Why a battery does not lower the bill
A grid-connected home system in Armenia works under net metering. By day the panels power the house and send the surplus to the ENA grid; at night the house takes that energy back. The grid works as a free battery with no capacity limit.
A real battery cannot beat that. It costs money, loses about 8% of the energy on every charge and discharge, and wears out with the cycles. Moving solar power to the evening does not pay either: the night rate is only 10 ֏ per kWh cheaper than the day rate, and your daytime surplus already covers the night. So with a grid connection a battery buys backup, not savings.
When a battery makes sense
- Frequent outages. In villages, at the end of long lines or in storms, a battery keeps the house running until the grid is back.
- Heating that must not stop. A gas boiler needs electricity for its pump and controls; in a winter outage the heating stops without it.
- Work and health. Remote work, home servers, medical devices.
- Water. A well pump or booster pump that has to keep running.
- No grid at all. A summer house or a farm without a connection needs an off-grid system, where the battery is essential. That is a different design and a different budget.
Keep in mind that an ordinary grid-tied inverter switches off during an outage, even in full sun: that protects the people repairing the line. To keep power during a blackout you need a hybrid inverter and a battery, which take over the essential circuits automatically.
How big a battery you need
Start from what must keep running and for how long, not from the size of the solar system. The panels are sized to your yearly consumption, the battery to your outages.
Add up the running power of the devices, multiply by the hours without power and divide by the usable share of the battery (90% depth of discharge) and its efficiency (92%). The hybrid inverter must carry the combined load with a 25% margin. These examples come from the calculator below:
| What must keep running | Load | Outage | Energy needed | Battery | Inverter |
|---|---|---|---|---|---|
| Fridge, lights, Wi-Fi | 280 W | 4 h | 1.4 kWh | 5 kWh | 3 kW |
| Same + boiler pump | 430 W | 8 h | 4.2 kWh | 5 kWh | 3 kW |
| Same + TV, computer, water pump | 1,500 W | 6 h | 10.9 kWh | 15 kWh | 3 kW |
| Same + air conditioner | 2,700 W | 4 h | 13.0 kWh | 15 kWh | 5 kW |
A popular request is a 10 kW solar system with a battery. The panels of a 10.4 kW system produce about 1,290 kWh a month on average, enough for a large house; the battery next to them is usually chosen to carry the essentials through an evening or a night without power. Running an air conditioner or an electric heater from the battery quickly calls for a much bigger and more expensive one.
Battery loan subsidy from 25 October 2026
Decree No. 1502-L, in force since 25 October 2026, subsidises financing for solar batteries: the rate on dram loans is reduced by 8 percentage points and on leasing by 10 points. unverified It is not yet confirmed whether this covers private households; we will check your case. Read more on the solar loans and subsidies page.
Size your battery in the calculator below; for the price of the solar system itself see solar system prices for 2026 or the full calculator on the home page.
