Energy targets often arrive in watt-hours; battery shopping lists amp-hours. This guide walks through the Wh to Ah converter: your Wh budget, nominal bus voltage, and equivalent amp-hour capacity.
Benefits
- Core formula: Ah = Wh ÷ V.
- Works backward from solar yield, load budgets, or inverter autonomy targets.
- Pairs with Ah to Wh for round-trip battery sizing checks.
How it works
- Enter your energy target in watt-hours (Wh)—daily load, bank size, or pack rating.
- Add nominal system voltage (12 V, 24 V, 48 V, etc.).
- Read equivalent amp-hours (Ah) for bank or pack selection.
FAQ
How do I convert Wh to Ah?
Ah = Wh ÷ V. Example: 1,200 Wh at 12 V → 1,200 ÷ 12 = 100 Ah. The same 1,200 Wh at 48 V needs only 25 Ah—higher voltage means fewer amp-hours for the same energy.
When do I need Wh to Ah instead of Ah to Wh?
Use Wh to Ah when you start from an energy budget—daily watt-hour load from appliances, solar production in Wh, or inverter runtime math—and need to shop for Ah-rated batteries at your bus voltage.
What voltage should I use?
Use the nominal voltage your loads and inverter connect to—12 V RV, 24 V marine, 48 V off-grid, or 12.8 V LiFePO4 nominal. Marketing cell voltage (3.7 V) is for single cells, not finished 12 V packs.
Technical specifications
- Ah = Wh ÷ nominal_V.
- Wh = Ah × V (reverse check).
- kWh → Wh: multiply by 1,000 before dividing by V.
- Related: wh-to-ah, ah-to-wh, battery-bank-size, battery-runtime.