Cab Tools
Inverter size calculator for sleeper cab
Tick everything you run in the bunk. We total the watts, add 25% headroom, and name the inverter size — no guesswork, no popped fuses.
Inverter Size Calculator for Sleeper Cab
Your inverter size
—
Tick at least one device above to size your inverter.
Above 12V socket limits. Most accessory sockets are fused at 10–15 A (about 120–180 W). This load needs direct battery wiring with proper-gauge cable and an inline fuse.
Surge matters too. Motors, compressors and heating elements spike well above running watts on startup — pick an inverter whose surge rating is at least double your total.
That is beyond a typical single-inverter sleeper setup. Stagger big loads (never the kettle and the microwave together) or split across two inverters.
- Size for continuous watts, not peak — the big number on the box is the continuous rating; surge is separate and short.
- Pure sine wave for a CPAP machine, laptop or microwave — their manufacturers specify it.
- Add up what runs at the same time. Stagger the kettle and the microwave and you can drop a size class.
- The 25% headroom covers inverter inefficiency (typically 10–15% is lost as heat) plus small startup spikes.