Battery Backup Power Systems for Homes: A Complete Guide
Blackouts have become a part of Ukrainian daily life. When electricity disappears, the refrigerator, heating, internet, and security system stop working. A backup power system based on batteries and an inverter solves this problem: automatic switching in 10–20 ms, silent operation (unlike a generator), charging from the grid or solar panels.
LiFePO4 vs AGM: Which Battery to Choose
| Parameter | AGM (Lead-Acid) | LiFePO4 (Lithium Iron Phosphate) |
|---|---|---|
| Charge/Discharge Cycles | 300–500 | 6,000+ (at 80% DoD) |
| Depth of Discharge (DoD) | 50% (deeper discharge kills the battery) | 90–95% |
| Usable Capacity | 50% of nominal (due to 50% DoD) | 90% of nominal |
| Service Life | 3–5 years | 10–15 years |
| Weight (for 5 kWh) | ~120–150 kg | ~45–55 kg |
| Safety | Emits gases during charging | Safe, no gases |
| Price (per 1 kWh of usable capacity) | ~$100–150 | ~$200–300 |
| Price per Cycle (cost of ownership) | $0.20–0.50 per cycle | $0.03–0.05 per cycle |
| Recommendation | Temporary solution | Primary choice |
Conclusion: LiFePO4 is more expensive to purchase, but 5–10 times cheaper in terms of cost of ownership thanks to 6,000+ cycles and 90% DoD. AGM is only advisable as a temporary solution with a minimal budget.
Types of Backup Power Systems
1. Online UPS — for Critical Equipment
An online UPS provides uninterrupted power without switching (0 ms). It is used for servers, network equipment, and medical technology. Brands: APC (Schneider Electric), Eaton, CyberPower, Legrand. For home use, it is excessively expensive.
2. Inverter-Charger + Batteries — Primary Solution for Homes
This is the main option: a hybrid inverter or an inverter-charger with LiFePO4 batteries. Switching to batteries takes 10–20 ms (unnoticeable for household appliances). It can be charged from the grid and/or solar panels.
3. Portable Power Stations — for Mobile Use
Compact devices with a built-in battery and inverter. For charging gadgets, lighting, laptops. Brands: EcoFlow (Delta, River), Bluetti (AC200, EB70), Jackery, Anker. Not suitable for powering an entire house, but ideal as an additional/mobile solution.
Calculating Required Capacity
Formula: Capacity (Wh) = Power (W) × Time (h) / 0.85 (Inverter Efficiency)
| Consumer | Power |
|---|---|
| LED Lighting (5–10 lamps) | 50–150 W |
| Refrigerator | 100–200 W (average) |
| Wi-Fi Router + Modem | 20–30 W |
| Laptop | 50–80 W |
| Smartphone Charging (×3) | 30–60 W |
| Heating Boiler (electronics) | 50–100 W |
| TV | 50–120 W |
| TOTAL (basic comfort) | 350–700 W |
Example: 500 W × 8 h / 0.85 = 4,700 Wh ≈ 5 kWh — one Pylontech US5000 battery.
For 12–16 hours of autonomy or adding a water heater/air conditioner — 10–20 kWh (2–4 batteries).
Equipment Brands
Inverter-Chargers
- Victron MultiPlus-II — benchmark for reliability, modular, parallel connection, VRM monitoring. From $1,200.
- Deye SUN-5K-SG03LP1 — 5 kW hybrid, Wi-Fi, compatible with Pylontech/BYD. From $600.
- Growatt SPH — budget hybrid. From $400.
- SolaX X1-Hybrid — mid-range with EPS. From $800.
LiFePO4 Batteries
- Pylontech US5000 — 4.8 kWh, 48V, up to 16 in parallel (77 kWh). Most popular battery. From $900.
- Pylontech US3000C — 3.5 kWh, more compact. From $700.
- BYD HVS/HVM — modular HV batteries (100–400V) for Fronius, SMA, GoodWe. From $2,000.
- Dyness Tower T7 — 7 kWh, budget alternative to Pylontech. From $1,200.
- Victron Lithium Smart — 200 Ah, built-in BMS and Bluetooth. From $1,500.
Portable Power Stations
- EcoFlow Delta 2 Max — 2 kWh, expandable to 6 kWh, 2,400 W output. From $1,500.
- Bluetti AC200MAX — 2 kWh, expandable to 8 kWh, 2,200 W output. From $1,400.
- EcoFlow Delta Pro — 3.6 kWh, 3,600 W output, most powerful portable station. From $2,500.
Important Installation Nuances
- Ventilation: LiFePO4 does not require special ventilation (unlike AGM). However, the inverter generates heat — ensure air circulation around it.
- Grounding: The inverter casing and battery rack must be grounded.
- Protection: DC circuit breaker between the battery and inverter, AC circuit breaker + RCD at the output.
- Temperature: LiFePO4 operates at -10...+50°C, but the optimum is +15...+25°C. Do not install in an unheated garage.
- Monitoring: Victron VRM, Deye Cloud, Pylontech BMS — allow monitoring battery status and consumption via the app.
Cost of Backup Power Systems
| Level | Composition | Autonomy (basic comfort 500 W) | Cost |
|---|---|---|---|
| Basic | Inverter 3 kW + 1× Pylontech US5000 (4.8 kWh) | ~8 h | from $2,000–3,000 |
| Standard | Inverter 5 kW + 2× batteries (10 kWh) | ~16 h | from $4,000–6,000 |
| Full | Hybrid 10 kW + 4× batteries (20 kWh) + panels | 24+ h / autonomous | from $8,000–15,000 |
FAQ
LiFePO4 or AGM?
LiFePO4 — 5–10 times cheaper per cycle, 10–15 years of service, 90% DoD. AGM — only as a temporary budget solution.
How many kWh are needed?
Basic comfort (500 W × 8 h) ≈ 5 kWh. With a boiler and air conditioner — 10–20 kWh.
Cost?
Basic system (8 h) — from $2,000. Full system with panels — from $8,000.
Conclusion
A backup power system based on LiFePO4 batteries is a quiet, safe, and durable alternative to a generator. Pylontech + Victron or Deye is a proven combination for homes. Portable EcoFlow and Bluetti stations are an excellent mobile addition. The investment pays off with the first blackout lasting more than a few hours.
SDS designs and installs backup power systems in Kyiv. From calculation to turnkey installation with a warranty. Contact us for a free consultation.