#capacity

Battery and accumulator maths as an API, computed locally and deterministically from basic electrical relationships. The runtime endpoint estimates how long a battery will last under a given load — from the capacity (in mAh, Ah or Wh) and the load (in watts, or amps at a voltage), with adjustable depth-of-discharge and conversion efficiency — and reports the usable energy and the runtime in hours and minutes. The capacity endpoint converts a battery capacity between milliamp-hours, amp-hours, watt-hours, kilowatt-hours and joules at a given voltage. The pack endpoint builds a series/parallel cell pack (for example 3S2P): it returns the pack voltage, capacity and energy and the total cell count — series adds voltage, parallel adds capacity. The charge endpoint estimates the charge time from the capacity and the charge current (or a C-rate), with a charge efficiency and an optional from/to state-of-charge window. Everything is computed locally and deterministically, so it is instant and private. Real-world figures depend on temperature, age, C-rate and the discharge curve, so treat the results as estimates. Ideal for consumer-electronics and IoT tools, solar and off-grid sizing, drone and RC planning, UPS and backup-power sizing, and EV and battery-pack design. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 4 endpoints. This is battery maths; for Ohm's-law voltage/current/resistance use an electronics API.

api.oanor.com/battery-api

Stadiums and sports venues around the world as an API — 7,000+ stadiums from Wikidata with their seating capacity, country and city, geographic coordinates and year opened. Search and filter by name, country, minimum capacity and opening year (the results come back largest-first, so it doubles as a "biggest stadiums in the world" ranking), or find every stadium near any coordinate by great-circle distance. Ideal for sports, travel, ticketing, maps, trivia and matchday apps. Open data from Wikidata.

api.oanor.com/stadiums-api