Battery · Solar · Inverter · Power
Battery and power calculators
that show their working.
PowerCalcLab builds calculators for people sizing batteries, inverters and power systems — each one showing its formula, its assumptions and what it cannot tell you. A number without those is not much use.
- Calculators
- 27
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The tools people reach for first
Battery Runtime Calculator
Enter your battery and your load to estimate runtime. The calculator applies depth of discharge, battery health, conversion losses and — for lead-acid only — the Peukert effect, and shows each step of the energy budget.
Battery Charging Time Calculator
Charging is fast while current is constant and slower near full. This estimate separates those stages, accounts for loads using charger current, and shows a range when lead-acid absorption time is genuinely variable.
Battery Bank Size Calculator
Turn daily energy use into the nominal kWh and amp-hours your bank needs. The model accounts for days without charging, conversion loss, battery health, usable depth of discharge and whole-battery rounding.
Watts to Amps Calculator
Current depends on more than watts and volts. Pick your system type so the calculation uses the right relationship — power factor for AC, and √3 for three-phase.
Categories
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Battery calculators
Batteries are described in units that are easy to mix up: amp-hours measure charge, watt-hours measure energy, and neither tells you how long something will actually run. These tools keep those apart and show the working.
Solar calculators
A useful solar design keeps energy, weather and equipment limits separate. These tools turn daily loads into storage and array requirements, estimate charging from a local solar resource, and check both sides of an MPPT controller.
Inverter calculators
An inverter connects two different electrical worlds: AC loads and a high-current DC battery. These tools keep energy runtime, continuous and surge power, apparent power, conversion loss and battery current visible instead of collapsing them into one watt figure.
Power calculators
Power conversions look trivial until alternating current is involved. These tools ask which kind of system you have, so a three-phase or low power-factor load is not quietly treated as if it were DC.
Electronics calculators
Ideal circuit formulas are useful starting points, but connected circuits can change the answer. These tools expose loading, source impedance, current and component dissipation so the result remains tied to a real circuit model.
Why these are different
Evidence first. Then the number.
Chemistry-aware, not one-size-fits-all
A Peukert correction is applied to lead-acid, where it belongs, and deliberately not to LiFePO4, where it would mislead. Same label, very different answer.
Every step of the energy budget
Nominal energy, health, depth of discharge, conversion losses, idle draw — each one shown as its own line, with the substituted formula underneath.
Assumptions you can argue with
Defaults are typical published figures, labelled as such, and all of them are editable. Where the model stops, the page says so.
Nothing is collected
The calculators run entirely in your browser. No account, no email wall, no analytics reading what you type.