Inputs stay on your device
The first release has no account, database, or calculation API.
Solar and battery planning tools
Useful answers,
with the losses shown.
Size a battery bank, check runtime, plan a solar array, or map a series-parallel layout. Every estimate shows the assumptions and the upward rounding behind it.
No account Runs locally Assumptions stay editable
A calculator should show its work
Presets are starting points
Depth of discharge and efficiencies remain visible and editable.
Hardware counts round up
The tool recalculates capacity from the whole number of batteries or panels.
Seven focused calculators
Start with the question you have
You do not need to know every electrical term first. Choose the task closest to your current decision.
Solar battery calculator
Turn daily energy and backup days into nominal kWh, Ah, and an integer battery layout.
Solar battery runtime calculator
Estimate how long an existing battery bank can run an AC or DC load after real losses.
Battery backup calculator
Build an appliance list and size the energy storage needed for an outage.
Battery series and parallel calculator
Check voltage, Ah, energy, battery count, and the shape of a series-parallel layout.
Solar panel calculator
Estimate array watts and panel count from energy use, peak sun hours, and losses.
Solar panel output calculator
Estimate daily, monthly, and yearly energy from an array you already have.
RV solar calculator
Plan RV loads, battery storage, solar panels, and a controller current baseline together.
Transparent by default
Formulas, presets, and rounding live in one methodology
The methodology page records the units, default planning factors, formula version, and how installable counts are rounded. Tool results link back to the matching section.