Estimated recharge cost
Rsย 99
Uses an 80% charging-efficiency assumptionHow this calculator helps
Estimate the grid energy used to recharge a battery bank after an outage. Battery voltage and amp-hours provide nominal stored energy, while the chosen recharge percentage and a fixed conversion-loss allowance produce purchased units.
How to use it
- 1
Enter the battery bank voltage and rated amp-hour capacity.
- 2
Estimate the percentage of capacity restored after the outage.
- 3
Enter an effective electricity unit rate and compare with measured charging energy when available.
Formula and methodology
Grid energy kWh = voltage ร amp-hours ร recharge percentage รท 100 รท 1,000 รท charging efficiency. This estimate uses 80% efficiency.
Worked calculation example
Recharging 80% of a 150 Ah, 12 V battery stores 1.44 kWh. At 80% charging efficiency, approximately 1.8 grid units are purchased.
What can affect the result?
Battery chemistry
Lead-acid and lithium batteries have different charge efficiency and usable capacity.
Charger behaviour
UPS electronics, float charging and tapering change energy consumption.
Battery health
Older batteries may waste more energy and store less usable charge.
Limits of this estimate
The estimate assumes 80% charging efficiency and cannot model float consumption, multi-stage charging, battery ageing or electricity slabs.
Frequently asked questions
Is the UPS charging cost calculator free?๏ผ
Yes. SolvePilot tools are free, work in your browser, and require no account.
Does SolvePilot store my values?๏ผ
No. Calculations run locally in your browser and the values you enter are not sent to a server.
Should I treat the result as an exact bill or quotation?๏ผ
No. Results are informed estimates. Final charges can vary because of taxes, tariffs, lender terms, usage patterns, or provider rules.
How can I improve the accuracy?๏ผ
Use recent values from your own bill, statement or institution, review every assumption, and confirm important results with the relevant official source.
Why does charging use more energy than the battery stores?๏ผ
Heat, charger electronics, wiring and battery chemistry create conversion losses.