Battery sizing tool
Industrial battery capacity calculator
Estimate load Ah, required nominal battery capacity, stored energy, charger headroom and recharge time for industrial DC backup power systems. This tool is for charger-backed DC auxiliary supplies and mission-critical control power, not solar PV or hybrid solar battery sizing.
Preliminary sizing
Industrial battery capacity calculator
Recharge model
Current flow
During recharge, charger current feeds the load first; remaining current, capped by battery C-rate, restores the battery.
Output
Estimated result
Load Ah required
100.0 Ah
Autonomy Ah after margin
150.0 Ah
Recharge acceptance Ah
187.5 Ah
Required nominal Ah
187.5 Ah
Estimated energy
20.63 kWh
Usable capacity factor
80%
Effective voltage limit
96.3 V
Total charger output
40.0 A
Recharge current available
15.0 A
Recharge current required
18.8 A
Battery recharge limit
18.8 A
Usable recharge current
15.0 A
Estimated recharge time
10.0 h
Recharge target
Charger limited
Battery sized above autonomy Ah for the 0.10C limit, but charger headroom is still below target. Engineering verification needed.
- Charger spare current is lower than the theoretical recharge current required for the target recharge time.
- Estimated recharge time is longer than the target recharge time under the current charger headroom and C-rate assumptions.
Engineering assumptions
Required nominal Ah is the larger of autonomy Ah and recharge acceptance Ah. / Recharge check assumes 150.0 Ah must be restored within 8 h at 0.10C. / Default recharge C-rate for Lead-acid is 0.10C; user overrides require verification. / Series cells set the voltage window, not Ah capacity or recharge current; parallel strings need review. / Voltage limits are constraints only. Final Ah must come from manufacturer data and engineering verification.
Request sizing review
Send the load schedule, required autonomy, intended battery type, end-voltage requirement, site conditions and recharge-time requirement for a more detailed sizing check. For charger architecture and redundancy checks, use the industrial DC charger redundancy guide.
Request sizing review