Technology
Battery storage
LFP batteries store the daytime sun for the evening and keep the house running during outages. Packs have fallen to $70 per kWh, but a turnkey system is still expensive.
Price from: 16,400 ₽ per kWh Russia
2.6 m ₫ per kWh Vietnam
How it works
A home battery is a pack of lithium iron phosphate (LFP) cells with a battery management system (BMS) and a hybrid inverter. By day it takes the solar surplus, in the evening it gives it back to the house, and in an outage it keeps selected circuits running: lights, boiler, fridge, pump, internet.
LFP lasts 6,000 cycles or more at 25 °C, gives 90–95% of its capacity and is less prone to overheating than NMC. Modules range from 2.5 to 5 kWh; a 10–13.5 kWh wall system weighs 100–130 kg. The efficiency of the “sun → battery → house” path is about 89%.
Sodium-ion batteries went into series production in 2026 and promise to work in frost, but there are still few home products and little independent data.
Pros
- Backup with no noise and no fuel
- Evenings and nights on your own sun
- Storage packs got 45% cheaper over 2025 — down to $70 per kWh (BNEF)
- Modular: start with 5 kWh and add more
Cons
- A turnkey home system in the USA costs about $1,130 per kWh: the cells are a small part of the price
- Charging is limited in frost — it needs a warm room
- Heat shortens its life
- Fire safety requirements for the installation site
Sizes and figures
| Chemistry | LFP (lithium iron phosphate), less often NMC; sodium-ion — first production runs |
|---|---|
| Cycle life | 6,000+ cycles at 25 °C, warranty usually 10 years |
| Depth of discharge | 90–95% |
| Efficiency | ≈89% “sun → battery → house”; 92–96% on the DC side |
| Module | 2.5–5 kWh, 38–50 kg |
| Wall system, 10–13.5 kWh | ≈1.1 × 0.6 × 0.2 m, 100–130 kg |
| Temperatures | usually −20…+50 °C; charging below 0 °C is limited |
Starting prices
Benchmarks with a source and a date. The price for your property comes in the estimate after a site survey.
| What | Price | Source |
|---|---|---|
| Pack for stationary storage (average) World | from 70 $ per kWh | BloombergNEF: lithium-ion battery pack prices fall to $108/kWh · 09.12.2025 |
| Turnkey home battery, USA World | from 1,130 $ per kWh | pv magazine: residential solar prices rise 3.2% (EnergySage) · 24.10.2026 |
| LFP battery Russia | 16,400–28,400 ₽ per kWh | ТехноЛайн (e-solarpower.ru): аккумуляторы LiFePO4 · 02.11.2026 |
| LFP battery in a hybrid system (from the difference between packages) Vietnam | 2.6–5.6 m ₫ per kWh | Newsun Solar: giá lắp điện năng lượng mặt trời · 10.2026 |
Russia and Vietnam
Russia relevant
The main argument in Russia is outages: the boiler, pump, fridge and internet keep working for hours and days. Install it in a warm room (a boiler room, a basement) with fire separation: in frost, charging is limited.
Vietnam relevant
A battery covers the evening, when the sun is gone and the air conditioners work hardest; for businesses — EVN’s 17:30–22:30 peak at 5,313 ₫. Discharge from a battery charged by the sun can also be sold as surplus (Decree 243/2026). Hanoi and Bac Ninh pay up to 6 million ₫ towards a system with a battery.
When it is worth it and when it is not
Worth it
- Grid outages: hours, days, after a typhoon or a snowfall
- An evening consumption peak and an expensive evening tariff
- The surplus sells cheaply — a battery keeps the sun for you
- A site with no grid
Not worth it
- The grid is reliable, and the tariff is low and the same all day
- There is no warm, dry place to install it
- Capacity “by eye” without a list of loads — calculate the backup first
Safety and rules
Only certified batteries (IEC 62619, UL 9540A tests) with a BMS and a separate breaker.
Not in living rooms or on escape routes, not in direct sun, with ventilation and within the datasheet temperature range. For comparison: the US NFPA 855 rules limit a single unit to 20 kWh, and all units inside a home to 40 kWh.
Sources (8)
- BloombergNEF: lithium-ion battery pack prices fall to $108/kWh · 09.12.2025
- Tesla Powerwall 3: datasheet · 2026
- ESS News: China’s 314 Ah storage cell prices climb · 22.04.2026
- IRENA: Electricity Storage and Renewables · 10.2017
- Mass.gov: ESS installations in one- and two-family dwellings (NFPA 855)
- CnEVPost: CATL sodium batteries begin deployment · 05.02.2026
- Nghị định 243/2026/NĐ-CP (bản ký số) · 26.06.2026
- LuatVietnam: Hà Nội — tối đa 6 triệu đồng cho điện mặt trời mái nhà kèm lưu trữ · 29.10.2026
Goes well with
Inverters
The heart of the system: turns the direct current of panels and batteries into alternating current, decides where to take energy from and isolates the house from the grid during an outage.
Solar panels
Modules on a roof, a façade or the ground turn light into electricity. The cheapest new electricity in the world — but only by day and with big seasonal swings.
Generators and backup
A generator keeps a house running for as long as there is fuel. Best of all paired with a battery: the generator runs less often and under load.
Request for supply and installation
Describe the property — we’ll calculate it and reply, usually within two working days.