# Battery Power Budget Planner

> Estimate average current and battery runtime from duty cycles. List active and sleep currents with duty cycles to estimate average draw and battery runtime.

Part of usefulweb.site (https://usefulweb.site/). Results are deterministic calculations from the inputs and the listed assumptions; the API returns exactly what the web page shows.

## Use it
- Human interface: https://ohmforgepowerbudget.usefulweb.site/ (interactive tool at https://ohmforgepowerbudget.usefulweb.site/tool)
- JSON API: POST https://ohmforgepowerbudget.usefulweb.site/api/v1/calculate with a JSON object of inputs (schema: https://ohmforgepowerbudget.usefulweb.site/api/v1/tool)
- OpenAPI: https://ohmforgepowerbudget.usefulweb.site/openapi.json
- MCP (Streamable HTTP): https://ohmforgepowerbudget.usefulweb.site/mcp - tool `ohmforge_power_budget`

## Inputs
- loads (textarea): Loads: name, active current (mA), sleep current (mA), duty (%) - One load per row. Currents must be drawn from the battery itself.
- capacity (number): Battery capacity (mAh)
- usablePercent (number): Usable capacity (%)

## Method
- Average each load as active current times duty fraction plus sleep current times remaining fraction. Sum the averages.
- Divide usable battery capacity by total average battery current; zero current has no finite runtime estimate.

## Limits
- A planning estimate only. Capacity depends on discharge rate, temperature, aging and cutoff voltage. Account for converter losses and all loads in battery-side currents.