What size battery do I need for off-grid solar in Ukraine?

For a home losing power 3-5 times a week, size for two 4-hour cuts: a 5kWh (48V 100Ah LiFePO4) pack rides it with margin. Lead-acid would need 10kWh nameplate at 50% usable depth and sulfates within a year under clustered cuts. Match the inverter to the pump/blower surge, not the average load.

How many solar panels for winter in Kyiv?

December effective sun in Kyiv is ~1.1h/day. To refill a 5kWh battery you need 2.5-3kW of panels tilted ~45° south. A 1kW array sized for southern China will leave the second daily cut hitting an empty bank. Oversize for the worst month.

Will a grid-tie inverter work during blackouts?

No. By law (anti-islanding, IEC 62109) a grid-tie-only inverter shuts off the instant the line drops, so it goes dark in an outage too. You need a hybrid inverter with battery and <20ms transfer, or a true off-grid unit, to keep power when the grid fails.

Do I need a generator with off-grid solar in Ukraine?

For a real winter, yes as insurance. A 5kW array makes only ~5.5kWh in a December day vs ~8kWh load; a week of cloud drains the bank. A hybrid inverter with generator input lets a small diesel top up the pack in 2 hours. Most clients keep one.

Off-Grid Solar for Ukraine & Russia: Sizing for Blackouts and a Real Winter

Most solar sizing guides assume a grid that comes back. In Ukraine and much of Russia the grid is the thing you design around failing — shelling, load-shedding, and a winter where the sun barely shows. I size systems outside Lviv and Kyiv, and the math is different from a southern-China install. Here it is.

1. Size the battery for two cuts, not one

Cuts cluster. A family I sized for loses power 3-5 times a week, often 4 hours each. Their essentials — 150W fridge, 60W lights, 15W router, a 1.1kW borehole pump running 10 min twice a day, 40W gas boiler controller — draw ~3.2kWh/day, with a 2.4kW pump surge. One 4h cut is ~1.3kWh. I spec a 5kWh (48V 100Ah LiFePO4) pack so two cuts back-to-back still leave margin. Lead-acid at 50% usable depth needs 10kWh nameplate for the same capacity and sulfates within a year under clustered discharges. That kills lead-acid here.

2. Oversize PV for December, not July

Kyiv December effective sun is ~1.1h/day; July is ~5.5h. A 1kW array sized for a Guangdong install makes almost nothing in a Ukrainian December. To refill a 5kWh battery before the next cut you need 2.5-3kW of panels, tilted ~45° south. We sent 3kW. Undersize and the second cut of the day hits an empty bank while the first is still dark.

3. Match the inverter to the surge

The borehole pump and boiler controller surge 2-4× running watts at startup. That 2.4kW pump spike ruled out the cheap 2kW inverter a neighbour bought — it faulted on every pump start. We used a 6kW hybrid unit; its 10ms transfer keeps the fridge unaware the grid dropped. A grid-tie-only inverter cuts out completely the moment the line dies (anti-islanding, IEC 62109) — useless in a blackout.

4. Generator input + BMS comms are not optional

A week of December cloud drains the bank faster than PV refills it. The hybrid inverter must take a diesel/petrol generator input — most Chinese hybrids (Deye, Growatt, Luxpower) do. And it must speak CAN/RS485 to the LiFePO4 BMS on the Pylontech profile most 48V packs use. Without BMS comms the inverter misreads SOC and disconnects at 30% with a full pack. I have seen that failure; it looks like a dead battery.

5. C-rate beats watt rating

A 100Ah battery at 1C delivers 5kW. The 2.4kW pump surge is safe. A 50Ah pack at 1C gives only 2.5kW and the pump stalls. Check the pack's C-rate against your largest motor surge before you trust the inverter's rated watts — the battery, not the inverter, is usually the bottleneck on switch-over.

Want a pack + inverter matched to your region?

Send your surge load, your winter low, and whether you keep a generator. I will match the LiFePO4 C-rate and the hybrid inverter rating — and flag the pump surge most quotes miss.

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