#rv

Propane and LPG tank maths as an API, computed locally and deterministically — the usable-fill, energy and burn-time numbers a homeowner, RV-er, grill-master or HVAC tech works out at the tank. The tank endpoint turns a tank size into real numbers: liquid propane is 4.24 lb per gallon and holds 91,452 BTU per gallon (about 21,569 BTU per pound), so a 20 lb barbecue cylinder carries roughly 4.7 gallons and 431,000 BTU. It knows the two ways tanks are sized — a portable cylinder (20, 30, 40 lb) is rated by the propane weight it holds, while a bulk tank (100, 250, 500, 1000 gal) is filled to only 80 % of its water capacity to leave room for expansion, so a 500-gallon tank actually holds 400 gallons of propane and about 36.6 million BTU. The burntime endpoint divides that energy by an appliance’s BTU-per-hour input rating to give run time: that same 20 lb cylinder runs a 30,000 BTU/hr patio heater about 14 hours, and an optional hours-per-day turns it into days. The refill endpoint costs a fill from a price per gallon, gives the cost per 100,000 BTU so you can compare propane to natural gas or electricity, and — with an appliance rating — the running cost per hour. Everything is computed locally and deterministically, so it is instant and private. Ideal for home-energy, HVAC, RV, off-grid, grilling and outdoor-living app developers, fuel-cost and tank-monitor tools, and propane-delivery calculators. Pure local computation — no key, no third-party service, instant. US units. Live, nothing stored. 3 compute endpoints. For vehicle fuel economy or the ideal gas law use a different API.

api.oanor.com/propane-api

Trailer-towing weight maths as an API, computed locally and deterministically. The tongue endpoint computes the tongue (hitch) weight as a percentage of the loaded trailer weight and reports the recommended 10–15 % range — too little tongue weight is the main cause of trailer sway. The capacity endpoint computes the maximum trailer weight a tow vehicle can pull, GCWR − curb weight − payload (the passengers and cargo in the vehicle), and checks a proposed trailer against it with the margin remaining. The payload endpoint computes the vehicle payload still available once the trailer is hitched, GVWR − curb weight − tongue weight, since the tongue weight presses down on the tow vehicle and counts against its payload rating. Everything is computed locally and deterministically, so it is instant and private. Ideal for RV, caravan, trailer and fleet apps, tow-vehicle matching and load-planning tools, and automotive calculators. Pure local computation — no key, no third-party service, instant. Live, nothing stored. Guidance only — follow the manufacturer's ratings. 3 endpoints. This is trailer-towing weights; for tyre size and rolling circumference use a tyre API.

api.oanor.com/towing-api