Choosing a backup power source for a home or summer house

Selection and comparison of various backup power sources with specific parameters, consumer capabilities and prices.

Unfortunately, the solution to the problem of sudden blackouts (electricity) in our country is completely transferred to the shoulders of homeowners. Yes, emergency services still exist, but the deadline for fulfilling the application for the restoration of electricity supply is practically unlimited by anyone and can range from hours to weeks. If, God forbid, the substation transformer burned out in your collective farm, then you can assume that the end of the world has come.

The only good news is that in the courtyard of the 21st century and with the general decline of the Russian economy, energy sources appear in stores that can help in this situation. If not to keep in mind alternative energy sources: a wind generator, a solar battery, a compact hydroelectric power station, which were discussed in previous articles, we still have the choice between two devices - an inverter and a generator with internal combustion engine.

What is an inverter and how will it help us?

So, an inverter or an inverter voltage converter is a device that converts a low-voltage direct voltage (12, 24 or 48 volts) into an alternating voltage of 220/380 volts. Also, the inverter contains circuits to maintain the charge, discharge and standby condition of the batteries in the presence of voltage in the mains and its absence.

Inverter (inverter-battery system) allows you to easily and quickly create a backup power supply system. In normal operation, the house or cottage receives power from the electrical network (centralized power supply), while the batteries are being charged. In the event of a power outage, a backup power source is turned on - an inverter, which receives electricity from batteries operating in the discharge mode.

How much is an inexpensive inverter?

Estimate the monetary component. Let's start with the required power. According to statistics, the minimum power that is worth considering is 5 kW. In addition, you must determine the capacity of the batteries. This parameter determines how long your inverter will be able to maintain the indicated power in case of an accident in the main network. For example, the Is1-24-6000 (6 kW) costs 42,000 rubles without batteries, the Mobilen SP4000-c (4 kW) without batteries 33,000 rubles, the PowerStar W7 5kW / 48V (5 kW) 40,000 rubles.

Fig. 1. PowerStar W7 Inverter

We estimate the cost of the batteries and the time of continuous operation under a load of 5 kW.

For example, take the "PowerStar W7". In accordance with the passport for the product, 5 series-connected 12 V, 60 Ah batteries are connected to it. If you take car batteries of the middle price category, then this is approximately 5x3500 = 17500 rubles. The total amount will be 50500 rubles.

Now about the time of continuous operation. With a load of 5 kW, the efficiency of the device is 0.8, i.e. it will consume 5 / 0.8 = 6.25 kW. Battery input voltage at 60 V.

The current consumption will be 6250/60 = 104 A. At this current (approximately equivalent to the starter current of the car), the batteries can last 15 - 20 minutes. After that, when the voltage drops to 10 V, the inverter protection will turn them off. Our calculations are confirmed by passport data. In them, the maximum operating time at a maximum load of 8 kW is not more than 5 minutes.

If you want to increase the operating time, then you need to use batteries of a larger capacity and, consequently, a greater cost. A reasonable question arises: do you need a device for at least 100,000 rubles. capable of supporting a 5kW network for less than an hour ?! And this is not a mistake, for example, an inverter of the American company Outback Power Systems 3 kW complete with batteries costs 240,000 rubles.The maximum operating time at 3 kW is only 2.5 hours.

On how to increase electric power using an inverter, see the video:

How much is an inexpensive generator (electric generator set)?

Electric generator set - This is a special engine for liquid (gasoline, diesel fuel) or gas fuel, which is connected to the generator in a single unit. When burning fuel, the generator rotor rotates and an electric current appears in its windings, which is supplied to the consumer. The alternator may be synchronous or asynchronous. They can be single-phase and three-phase.

First of all, it is necessary to decide what fuel the generator set will run on? We have a choice between diesel fuel, gasoline and gas. Since gas is the cheapest product, it is natural to choose it. In addition, bottled or main gas is already present in the house.

Let's see how much a 5 kW gas generator costs? The price is from 35 to 40 thousand rubles, for example REG GG 7200, i.e. 6 times cheaper than the inverter! On one 50 liter cylinder (refueling cost 500 rubles) of liquefied gas, it can work for about 15 hours at maximum load!

For these generators, special automation units (autostart units) are produced, with the help of which the process of uninterrupted power supply is fully automated. True, it should be noted that the purchase of an autostart unit increases the cost of the backup power source by almost 30 thousand rubles, but still, the total cost of the system with a gas generator is much less than the cost of using an inverter for the same purpose.

Fig. 2. Gas generator REG GG 7200

You can put in a waste management and gas production system that will run the gas boiler, gas generator and your car. Such systems exist and are called biogas plants or biogas plants. Thus, we will save the surrounding space from all the heaps of garbage that have reached and save money!

I hope you read to the end everything that I have so carefully described. I think that it has become obvious to you that the most suitable source of backup power for your home or summer house is a generator with a gas-fired internal combustion engine.

If you have any objections or questions - write and share your personal experience!