12V Install Tools & Testers

Camping Trip Power Budget Calculator

Check whether your battery and charging could keep up with your daily power use for the whole trip.

This brings your figures together for a whole trip: how much energy you'll use, how much your charging might put back, and whether the battery could carry the difference until you get home. Every number on this page is your own estimate or a figure from your gear's label or manual. The page doesn't hold any appliance or charger data, and it can't tell you a system will be enough. Everything is worked out in your browser. Nothing is saved or sent anywhere.

1. Your daily use and trip

List your appliances (watts, hours per day, quantity, and AC or DC) in the Daily Energy Use & Battery Size Calculator, then use its Plan a trip link, or type its Daily energy use (from battery) figure here. That figure already includes estimated inverter losses.

Your estimate. Required, 1 to 100,000 Wh/day.
Whole days, 1 to 365.
Used to convert Wh to Ah.

2. Your battery

From the battery label or manual. For a bank, use the Series & Parallel Calculator total.
How much of the rating you plan to use, 10 to 100%. The battery calculator starts at 80% for LiFePO4 and 50% for lead-acid. Check your battery maker's recommended depth of discharge.

3. Your daily charging (optional)

Enter the average energy you expect each source to put into the battery per day. These are your estimates. Leave a source blank if you won't use it.

Estimate it with the Solar & Charging Check.
An average across the trip, including days you don't drive. See the DC-DC Charger Size Calculator.
Roughly charger amps × hours × system voltage. See the Battery Charging Time Calculator.

4. Results

How it was worked out

    What this does and doesn't tell you

    • This is a whole-trip energy balance estimate. It isn't a guarantee that your gear will run for the trip, and it isn't a system design, wiring specification or safety assessment.
    • It assumes the battery starts fully charged and that every day is the same: the same use and the same charging. Real trips vary. Cloudy days, shade, rest days without driving, hot weather for the fridge and extra visitors can all change the result.
    • It works day by day, not hour by hour. Solar arrives during the day, but much of your use may be at night, so the battery still has to carry you overnight even when daily charging matches daily use.
    • Charging can't put more into the battery than it has room for. Charger and battery limits, charge acceptance as the battery fills, temperature and cable losses can all reduce what goes back in.
    • It uses the battery's rated amp-hours × nominal system voltage for energy. Actual battery voltage varies with chemistry and state of charge.
    • Any work on 240V AC wiring, including inverter outputs, mains inlets and generator connections, must be done by a licensed electrician. Never back-feed a generator or inverter into a building's wiring.

    Next steps

    Size a battery that covers the gap with the Daily Energy Use & Battery Size Calculator and lay it out with the Battery Bank Series & Parallel Calculator. To see how long one load would run, use the Battery Runtime Calculator. Every tool is in the Calculator Library.

    ↑