Collection: Truck & Sleeper Cab

Ten hours parked, and the choice is idle the engine all night or wake up to a warm fridge. Idling costs fuel, hours on the engine and, in plenty of places, a ticket. Getting the electrical side wrong costs you a start battery in a truck stop at 5am. Here is the part most listings leave out.

No-load draw is what flattens a start battery

An inverter burns power simply by being switched on, with nothing plugged into it. The current is small and it never stops. An inverter idling at 1 amp on a 12V system pulls roughly 10 amp-hours across a ten-hour sleep, before the fridge draws a single watt. Off a dedicated house bank that is nothing. Off your starting battery it is the difference between rolling out and waiting for a jump.

Three habits fix it: switch the inverter off when you are not using it, wire it to a house battery rather than the starting bank, and read the idle figure before you buy rather than after.

Sizing a sleeper

• 12V compressor fridge: 40 to 80W running, spiking when the compressor starts.
• Heated blanket: 50 to 120W.
• 1,000W microwave: around 1,500W while cooking, more for the first second.

Fridge, blanket and lights sit comfortably on 1000W continuous. Add the microwave and you want 2000W. Both run on a 12V bank, so nothing in the cab has to be rewired to a higher system voltage.

Cable is half the install

Undersized battery cable is the most common installation fault in this category and the reason inverters run hot and shut down mid-shift. Use the gauge specified in the manual and keep the run short. Email us your run length and we will check it: support@prestonsupply.com, read by a person and answered within one business day, Monday to Friday, 9am-6pm ET. Every page states continuous power, surge power and input voltage separately, from the manufacturer sheet, so you are not sizing against a marketing number.

Stock sits in US warehouses. Orders leave in 1-2 business days and arrive in 3-7, free shipping inside the US, 30 days to return it.

Work the numbers in the sizing guide, or see the full range of pure sine wave inverters.