- Battery runtime calculatorEnter your battery capacity in watt-hours, the running load, idle standby draw, usable depth-of-discharge, and inverter efficiency to estimate practical runtime for a Jackery, EcoFlow, Bluetti, APC UPS, or any custom 12 / 24 / 48 V bank.
- Home battery backup calculatorAdd up critical loads (fridge, well pump, internet, a few lights), pick how many hours per day you need them, set a target number of backup days, and the calculator returns the battery bank size and how much solar recharge offsets the draw each day.
- Generator sizing calculatorList your running watts and the largest motor (well pump, AC compressor, fridge), apply LRA-based starting surge, and add a safety factor for fuel headroom and altitude derating.
Calculator directory
Battery & Generator Backup Calculators
Design whole-home or partial-load backup systems with calculators that apply Battery Council International depth-of-discharge guidance, manufacturer inverter surge tables, and Tier 4 generator efficiency curves. Right-size your battery bank for critical-load runtime, compare lithium versus lead-acid lifetime cost, and pick a generator wattage class that handles motor starts without oversizing fuel burn.
Formula notes
Formulas used in this calculator group
Compare the core equations behind each calculator in this hub before opening a detailed tool.
Battery runtime calculator
- Wh_u = Wh_b × DoD × η
- t = Wh_u / W
Home battery backup calculator
- D = kWh_u / max(0, kWh_L − kWh_S)
- kWh_u = kWh_b × DoD × η
Generator sizing calculator
- W_0 = max(W_s) + W_r
- P_g = W_0 / 1000 × F
FAQ
Common questions for this calculator group
Review the most common planning questions from the calculators in this hub, with links back to each detailed page.
Which calculator in this group should I open first?
Start with the calculator whose title matches the decision you are making. The hub formulas help you compare what each tool actually models before you open the detailed page.
Why are the formulas shown as compact equations?
The hub view is a quick map. Each detailed calculator still explains the assumptions, inputs, examples, and caveats behind the equation.
Can I use these results before requesting a quote or buying equipment?
Yes, use them for early planning and comparison. Before purchase or installation, confirm the assumptions with equipment manuals, installers, utility rules, and local codes.