Estimating capacity in watt-hours turns amp-hour labels into an energy budget you can compare to loads and tariffs. This battery capacity in watt-hours estimator uses Ah × V to project gross Wh for planning—not yet usable energy after depth of discharge.
Benefits
- Estimates gross Wh = Ah × nominal V per bank or module.
- Ranks mixed-voltage SKUs on one Wh/kWh scale.
- Feeds DoD, runtime, and cost-per-kWh next steps.
How it works
- Gather nameplate Ah and nominal bus voltage for each candidate pack.
- Multiply to estimate watt-hours; divide by 1,000 for kWh reads.
- Compare estimated Wh to daily load kWh and interconnection caps.
FAQ
What does a battery capacity in watt-hours estimator do?
It projects stored energy: Wh ≈ Ah × V. Example: estimating a 300 Ah 12 V AGM bank → 3,600 Wh (3.6 kWh) gross. Compare that to a 5 kWh LiFePO4 wall unit quoted in kWh—same unit after converting Wh ÷ 1,000.
Is estimated Wh the same as usable capacity?
No—gross Wh is full-charge nameplate energy. Usable Wh = gross × (DoD% ÷ 100) minus BMS reserve. Estimate gross Wh first, then apply DoD for outage or off-grid autonomy math.
How do I estimate Wh for multiple parallel strings?
Parallel strings add Ah at the same voltage: total Ah × V. Two 100 Ah 12 V in parallel → 200 Ah × 12 V = 2,400 Wh estimated. Series strings add voltage instead—resolve installed Ah and V before estimating.
Technical specifications
- Estimated Wh = total_Ah × nominal_V.
- Estimated kWh = Wh ÷ 1,000.
- Usable Wh ≈ estimated Wh × (DoD% ÷ 100) (next step).
- Related: battery-energy-calculator-wh, calculate-wh-from-ah-and-voltage.