Cost per kWh over a power station’s life

Only stations with a real street price and a sourced cycle rating appear — we never rank value off MSRP or a missing cycle number. “est.” flags a normalized or imputed input.

How the number is built

We take the 90-day median street price (never MSRP), multiply usable capacity by the 80%-equivalent cycle rating and the chemistry’s inverter efficiency to get total lifetime kWh delivered, then divide. A 70%-threshold cycle rating is derated to an 80% equivalent so every unit is judged on the same end-of-life line. The full derivation and every constant are on the methodology page — this is the same M5 metric the BatteryRank scores use, exposed as a ranked table.

Value questions, straight answers

What is cost per kWh over a power station's life?

It's the fairest single value number for a battery: the street price divided by every kilowatt-hour the unit will ever deliver through its inverter over its rated cycle life. It folds four things a sticker price hides — how much you actually paid (street, not MSRP), usable capacity (not the nameplate), rated cycles (normalized to an 80% end-of-life), and conversion efficiency. A cheap unit with few cycles can cost more per kWh than a pricier one built to last.

Why isn't the cheapest station the best value?

Because price alone ignores how much energy you get for it and how long it lasts. LFP cells rated for thousands of cycles spread their cost over far more delivered kilowatt-hours than a cheaper pack rated for a few hundred, so the 'expensive' unit often wins on cost per kWh. This table ranks by that lifetime figure, not by price — the honest way to compare value.

Why are some rows marked 'est.'?

An estimate flag means one input was inferred rather than sourced directly: a cycle rating quoted to 70% capacity is derated to an 80% equivalent for a fair comparison, efficiency was taken from the chemistry default, or usable capacity was imputed. The number is still useful, but it rests on one assumption we disclose rather than hide.

Does this include the cost of charging it?

No — this is the amortized hardware cost per kWh the battery delivers over its life, not the electricity to charge it. Charging from the grid adds only pennies per kWh, and from solar it's free. To compare running cost against a gas generator, use our generator vs battery cost tool.