Backup Power Recharge Time Planner — Calculate Battery Recovery Time
Estimate how long a backup battery system needs to recharge after an outage, then compare the normal recharge time with a faster-charger scenario.
Recharge inputs
How recharge time is calculated
The planner first calculates the energy that must be restored between the current SOC and target SOC. Charging losses are then included by dividing the stored-energy requirement by charging efficiency.
Why target SOC matters
Recharging from 25% to 90% is materially different from charging from 50% to 80%, even with the same battery and charger.
Why charger power is not stored energy
A 20 kW charger does not restore 20 kWh every minute. At constant 20 kW, it can theoretically deliver 20 kWh in one hour before charging losses and control limits.
Recovery window
Compare the modeled recharge time with the time available before the next expected outage or operating requirement.
Limitations
Temperature, battery age, charge tapering, charger limits and BMS control can make actual recharge time longer.
Frequently asked questions
Can the target SOC equal the current SOC?
Yes. The calculated recharge time is zero.
Can the target be lower than the current SOC?
No. A recharge plan should not have a target below the present state.
Does this size the charger?
No. It compares entered charger power against the required recovery window.