List everything you use while parked
Start with cooling, the refrigerator, fans, lighting, phone charging and any inverter-powered equipment. Note whether each load runs continuously, cycles or is used briefly. Small devices can add up when they remain on through a long stop.
Use equipment labels and available monitoring information as a starting point. For medical or other essential equipment, confirm power requirements with its manufacturer and discuss reliability needs separately with the installer.
Turn the list into energy
For a steady load, watts multiplied by hours gives watt-hours. A hypothetical 40 W device running for ten hours uses 400 Wh. Cycling loads need an average over time instead of assuming the label describes every minute of operation.
Add the estimated loads, then ask the supplier how conversion losses, usable battery limits and reserve needs affect storage requirements. This worksheet is a planning tool, not a substitute for a system design.
Make two versions of the budget
Create a typical-night budget and a demanding-night budget. The second might include longer parking, stronger cooling demand or additional appliances. Label the assumptions so you can discuss which conditions the proposed system is intended to cover.
Include the expected charging window after each stop. A setup that covers one long night may still need a different plan for several similar nights separated by short drives.
Bring the worksheet to your quote
Send the load list, parked duration and charging schedule to Polar Fox with your truck details. Ask which optional equipment is required for each load and which requests fall outside the proposed package.
After installation, compare the worksheet with real charge readings over several stops. Keep notes about weather and equipment use. This turns a rough estimate into a useful operating record for future upgrades.
Explore real Polar Fox installations or contact our team for a truck-specific quote.