality is that the scammers in anabsoultely unmagical way put the desired characteristics on a product that does not meet them and a simple test will reveal a capacity of 10,000 mAh at best… The same applies to any attempt to cheat the system in the energy industry – no clickbait article will give the “silver bullet” recipe, because if such existed, it would already be used in serial solutions of large corporations.
A collage of satellite images of the night lighting of Kyiv in January and November 2022 reminds us why we need energy independence
That doesn’t mean there aren’t improvements. Vice versa. LED lighting saves a staggering 80% compared to incandescent bulbs, so there’s even a government program to replace them now to reduce overall grid consumption. Another example: the latest LiFePO4 batteries are three times lighter than their lead predecessors, charge five times faster, have almost no discharge over time, have almost no memory effect and withstand five times more discharge cycles. Magic? A person from the year 2000 would say yes, but now these are normal market solutions that do not cost much more than the older ones. It’s just not a secret in the style of clickbait “take the old Soviet…”.
And the return to the real world must begin with an audit of existing consumers. For most appliances, you can find official specifications to get an idea of what to expect, but this is not a very reliable way. The best investment here will be at least one smart outlet that informs about the current load and calculates consumption per day through the application. The author uses RZTK Chic with the Smart Life Android application, but this not fundamental. The main thing is that it is possible to see real indicators of devices, not passport ones. Because this is the only way you can truly establish, for example, that an air conditioner as a heater instantly consumes 500-600 W, but to maintain a temperature of +20 degrees in a specific room at “near zero” from the outside, it needs 8 kW of electricity per day of operation – that is, 333 Wh on average, and not the 500-600 W from an “instant” calculation… Similarly, for 24 hours of operation, a refrigerator side-by-side consumes almost exactly 1 kW, although the instantaneous consumption is about 100 W, not counting the starting peak.. But these are the data of the author’s specific devices, the knowledge of which allows him to clearly plan his own energy independence. And in other conditions, on devices of other manufacturers and other models, all similar calculations will be different! Readers of Mezha should understand this well from reviews of processors and video cards, where PC consumption is measured and it is different depending on the configuration. That is why it is so useful to have a smart outlet.
However, for the most general understanding, such an infographic prepared by the Telegram channel will suffice UA War Infographics based on data from Yasno:
In general, all electrical appliances for the purposes of this material can be divided into three categories.
- Anything that runs on direct current and therefore has its own power supply with some conversion of 220V into what the appliance needs: phone, router, PC with monitor, TV, audio system, LED lighting…
Firstly, most of such devices are simply quite economical (up to tens, not hundreds of W/h), so they can be used for a long time during a blackout.
Secondly, they often have a stable consumption from the mains, so it is easy to calculate the operating time from a battery source (if a 50-inch TV consumes 100 Wh, then you can expect from a battery with a practical capacity of 1 kWh, it will work for about 10 hours).
Thirdly, thanks to the existing transformation of the input voltage by the power supply unit into a much smaller direct current (usually from 5 to 20 V), many devices of this type work calmly in the range of the mains voltage 100-240 V. Why this may be important is explained further in the section on charging stations. In addition, many such devices can be powered directly from themains, if the source outputs 5 V (for example, via USB), or 12 V — so there will be less conversion loss in the process.
- Something that works directly from alternating current without having powerful electric motors: stove, coffee maker, boiler, microwave oven, iron, heaters…
Such consumers are characterized by much higher consumption, up to several kilowatts. But often they are turned on for a short time – for example, it is more logical to count the energy independence of a coffee maker not in hours, but in the number of coffee preparation cycles. And a boiler that heated water for an hour and spent 2 kW on it can continue to keep it hot enough even for a day. However, the high instantaneous power consumption of such devices means that work from an inexpensive battery source will be measured in minutes, not hours, and this is in the case that the inverter or generator has enough capacity to withstand the load from even one consumer.
- Electrical appliances with motors: various pumps, refrigerators, air conditioners, washing machines…
The most difficult type of devices to calculate due to the fact that, in addition to constant consumption, the starting current of the motor, which is several times higher than the typical one, is important for them. It creates a short, but high load on the power source (and it is so short that household smart sockets do not have time to show it, so they are not suitable for calculation). Manufacturers of inverters and generators take this into account, indicating “peak power” in addition to the nominal one – that is, the mode in which the device will still work with a permissible overload, but only for a short period of time, until the consumer’s electric motor starts. Accordingly, if, after turning on a typical generator or inverter, you simultaneously start, say, a pump in a well, a pump of a heating system and a refrigerator, then their total starting current will “knock out” the protection against peak overload, although according to their nominal consumption, they will all fit into the nominal the power of the source! The solution is simple – turn on the existing devices with motors not simultaneously, but gradually (manually or with the help of a switch). But even in this case, in the conditions of an independent energy source, you will have to save and calculate the use of such devices.
A wise illustration from Bluetti – how much you can practically use their various products before discharge: something in hours, something in quantity, so you can see more clearly.
After the list of critical consumers is drawn up and their real power is calculated including the starting current – two of the three “unpleasant surprises” mentioned above cease to be surprises and you can start realistically planning energy independence, thus dealing with the third surprise in the form of the price of the desired capacity solution. Because there will be as much autonomy as the buyer is willing to pay for! So you may have to find compromises or alternative solutions within the limits of common sense and safety. For example, do not turn on the washing machine at all during a blackout, set the refrigerator to a mode like “for 4 hours of operation every 16 hours”, buy a gas stove for cooking, and switch the heating of a private house to gas or solid fuel (even taking into account the costs of new equipment, stocking up on firewood, coal, or gas cylinders for the season may be easier than building an all-electric system that can make it through the winter in standalone mode).
Ecoflow Delta Pro and powering different consumers: the advertising picture draws green lines, but reality needs wires…
By the way, in the preparation process, the connection method should also be taken into account – how exactly to supply power from the source to all consumers? For example, gadgets can easily be connected to a portable charging station, but what about lighting or a well pump? And if the emergency source will power the entire existing electrical system of the apartment or house, how to turn off all non-critical devices from it every time so that there is no excess consumption? Or is it important for autonomy how much is collectively consumed in stand-by mode by all numerous devices that are simply plugged into sockets 24 hours a day when they are not working? It is better to have answers to these questions for yourself before spending money on energy-independent solutions.
Finally, as they say “last but not the least” – be sure to buy a large fire extinguisher (for home use and for electrical appliances — preferably carbon dioxide, not powder). In general, even in normal times, it should be in every home literally “just in case of a fire”, but any experiments with electricity supply increase the risk many times over. So, first the fire extinguisher – then everything else!
The first step: power banks and batteries
Otherwise, this step can be called “how to live without 220 V”. Most people are familiar with power banks since the times of peaceful life. Usually, their capacity is measured in milliampere-hours, which is useful for comparison with the capacity of a smartphone battery. In theory, a power bank with a capacity of 20,000 mAh should fully charge a phone with a 5,000 mAh battery 4 times, but in practice it turns out to be somewhat less. And this is normal, because all devices have an efficiency of less than 100%. To convert Milliamp-hours to Watt-hours for a transparent assessment of a power bank’s ability to power something other than a phone, the calculation is simple: 5V (USB voltage) * 20000 mA⋅h (typical power bank capacity) = 100 Wh. Accordingly, under ideal conditions, a 10-watt consumer will work for 10 hours.
It is not normal when a power bank with a capacity of 20,000 mAh manages to charge a phone, say, only 1 time – this will mean that the real capacity is much less than the declared one. Unfortunately, this will most likely mean that the manufacturer simply lied. Moreover, it will be possible to check only with the experience of full charge-discharge, and not with a quick inspection at the post office. This is an unpleasant, but typical practice for nameless Chinese factories that are ready to order a separate product and a separate sticker with specifications. And this is the first reminder that there are no magic solutions in the field of energy! It is obvious how to protect yourself from such techno fraud: buy goods of proven brands from proven sellers at the expected price. Suspicious ads on OLX and super offers from Aliexpress will most likely bring disappointment – although, of course, there are quality products on these trading platforms, just without “magic”.
The power bank from Baseus charges three devices at once, while the total power is 22.5 W, and the capacity is 30000 mAh
In addition to capacity, the power bank has two important characteristics: power and voltage. And there is no magic here either.
A power bank with a capacity of 10 W (that is, a typical current for phone chargers of 2 A through a 5-volt connector) will be able to gradually give energy to a switched-off laptop through the USB-C port, but will not be able to power it during operation, because the consumption will be greater than the power of the source! Moreover, it will not be able to power, say, a 20-watt light bulb at all, even if it has the appropriate voltage. For this, there are power banks with support for the USB Power Delivery standard, which can have a power of up to 100 W (only, of course, some “Chinese manufacturers” can lie here – buy products from proven manufacturers from proven sellers!).
The typical voltage coming through USB is 5 V, but the Power Delivery standard also allows 9, 12 and 20 V. Some power banks have additional connectors, for example, 12 V and even provide for use as a starting device for a car. It used to bother a few people, but now another “clickbait” topic has appeared – powering a WiFi router from a power bank so that the Internet works when the power is turned off. There are several problems here.
First of all, for it to make sense at all, energy independence must be supported by the provider itself (those using fiber optic cables are more likely to work during a blackout). Secondly, it is necessary to measure the power of the router, and sometimes also of a separate modem, and compare it with the capacity and power of the power bank. Primitive routers, by the way, will be more economical than the “gamer” monsters with a dozen antennas, which are loved by reviewers, so maybe it makes sense to buy an even weaker router! Third, the voltage… Routers usually require 9 or 12 V (this data is on the power supply sold in the kit) and do not have a USB connector, so you will need an adapter to connect the power bank.
Dell Power Bank Plus can deliver up to 65 W of power
A regular power bank is an adequate power source for a smartphone, tablet, router, and possibly a laptop. And also useful, power-wise, for anything else that plugs into USB or runs on 5V — like e-cigarettes, some light bulbs, or battery-powered flashlights. The main issue will be to have time to charge them when you have power in the network, because the same typical 2-amp charger will work from the network for 10 hours to “fill” a power bank with a capacity of 20,000 mAh. Therefore, it is advisable to look for options with the fastest possible charging (and it should be supported by both the power bank itself and the actual charger).
There can’t be many many flashlights, and their selection is a separate topic. But for home use, the main thing is to have enough batteries of the right type in stock. By the way, the radio receiver, which is compatible with large battery-type flashlights, also has its own small flashlight just in case.
The first consumption optimization is lighting. There is a flashlight in every smartphone, but it is too weak for many tasks and at the same time quickly drains the battery, which must be recharged from an endless power bank. So it’s good to have at least one regular self-powered flashlight. And buy as large a stock of non-rechargable batteries as the budget allows. Choosing a flashlight for different purposes is definitely a topic for a separate article, but in everyday life almost anything will do, only without a rechargable battery, because this returns to the problem of charging it without a network at all and the speed with which the battery will allow it to be done. As for indoor lighting, there are many LED solutions that connect to USB and, accordingly, can be powered by a power bank without problems.
Another battery-powered item that needs to be purchased now is an AM/FM radio (also with spare batteries if they are a different format than the flashlight). The Single telethon may seem to Ukrainians to be an ironically slow method of obtaining information compared to Telegram channels, but in the absence of the Internet, this will be enough to be informed about the general situation around, and even for some entertainment.
It will be useful to audit (again) everything that is powered by batteries and buy all types in a certain quantity. However, this advice is useful at any time.
Reading the Book of Cain from Diablo III by the light of a petroleum lamp was particularly atmospheric
Finally, candles provide enough light compared to no light at all without consuming any electricity. Together with a radio receiver, it can be the last method in case of a long blackout, or maybe just a means of saving batteries or a power bank – after all, it’s quite romantic and stylish. Of course, with compliance with fire safety. A petroleum lamp is brighter than several candles and more economical in terms of money, but it is even more dangerous and creates a specific smell.
Second step: battery systems
The transition from a “power bank” to a “charging station” is imperceptible, it is more of a marketing issue, and the “uninterruptible power supply” adds to the schematic diagram only its own fast automatic switching from the mains to the battery. But the popularity and availability of typical power banks, nevertheless, demanded that they be carried out as a separate first step together with batteries and candles, at least based on the logic that they do not provide 220 V, and the second step to energy independence is the creation of a backup source of exactly 220 V.
The scheme of all systems using a battery is the same:
– the actual battery of a certain voltage and capacity ensures the storage of electricity
– the charger ensures the supply of electricity from some other source to the battery with the required voltage and current
– an almost always present inverter allows you to receive energy from the battery with a different voltage than is provided by the battery characteristics (more often: 5, 12, 110 or 220 V).
Anything with a battery as a source would fall under this description:
– power bank
– computer UPS
– UPS for the boiler
– Ecoflow charging station
– battery with inverter and charger
– hybrid inverter with battery assembly
Their essence is the same – to store electricity from another source on the battery and give it away when this source is not available. That is why it is very popular to offer Ecoflow charging stations as an alternative to a generator, until the appearance of the terrible term “electric generator”. Because such a system does not generate anything by itself, but only gives away what has been accumulated. However, of course, they have their benefits, so you should consider all battery options that are more solid than a power bank.
Advertising collage reminds of the range of UPS from APC
Computer UPS are probably the best known to the audience of Mezha. In the last decade, in connection with the growing popularity of laptops and tablets as home PCs, they have become noticeably fewer, but they are still on the market. The most useful function is the uninterrupted power supply itself, that is, an instant switch to the battery if the voltage in the network drops below a certain level or, on the contrary, increases. It also protects the equipment from harmful power surges. But for the purposes of energy independence, ordinary computer UPSs are almost not suitable, because a typical internal lead battery has a capacity of 9 A⋅h at 12 V and, accordingly, all continuity will end in 20-30 minutes even with a consumption of 100 W.
In addition, UPS often have something like an eco mode, which will generally limit the operating time not by battery discharge, but by a timer. The next charge takes, on average, 10 hours — too long in conditions of fan outages. Moreover, if it is relatively easy to modify the UPS to connect a large battery of “car” size (of course, this will lead to the loss of the warranty and, in general, it is done at your own risk), then the charging speed will be a problem without a solution. Another relatively small inconvenience — not all computer UPSs have ordinary 220-volt Schuko-type sockets as outputs, often instead they use connectors C13 (socket) and C14 (plug), as on ATX standard power supplies. So to connect something else, you will need a “C14/Schuko” adapter. Of course, powerful UPS of the “server” level, where the capacity is measured in kilowatt-hours, can be used for any other equipment, but such devices, to put it mildly, are atypical for a Ukrainian household.
The old MGE Nova 600 AVR computer UPS needed an extension cord with a C14 plug to connect household consumers
But what is typical is “UPS for boiler“. As usual, with terminals for connecting a large battery (50-200 A) and better charging (10-25 A) than in the “computer” versions. Their popular name arose because of the most popular use. When the light goes out, the gas or solid fuel boiler of the heating system would continue to work, but an electric pump is needed to pump liquid through the pipes and batteries, and if it is turned off, not only will there be no heat, but the boiler itself can overheat and go out of order.
In addition to the power and large capacity of the battery, “Boiler UPS” is also known by the phrase “perfect sine wave”. This is a characteristic of the form of the current, which, in this case, is issued at the output of the inverter, and 100% ensures the compatibility of the source with the power supply of the electric motors. Modern gas boilers are especially legendary in this matter, where, in addition to the pump itself, there is also a safety automatic – and its operation does not allow the boiler to be started without a “perfect sinus” at all.
Then the house remains without heating – that is why there is such a specific demand in the market! Other consumers, including pumps for solid fuel boilers, are less picky about the shape of the current, although there is a semi-mystical opinion that the equipment will work longer. An inverter capable of producing current the correct shape is more expensive to manufacture, so the device itself (actually an inverter or UPS) with a correct sine wave turns out to be much more expensive. And the corresponding battery is not cheap. This encourages adventurous users to build complex systems for boilers from a computer UPS, an old Soviet (literally!) stabilizer for a tube TV and a starter battery. It turns out differently… In general, if you choose the battery and the power of the UPS itself correctly, then this very source would be optimal for “moderate battery energy independence somewhat cheaper than Ecoflow”, if there was not such a shortage of any UPS on the market now. But the charging time of an ordinary battery is not long, we will talk about that a little later.
Ecoflow product line
What are now called “charging stations” (often referring to the most famous brands – Ecoflow and Bluetti) are basically no different from “UPS for a boiler”. It is also a battery, charger and inverter with the perfect sine wave. Simply, all components are clearly selected for specific usage models, in a beautiful case, with a smartphone application and with a high-quality positioning in the market.
They are fundamentally distinguished from power banks by the presence of a 220 V socket, in addition to USB and 12 V. The marketing revolution of the approach to the battery power source as a fashionable gadget was offered by the Chinese manufacturer Ecoflow, and all others, including the Americans Bluetti, have already moved into a new niche. A detailed review of product lines, advantages and disadvantages of Ecoflow and Bluetti should be considered in a separate material, preferably with tests. In principle, when choosing, you should look at the ratio of power with capacity, price and the only technical point: “LiFePO4 battery or not?”. If the work has already been done and the capacity of the consumers and the desired time of their operation are known, the choice will be obvious in any class. The presence of a LiFePO4 battery in particular cannot be overestimated — it allows you to charge the device much faster, which is now a critical parameter.
For the largest Bluetti stations, even with the maximum configuration of additional batteries, it is quite logical to connect to the entire energy system of the house — will be extended both in terms of power and capacity
It should be emphasized once again that there are two separate parameters of the charging station: power (in Watts) and capacity (in Watt-hours). The first is responsible for how powerful consumers can be connected to the device in total. And the second — for how much consumers will be able to work before discharge. For example:
- If the power of the station is declared to be 200 W, and the capacity is 800 Wh, then connecting an 800-watt microwave oven will not work at all, one 100-watt TV will work 8 hours, and two such TVs – 4 hours (it will not work to turn on the third).
- If the power is 800 W, but the capacity is 100 Wh, then the microwave can be connected, although it will work for 8 minutes, one TV will work for 1 hour, and two – half an hour (and you can turn on at least 8 such units, but with a proportional decrease in the working time).
Solar panel as a source of slow but Ecoflow Delta charge where there is no network (and even where there will not be)
As a rule, charging stations have several ways to charge them and several ways to release energy. The connector for the solar panel is standard, so it is not necessary to buy a branded panel – it is enough to choose one with the necessary parameters. The capabilities of solar charging declared by the manufacturer are very optimistic, but this must be confirmed by testing. It is not necessary to expect that even a small Ecoflow will easily charge from the panel that was displayed on the windowsill of a high-rise building in December in Kyiv. Most likely, it will not charge at all. But on the beach in the summer it can do it in a day. Somehow. Charging from the network is another matter. There shouldn’t be any problems here, especially for models with LiFePO4. Car charging from the “cigarette lighter” (in reality, from any 12-volt battery, not necessarily installed in the car) and 5-volt from USB are also available, but the charging speed will be limited compared to the 220 V network.
Regarding ways of charging, everything is simple here: there is USB (ie 5V DC), there is a “cigarette lighter” (ie 12V DC) and there are regular outlets 110 or 220 V of alternating current. If this is possible, consumers should be connected to direct current – for example, charging a smartphone directly from USB, and not by connecting a charger to a 220 V outlet, in order to avoid losses due to unnecessary conversions of current and voltage.
Something like this…
Be careful if you plan to buy the cheaper American versions: they are designed for a 110 V network, which leads to two unpleasant consequences.
Firstly, it is impossible to charge from the Ukrainian 220 V network without an additional 220 inverter -> 110 V. Such inverters are commercially available, but will add price to the solution, especially those powerful enough for larger versions of charging stations. If there is no inverter, then all the slower options with direct current (USB, 12 V, solar panel) remain.
Secondly, it will be impossible to power those consumers that require exactly 220 V, and not a wide range of 100-240 V – for example, a pump, coffee maker or microwave oven. If these are not planned, for example, the station is taken exclusively for charging gadgets, LED lighting and powering a router or Starlink, then there will be no problem. Theoretically, even in this case a 110->220V inverter or plugging a 12->220V inverter into the cigarette lighter socket will help, but this is a very inefficient way, and the additional inverter will cost a fraction of the price difference between the US and “normal” European version of it same as Ecoflow.
Another “how long will it work” calculation – this time from Ecoflow for a monumental configuration of two Delta Pros, two additional batteries and two generators – with a total capacity of 25 kW· h, but also at a total price of more than $10,000 in the USA…
Interesting fact: charging stations are produced almost exclusively by start-ups. Well-known names in the industry, in addition to Ecoflow and Bluetti, are Anker and Jackery, but there are half a dozen other brands and many Chinese names. While the 4 listed manufacturers definitely produce goods of the expected quality, how honestly all the others treat their duties is a debatable question. So it will not be surprising if an attempt to save money and take some “Aliexpress Special” will be unsuccessful — say, the device will take a long time to charge, quickly discharge and will not keep the promised power.
One very important point is related to connecting the source to consumers. Of course, you can connect a triple adapter or an extension cord to the built-in Ecoflow socket and power several devices through it – the main thing is that their total power does not exceed the standard one. But connecting the entire apartment using the “socket to socket” method is a violation of all possible safety standards! Even if you turn off the supply from the network “on the register”, there is still a chance of an error that will surely kill the charging station. If you already want to power the entire apartment or house from the battery system, it should be done according to the generator connection scheme, that is, with a three-position reserve input switch. And preferably, it should be installed by a professional electrician.
A small Bluetti charging station that powers several consumers at the same time within the limits of the total capacity
If you do not take into account speculative prices in Ukraine, such charging stations are an ideal solution for consumers who want a plug-and-play solution without the need to understand the specifications of chargers, batteries and inverters. And control through the application adds modernity. And after the war, they will work for tourist purposes.
The fact that branded charging stations do not carry anything fundamentally new in the design became the basis for a whole movement of enthusiasts “to assemble Ecoflow with your own hands” and, accordingly, very popular materials on this topic. We note again – in there are no secrets to energy that can be bypassed at home! If you put aside the beautiful case and branded application, then any Ecoflow is a battery+charger+inverter. All these three components are known, at least to drivers. The battery is in every car, the charger for it is often in the garage for emergencies, and the 12-220 V inverter with a cigarette lighter socket is familiar to those who at least once wanted to charge a laptop in the car… But the idea that separately from the car these three components will work perfectly at home, replacing the expensive Ecoflow almost for free – is wrong in most cases. The devil is in the details: which battery, which charger, which inverter? They can be chosen as needed, and the chance that a car battery will fit is minimal.
Let’s start with the battery. The following are important here: voltage, material, type (starting or traction), capacity and deep discharge support.
A normal car has a voltage of 12 V, a motorcycle can be 6 V, and trucks have 24 V. Of course, by series connection, the voltage can be made multiple times higher – for example, for home systems popular batteries at 48 V, which is achieved by connecting 4 batteries of 12 V in series. The higher the voltage on the battery side, the weaker the current required to power a 220-volt consumer and vice versa for charging from the network. This reduces the requirements for the thickness of the wires and improves fire safety, because they heat up less (and heating, by the way, is a clear manifestation of efficiency losses!). As a result, a 48V 200A assembly of eight batteries is much better than a 12V 800A configuration of the same eight batteries. After all, it can be charged with a current of 50 A (50*48=1900 W, which is possible for a regular 220 V outlet or an average generator) in 4 hours, not 16. And when connecting a 1200-watt consumer, the current to the inverter will be at the level of 25 Ah, not cosmic 100 A… And higher efficiency due to lower resistance losses in the system.
The AGM battery can be charged indoors
Battery material is not that important in automotive use – the simplest lead-acid batteries work perfectly for 5 years or more. More advanced gel and AGM are installed by car manufacturers “because they can”, and not because it is vitally necessary. The installation of lithium-ion (Li-Ion) and lithium-iron-phosphate (LFP, or LiFePO4) batteries as starter batteries in the automotive industry seldom happens, although such materials are used for electric vehicle batteries because they are lighter and charge faster.
Everything is the opposite at home! Lead batteries of computer UPS are sealed, but typical car batteries are not. When charging, they emit harmful gases, which does not cause problems under the hood, but will do in a small living room. If you already have a desire to experiment with a lead battery, then you need to charge it exclusively in the fresh air – this is not a whim, but a categorical requirement of safety! All others (AGM, gel, lithium) can be charged indoors. In addition, they have better rates of charge-discharge cycles, which is not very relevant for a car, where the battery ideally does not discharge strongly at all, because it is supported by the generator. And they can be charged faster, because lead batteries have a limit of no more than 10% capacity per hour. However, lead ones have an advantage: they can be serviced, thereby extending their service life. More advanced types of batteries simply last longer, but do not allow the user to look inside.
Small (8 A⋅h), but traction battery from a computer UPS. Since it is sealed, it can be charged at home even despite its lead-acid construction
The division into starting and traction batteries arose from the need to turn the starter in the car – a very powerful motor, at the start of which the battery must produce a short-term current at the level of 500-1000 A. If you transfer 12 V and 1000 A to Watts, then in output is 12 kW, i.e. 16.3 hp. The ability to do this (for which they are called “starters”) is the opposite of a battery’s ability to run longer at a lower steady state, such as powering a small boat’s electric motor. Accumulators that work better with stable consumption are called “traction”. Of course, for use in a power source for the home, it is the traction type that is better, only it is 2-3 times more expensive than the starter of the same nominal capacity.
Illustration from articles on the website of the battery manufacturer Renogy, which explains several important things: the non-linear dependence of the charge percentage on the battery voltage; the difference in the characteristics of lead-acid, AGM and LiFePO4 batteries (including deep cycle) and the fact that none of them can be discharged “to zero”.
The typical capacity of a car battery is 60 A⋅h. If you translate this mathematically into watt-hours, you get 720 Wh. But in practice, it will be good to get half of this. And very rarely do they support deep discharge, i.e. the regular ability of the battery to discharge “to zero”, after which it is normally charged to 100%, as phone and laptop batteries do. In the absence of a specialized charger, an ordinary starting lead battery can “die” even after one such deep cycle… Traction batteries almost always support a deep discharge, so they give a significantly higher percentage of the declared capacity. Markings on lead, gel and AGM batteries usually correspond to reality, but lithium batteries, especially on Aliexpress, exist, so to speak, separately from the inscriptions on them and the capacity declared by the seller. A simple example: if the battery costs like a 100-amp battery and weighs like a 100-amp battery (11-12 kg for LiFePO, which is three times lighter than lead!) – then it will work like that, even if the manufacturer puts the marking “250” on it. Because there is no magic in energy.
From the author’s experiments with various 12-volt batteries, the following picture emerged of the real “useful capacity” when connecting a 130-watt 220-volt consumer through a small inverter (with a real power of about 200 watts):
– Starter lead-acid 60 A was able to give 250 Wh;
– Starter 105 A of AGM type with deep discharge support – 650 Wh;
– Traction “250 A” (actually 100 A) LiFePO4 – 1000 Wh.
Simba cat monitors the testing process of a LiFePO4 battery with a UKC “500 Watt” inverter and a 130W electric blanket
With significantly higher consumption (say 500 Wh via another inverter) the measured “useful capacity” would be slightly lower due to higher losses. And with a significantly smaller one (say, 10 Wh and some small inverter) – it would be possible to “squeeze out” somewhat better indicators in watt-hours. But something in between is looming. As a result, by the way, you can draw the following parallel:
– The most affordable Ecoflow/Bluetti charging stations with their capacity of 250-300 Wh are approximately similar to a set of a Chinese inverter and a 60-amp starter battery
– “Big little” Ecoflow/Bluetti (550-750 Wh) are similar to a system based on a high-quality traction gel/AGM battery 100 A and an inverter, which is already on the border of reasonable power for a 12-volt system
– Older series of the Ecoflow Delta type with a capacity from 1000 to 4000 Wh are already in direct competition with “wall” systems based on a hybrid inverter and a 24/48-volt battery pack
But this is all until you start comparing charging speed, ease of use, and everything else, which should be discussed in a separate article.
In a charger the important things are: voltage, current, ability to work with specific battery material.
The voltage is obvious – it just has to match the characteristic of the battery or their collection (for example, two 12-volt batteries connected in series can be charged with a 24-volt charger, but not each of them separately).
This typical Bosch car battery is a lead-acid battery. Therefore, its charging must be carried out either in the open air, or with good ventilation, or at least in a garage where there are no people during this process.
The value of the current has also been partially described above. Here, too, the charging and battery capacities must match. Overcharging kills any battery, but for lead-acid the norm will be 5-10 A (10% of the nominal capacity), for gel – 15-30 A (30%), and for LiFePO4 – up to 50 A. On the other hand, chronic undercharging can “kill” a gel or AGM battery. There will be nothing wrong with charging with a current of 2 A in itself, but if every time when the lights are turned off for 4 hours, the 100-amp battery is discharged by half, and in the next 4 hours you have time to charge only 8 A⋅h, then it will not only discharge completely for several cycles, and will also lose a greater percentage of the resource than with a normal charge to 100% each time.
This is what special programs of the charger, adapted to specific types of batteries, should prevent. Their presence is not critical for simply being able to charge the battery, but it will affect long-term operation or the ability to “resuscitate” a completely discharged battery.
Charging a serial LiFePO4 battery from Aliexpress using a complete charger. Pay attention to the labeling – there is not a hint of 250 A⋅h: both in terms of weight, price, and behavior, this is a normal 100-amp battery, no more and no less. “There is no magic!”
With the charging of lithium (Li-Ion and LiFePO4) batteries there are other specifics. They consist of a large number of batteries of lower voltage and capacity, for example, 3.2 V. Each such battery must be charged evenly with the others, otherwise the cells will begin to fail. The BMS board (Battery Management System) is responsible for this. In normal ready-made solutions, it is necessarily on the side of the battery, that is, it is enough to simply connect a charger that is suitable for power and voltage. But if some suspicious battery is bought separately (for example, converted from an electric car), then it is far from a fact that the BMS is already there or that this unit is made correctly. Be careful!
Also, the charger sometimes has the ability to calculate the battery percentage. Unfortunately, only ready-made charging stations provide an accuracy similar to the accuracy of such an indicator in a phone or laptop, because the manufacturer knows all the characteristics of the battery from the beginning and can adjust the calculation algorithm. This is another point where “there is no magic in energy” – without accurate input data, there will be no accurate output. For example, when charging a car battery, it is better to calculate the charging power in amperes and divide the battery capacity by it. It will not be absolutely accurate, but a realistic calculation of hours until full charge, unlike a certain indicator in percentages on the charger…
In inverter the important things are: input and output voltage, power, peak power.
Input (12/24/48 V) and output (110/220 V) voltage should simply be matched to your conditions – which are batteries and consumers. Moreover, regarding the existence of 110-volt inverters for America, this is just a reminder of a possible failure in an attempt to save money on orders in the USA. The presence of an additional USB connector on the inverter simplifies the power supply and charging of the corresponding devices, because the efficiency without conversion to alternating current will be higher. By the way, if the “12-volt” battery produced strictly 12 V, then certain consumers could be powered directly. But the operating voltage range of a car battery is somewhere between 10.5 and 14.5 V, which can be too varied for, say, a router with exactly 12 V. Therefore, you should not experiment with direct power without an inverter, unless you know for sure, what you are doing.
One of the simplest inverters is the UKC SSK-500W, with a declared power of 500 W (but, in practice, about 50% of it). It used to cost nothing and the author had it for years in his car to sometimes power his laptop. And now it is actively used at home, and the price tag on the market for the same inverters has increased fivefold…
The power of the inverter, of course, is responsible for the ability to connect certain consumers. And the peak power is for compatibility with those devices that have a higher starting current. So, it is precisely these indicators that are abused by manufacturers and sellers. Another example that there is no magic in energy: a $50 inverter the size of two packs of cigarettes definitely cannot produce 1000 watts of power. In addition, with a realistic efficiency of 85%, it will convert 150 W of them into heat, which requires sufficient cooling! For those who are familiar with computer power supplies, it will be enough to remember the price, dimensions, weight and coolers of a 1000-watt BZ with a similar purpose and compare all this with a suspicious inverter that is now sold for three times the price on OLX or cheaply on Aliexpress.
The bigger the numbers on the device, the more monumental it should be. Also, let’s say a fair 2000W of consumption by a 220V device from a 12V battery would require it to deliver a current above 200A given the efficiency of the inverter. Not only is this beyond the capabilities of a typical battery, it also requires very thick wires. And even in the best case, a traction battery with a capacity of 100 A⋅h will work like this for 30 minutes, and it’s good if it can make it to only 20… As for the peak power, the optimistic statements of nameless manufacturers lead to frustration like: “I cheaply bought an inverter for 4000 Watts of peak power, and it won’t start my pumping station, even though it says 850 watts.” Because in fact, the inverter likely has 2000 peak watts, and the pump has 3000 watts of starting consumption…
Energy independence at a glance from what was at hand: charging from the garage, batteries from cars and boats, an “optimistically 1000-watt” inverter…
Summing up. Typical car battery: 12 V, lead-acid, starter, 60 A⋅h. It has a 5-10 amp charger and an honest 200-500 W inverter. It can give about 300 Wh and will charge for 10 hours after that, and it should be done outdoors. It can withstand up to a hundred (rather, less) such cycles. All operations, such as the start and end of charging, the start and end of power from the battery, must be done manually, switching terminals. Does all this look like “cheap homemade Ecoflow River”? Not much, other than pure capacity. However, if such simple ingredients are available, then for a certain level of energy independence they can also be used – because it is better than nothing… And after all the calculations, and even more so my own experiments, instead of Kulibin’s audacity, there should be more respect for manufacturers of serial charging stations that work in accordance with all the declared characteristics, are easily transported and also have a guarantee.
The hybrid solar inverter produced by the Chinese company Must illustrates the general scheme of all such systems. Without solar panels, the scheme works perfectly on batteries, where the inverter acts as a charging device from the network or generator.
And what would be the ideal battery system for the home? Battery for 48 V, LiFePO4, traction, 100+ A⋅h. With a 50 A charger and an honest 3-5 kW inverter. The capacity is from 4800 Wh and higher, and charging should take 2-4 hours, and with daily use it will last for several years. The system powers the entire wiring of the house or apartment, automatically switching to batteries when the light goes out and, conversely, charging the batteries at every opportunity to obtain energy from the network. Is this possible? Yes, this is the description of the largest Ecoflow Delta Pro charging station with an additional battery. And also — a typical system with a hybrid inverter, which combines an inverter, a charger, and a UPS.
At most, it will be 2/3 of the finished autonomous solar electricity stations, because only the 3-5 kW panels will need to be added to the scheme. And the bad news here is only in the price of the solution — it will be measured in thousands of dollars. By the way, such systems from separate components will be cheaper than similar top models Ecoflow or Bluetti, primarily because they are much more stationary. And the apotheosis of branded options is the Tesla Powerwall. And in this case, using a high-quality hybrid inverter and a battery assembly, nothing prevents you from outdoing Elon Musk by making a “cheap self-made Powerwall.” Well, of course, not literally cheap, but it is much cheaper to reproduce the characteristics of the system on your own, simply without marketing and without the support of a well-known manufacturer. Because again, there is no magic in energy, only money for solutions that work.
Tesla Powerwall. Unlike Starlink, there is nothing innovative about this device.
Regardless of whether it is a power bank or a Powerwall, the use of a battery system requires a change of perspective on consumption. After all, the system only stores energy, and does not generate it, so this final resource will have to be saved, albeit on different scales depending on the system. Common sense in this matter will help energy independence more than accepting one’s own preliminary calculations of consumption as dogma. For example, a PC with an additional monitor is used for work. Can this work be done on a laptop? It may be inconvenient, but if you compare 1 hour of PC operation from batteries with, say, a week of working time recharging a laptop, the answer is obvious. If you watch the movie on a tablet, and not on a TV, the savings will be similar.
By the way, another benefit of a smart outlet: if you enable the setting to not supply current to the consumer after the power is restored, then you can cheaply and automatically solve the problem of turning on large appliances from an autonomous sources. Let’s say the boiler should work from the mains, but when the light goes out and the system goes to the battery or generator – to turn on the boiler, you will need to turn on the outlet first (with a button or through the application). Thus, there will be no unpleasant surprise that the boiler “devoured” half of the battery’s capacity in an hour… Similarly, you can delay the start of devices with a noticeable starting current.
Step Three: Generator
According to the name, the generator itself “generates”, that is, it produces electricity, which fundamentally differs from all battery systems, which can only store what they received from another source. Put simply, the generator consists of an internal combustion engine that spins the generator itself, which supplies 12 or 220 V to consumers either directly or through an inverter.
A typical generator, in this case from Briggs & Stratton
Without an inverter in the design, the generator does not produce “zero”, only “phases”, from which the required voltage is formed. This leads to a conflict with some equipment (including long-suffering automated gas heating boilers). By the way, in a generator without an inverter, the sinusoid is always perfect, so the issue of powering a capricious boiler is solved in a different way – a separate “zero” is created in the system, but this should be done by professional electricians. The inverter generator is able to provide ideal power, plus additional control options appear (up to smart models with an application), but the design becomes more expensive and limited by the power of the inverter.
From the point of view of electrical capabilities, the same two characteristics are important for a generator as for an inverter – power and peak power. Usually, household generators have a power of 2000 to 6000 W, and the peak power is 20-30% more. There are smaller models, starting at 500 watts, and there are much larger models for tens or even hundreds of kilowatts, but these are not home solutions.
Due to their small dimensions and relatively low noise, inverter generators are also called tourist generators.
The issue of capacity is specific. The generator needs fuel to operate, usually gasoline, gas, or diesel. They are also finite, but it is incomparably easier to make a supply of liquid fuel for a month than to make a battery system that will work for the same amount of time.
Consumption depends on the power, but in a non-linear way: somewhere up to 50% load, any generator consumes almost as much as “running idle” – about 2/3 of the maximum value. And this leads to an important consequence, which is easier to illustrate with an example:
- A 3 kW generator from running idle to 1.5 kW load consumes approximately 0.7 l/h. The maximum consumption will be at the level of about 1.2 l/h.
- A generator with a capacity of 5.5 kW from running idle and up to 2.5 kW of load consumes 1.5 l/h. The maximum consumption will be at the level of 2.2 l/h.
Thus, if the entire home system, already optimized for energy independence, powered by a generator, consumes an average of 300 Wh (refrigerator, pump, lighting, computer with a router), then both generators will work in almost “idle” mode, while differing in consumption twice. That is, the first on 100 liters of reserve will last (100/0.7)=142 hours, and the second — only (100/1.5)=67 hours! Of course, if there is a need to sometimes turn on some powerful consumer at all 5 kW, then it is necessary to either install the larger of the two generators, or, if the budget allows, take two smaller ones for “energy independence”.
A corner of invincibility in the author’s garage: a supply of gasoline for the generator and gas for the convector.
The verdict is simple: the power of the generator must correspond to the real needs, calculated for a specific case, it will be economically unprofitable to take it “for future use”. The bad decision is large diesel generators of 20-30 kW, which “in rich times” were bought for a private house “because we can” – there the minimum consumption reaches 10 l/h, even if the consumption is the same 200-300 W·h It is very expensive and ineffective. In addition, if you calculate the maximum endurance, then there is the question of fuel storage: 100 liters in canisters is easier and safer to store than 1000…
The fact that an ordinary generator from 0 to 50% load already consumes almost the same amount of fuel leads to an interesting effect – instead of consciously saving every Watt, you can turn on more consumers than usual! For example, feel free to add a 1200 W electric boiler to the next 300 Wh – this way the “extra” kilowatts turn into some benefit for the home. Inverter generators can be able to reduce the operating speed of the engine in the absence of a noticeable load, and thereby save fuel and consume less resources.
Generators have two more limits on uninterrupted power supply — the capacity of the fuel tank and the actual allowable time of operation without a break for cooling. For safety reasons, you can add fuel only when the generator is turned off and has cooled down, so if the tank has a volume of 20 liters and the generator consumes 2 liters per hour, then after 10 hours there will be a natural break. But in most household generators there is also a recommendation or even a requirement from the manufacturer to turn it off for at least 30 minutes every 4-5 hours of operation, if you want the device to work for the warranty period. Large diesel generators can work much longer, even around the clock.
Changing the oil is a mandatory ritual every 50 engine hours!
Most generators on the market are gasoline. It is important that ordinary A95 should be poured there, not alcohol versions (marked as A95-E). There are serial gas/gasoline solutions, even in Ecoflow – these can be safely powered from a gas cylinder. Kits for independent converting of gasoline generator to work on gas also exist, as do autogas systems for cars, but that would be out of warranty. Even more risky and beyond the limits of safe use — conversion for power from a gas pipe… As for diesel, the real meaning appears at a power above 10 kW, because then their efficiency, reliability and economy really reveal themselves. But in the “domestic” class, the main advantage of a diesel engine is just the fact that it is an alternative fuel.
Unfortunately, any generator imposes a lot of requirements regarding its operation. It is similar to a car, or, more precisely, something like a lawnmower:
- Deadly poisonous exhaust
- High level of noise and vibration
- Places of local heating of the device itself are fire hazard
- Fuel is a fire hazard, and you need a lot of it all the time
- Mandatory replacement of lubricant (typically every 50 engine hours), glow plug, air filter
State Emergency Service reminds of danger!
All this does not cause big problems in a private house with a plot, but it makes it very difficult to operate the generator in the conditions of an apartment, especially compared to some kind of Ecoflow, the presence of which in the household does not need to be reported to anyone and to explain something Of course, from the impasse in 2022, Ukrainians began to find methods — take it to the roof, buy one generator for several apartments, take small inverter models and hang them outside the window (like an air conditioner), often categorically violating safety rules. We hope that this will not lead to a lot of accidents…
As with everything else, today’s super demand for generators in Ukraine has caused a wave of offers of low-quality goods at inflated prices. And if the price tag is regulated by the market, you just have to accept it, then it is the buyer’s task to protect yourself from bad goods. As always, “there is no magic in energy”.
Historically, the numbers in the model name are perceived as the declared power in watts, at least peak, but the new trend is to indicate, for example, “8500” in the name, but from the numbers on the body we see it is a typical 2-3 kilowatt generator. If the buyer made a decision based only on those numbers, that’s his problem. But there are worse manipulations, when the power is overestimated in the characteristics and, say, a 3-kilowatt model is passed off as a 5-kilowatt one. How to notice it:
- By engine power in horsepower. It cannot be less than the declared peak output power, because this violates the laws of physics;
- According to the declared maximum current, which when multiplied by the output voltage will be less than the promised power;
- The easiest: by weight. Generators from different manufacturers are structurally the same, so if you suspect that the chosen model does not live up to its promises, compare its weight with official data on similar models from well-known manufacturers such as Hyundai or Endress.
Even in the advertising collages of the smallest (13 kW) diesel generator models, Caterpillar hints at industrial rather than domestic use .
In addition to power, voltage and number of phases are important. It’s good that they don’t cheat here anymore. It makes sense to take models for 380 V only to power real three-phase consumers of the corresponding capacity. In most cases, even when the household has three phases, a single-phase 220-volt generator is sufficient, which is distributed to all three phases. Of course, the total power does not change, but if necessary, each phase will be able to use its entire reserve, and not one third.
The presence of an electric starter is a big plus, because it is much more convenient to start with a key than with muscle power. Moreover, the manual starter will still be on the generator in case the battery dies. And a fully automatic input of the reserve, when in the event of a network failure, the generator is started and connected by itself is rather a bad thing for domestic models, because from the point of view of engine life and fuel consumption, it is better to make your own decision when to start and turn off the generator. By the way, you need to think carefully about the alarm that the light has appeared in the network in order to turn it off in time.
The engine resource of a household generator is not as great as that of a car, which is expected to run hundreds of thousands of kilometers without overhaul. Here it is measured in engine hours and for ordinary household gasoline models it is declared between 1000 and 2000 hours. In other words, it is 4-8 months of work for 8 hours a day. But in fact, cheap Chinese products sometimes do not work for 200 hours — and that is not enough. If something happens, generator repairmen exist, just like there are for car engines.
Ecoflow Dual Fuel inverter smart generator with the possibility of consuming gas instead of gasoline recharges the largest Ecoflow Delta Pro charging station.
And in order to consume much less engine resource and fuel, the generator is combined with a battery system. In the most primitive version, it is simply charging some Ecoflow from a generator (there is even an inverter generator from Ecoflow with smart functionality that fits perfectly with their Delta series stations). And the most complete scheme is the battery system described above with a hybrid inverter, to which a generator is added as a substitute for the network. Thus, when the network disappears, the system switches to operation from batteries, and only when they are noticeably discharged, the generator is turned on to recharge them. What this gives is easily illustrated by an example:
We have a system with a 48 V 200 A (9600 Wh) LiFePO4 assembly and an inverter that charges them with a current of 50 A (2400 W). With a consumption of 300 Wh, the charge will last for 32 hours. If you turn on the generator at this moment, it will have to work for 4 hours, producing a power of 2700 Wh (300 W consumption + 2400 W charging), after which the system will be ready to work for the next 32 hours on batteries. Approximately 6-8 liters of gasoline will be used for each such charging cycle. As a result, a month of full round-the-clock autonomy will cost 120-160 liters of gasoline (6,000-8,000 UAH in December 2022 prices) and 80 hours of generator resource (one oil change after 50 hours).
If you try to calculate a similar autonomy for a house without a battery system at all, then you will get a titanic 30*24=720 engine hours, during which 500 liters of fuel will be burned, in the most economical case (25,000 UAH). It will be necessary to change the oil 14 times, so the consumption of 10 liters will add about 3000 hryvnias… For a more realistic calculation, of course, in the second case, you need to include the correction for turning off every 4 hours for rest, which will reduce all figures by about 25%, but at the same time, the household will be without power at all… And it is absolutely unknown how many “motor days” an average generator will live in this mode without overhaul. In the first case, we have the full-time operation of all system components, in the second case, we have an attempt at some kind of marathon survival record of the generator.
Goso F20 is a hand charger. The practical benefit is questionable, but the price tag for them in Ukraine has soared to UAH 2,500-4,000!
As exotic among the generators, we cannot fail to mention two more options:
- A dynamo-machine on muscle traction. You can insert a joke about captured Russians on exercise bikes, but the manual version can really produce something like 20 watts. It is enough to slowly charge a power bank, for example. It is ironic that even such products have noticeably increased in price since October 2022…
- Solid fuel generation. On a national scale, coal-fired thermal power plants work perfectly, but there are no serial consumer solutions on our market. Alas, a conventional wood-burning stove with Peltier elements installed on the sides and an inverter should work well… And it does, but it is not sold in Ukraine.
The fourth step: alternative energy
This section will be the shortest, because the author has minimal personal experience so far… So, the peak of practical energy independence in the Ukrainian conditions is the installation of solar panels. Their power and efficiency may be different, but the result is the same — energy is conditionally “from nowhere” or at least “for free”. Physicists are laughing here, because it is impossible to bypass the law of conservation of energy. But in a practical sense, the conversion of solar, water or wind energy does not cost the user anything, while gasoline, gas or diesel fuel for the generator must be purchased for money and stored until consumption.
Wind energy or its own micro-hydroelectric power station remain a curiosity for Ukraine, so there is no point in deliberately considering them here. And, probably, every person who has already reached such an extreme choice knows about energy independence better than the author… But solar panels have long been popular, including thanks to the so-called “green tariff” from the state, which allows solar generation not only to save, but also to earn. Therefore, there is no shortage of information or offers on the market. For the purposes of this material, it is important to note just a few points for those who are starting to understand the topic.
Ecoflow Delta solar charging in tourist conditions.
Obviously, solar panels only produce energy during the day. It is less obvious that a long sunny day in July in Kherson and a short gloomy one in December in Kyiv differ by several dozen (!) times in terms of generation efficiency. In general, the declared capacity of the panels, in contrast to the characteristics of the generator, is a theoretical maximum, which is unrealistic to approach in the conditions of Ukraine. There is technical progress in the industry, the efficiency of the panels is improving, but “no magic”, as always – only the methodical work of a large industry that has not yet created anything fantastic in terms of characteristics. This should be remembered when studying market offers.
In order for the system to work at all, in addition to the battery, you need at least the same hybrid inverter that will supply 220 V to the network. This is how “commercial” stations under the green tariff work, for which it is important not to give energy independence to the owner, but direct earnings with payment for kilowatts. But it is not enough that the energy can be used only in those hours when it is produced – the standard “green tariff” system itself works only when it can send energy to the existing network! That is, when the light is turned off, you can send it anywhere and, unexpectedly, use it autonomously as well. To be able to at least take energy for own consumption without the grid, you need an inverter that can work autonomously. That is why sellers of solar stations divide solutions into autonomous, hybrid and “green tariff”.
5 kW solar panels from Tesla complete with Powerwall.
In order not only to use during generation, but also to collect energy, batteries are added to the solar system. Or, if you follow the logic of this material, then on the contrary, the already existing battery system with a hybrid inverter can be expanded with solar panels as an additional source of energy in addition to the actual network and generator! This will reduce the estimated costs for the “month of energy independence”, although in different ways depending on the time of year. Perhaps, in the summer, the generator will not be needed at all. Well, as part of the discourse of “survivalism” – in the complete absence of fuel, it will be possible to collect at least some amount of energy on any day. The same is true for the smaller panels offered for charging stations.
Solar panels with a declared capacity of 5 kW occupy most of the roof of an average private house. Their real effectiveness also depends on orientation and inclination. So this solution is almost impossible for an apartment. Ideas like “hang it on the balcony window”, if they work at all (sunny side, placement not behind the glass, but in front of it) will be limited by the level of charging the power bank for a day. However, it is better than nothing.
The author wanted to do a real independent power supply for the house a long time ago for hobby purposes. The current war only intensified these plans. One way or another, various power banks, UPSs, inverters, batteries, chargers and generators have come and gone in the household, but all of them have been used more actively since October 10, 2022 than in previous 9 years … At the time of writing I’m looking for a 48v LiFePO4 build and thinking about solar panels in the spring.
Unfortunately, independent solutions are likely to be needed even more in the coming months. But our victory in the war with Russia will certainly come and return the topic of energy independence to the niche of “survivalists”, tourists and “green tariff payers”. The market will be filled with cheap second-hand generators and inverters, Ecoflow will be useful only for trips to nature, and spare batteries will be enough for all cars in Ukraine several times. And what is important: most likely, we will all come to this moment with stable habits and a clear understanding of smart energy saving. This will be useful for the environment and the economy of Ukraine for ten years to come. Well, for now – “without light, but without you“, as the President said.