Ah to kWh / Wh Battery Converter

Battery capacity gets quoted in three different units (Ah, Wh, kWh) by three different suppliers, often on the same project. For a business sizing a commercial BESS, an EV charging depot, or solar-plus-storage, the unit mismatch is where capex estimates start to wander. A 500 Ah string at 48 V is a very different proposition to a 500 Ah string at 400 V, and the kWh you actually own only becomes clear once the voltage is pinned down.

Storage economics are usually framed against peak avoidance, DSR revenue, or self-consumption of on-site generation. A site paying 70 p/kWh on a winter weekday peak and 12 p/kWh overnight has a clean arbitrage on every kWh of round-trip stored capacity, but only if the nameplate maths is right. A 200 kWh battery sized off a mis-converted Ah figure can mean 30% less usable energy than the model assumed, which is the difference between a 6-year payback and a 9-year payback.

Purely Energy's flex desk and Purely Insights platform sit on the contract side of the meter: tariff structure, capacity charges, DUoS bands, DSR availability windows and time-of-use signals. When a battery vendor proposes a system, we will sanity-check the energy maths against your actual half-hourly profile so the business case earns out against real consumption and real tariffs, not a brochure curve, and we will model the contract changes that turn a sized system into a returning investment.