Amp-hours alone do not tell you stored energy—voltage completes the picture. This guide walks through the Ah to Wh converter: capacity in Ah, nominal voltage, and watt-hours for apples-to-apples battery comparisons.
Benefits
- Core formula: Wh = Ah × V.
- Normalizes 12 V, 24 V, and 48 V packs to the same energy unit.
- First step before runtime, cost-per-Wh, and load-matching math.
How it works
- Enter battery capacity in amp-hours (Ah) from the label or spec sheet.
- Add nominal voltage (12 V, 24 V, 48 V, 3.7 V per cell, etc.).
- Read watt-hours (Wh)—the energy number for cross-voltage comparisons.
FAQ
How do I convert Ah to Wh?
Wh = Ah × V. Example: 100 Ah at 12 V → 100 × 12 = 1,200 Wh. The same 100 Ah at 48 V is 4,800 Wh—four times the energy despite identical amp-hour ratings.
Why convert amp-hours to watt-hours?
Loads and inverters are often rated in watts; utilities and appliances use kWh. Wh is the common energy unit for comparing LiFePO4, AGM, and lithium packs at different voltages before runtime or cost math.
Can I convert mAh to Wh?
Yes—convert mAh to Ah first (÷ 1,000), then multiply by voltage. Example: 5,000 mAh at 3.7 V → 5 Ah × 3.7 V = 18.5 Wh. Phone and e-bike cells are usually quoted in mAh; Wh reveals true energy next to a 12 V bank.
Technical specifications
- Wh = Ah × nominal_V.
- mAh → Ah: divide by 1,000.
- kWh = Wh ÷ 1,000.
- Related: ah-to-wh, wh-to-ah, battery-runtime, battery-cost.
Ah is charge; Wh is energy
Amp-hours describe how much current a battery can deliver over time at a given voltage—but the voltage sets how much work that charge represents. A 200 Ah 12 V bank and a 50 Ah 48 V bank both store 2,400 Wh. Without multiplying by volts, the higher-Ah pack looks bigger when it is not.
Compare batteries on Wh, not Ah alone
Retail listings love big amp-hour numbers at 12 V. Solar installers and EV packs often think in kilowatt-hours. Convert every candidate to Wh before runtime estimates, $/Wh cost checks, or inverter sizing. Enter each pack's Ah and V in the converter and sort by Wh—the ranking often flips what looked like a bargain on Ah.
Bridge Ah-rated banks to watt-based loads
A 1,500 W inverter load needs energy in Wh, not Ah. Once you know bank Wh, divide by load watts for rough runtime hours (before efficiency and depth-of-discharge). Pair this converter with Battery Runtime or Wh to Ah when you are working backward from a watt-hour budget to required amp-hours at your bus voltage.