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Camper Power Reality Calculator

Find out how long your battery lasts with the loads you actually run. Every number below is an editable assumption. Replace it with your label ratings or measurements for a better estimate.

01 Battery

System voltageChemistry

Rated capacity Ah, total bankUsable capacity % you plan to use

Chemistry sets a starting point: 80% for LiFePO4, 50% for lead-acid. Your battery datasheet is the authority.

02 Daily loads

Watts × hours is the energy per day. For a fridge, enter the hours the compressor actually runs, not 24.

03 Inverter applies only to loads marked 230 V

Efficiency %Idle draw WSwitched on hours/day

04 Charging

Solar panels Wp, totalPeak sun hours per day

Scenarios are illustrations, not data for your location. PVGIS from the EU Joint Research Centre estimates solar output for a specific place and month.

System losses % of rated output keptDC-DC charger A, 0 if noneDriving hours/day

Estimated autonomy

Estimate

1.2 to 1.6 days

From full charge to your usable limit. The lower figure assumes 20% more use and 30% less charging.

Usable energy: 1920 Wh of 2400 Wh rated
Daily use: 1631 Wh
Daily charging: 450 Wh
Daily balance: -1181 Wh

Where the daily energy goes

12 V loads932 Wh
230 V loads540 Wh
Inverter conversion loss95 Wh
Inverter idle draw64 Wh
Solar450 Wh
Alternator0 Wh

Not in this estimate

Load figures are starting assumptions until you replace them with label ratings or measured values.
Capacity assumes a healthy battery at its rated Ah. Age, cold and past deep discharges reduce it.
Inverter efficiency and idle draw are estimates. Both vary with the model and with how lightly it is loaded.
Fridge running time rises with outside temperature and how often it is opened.
Starlink draw changes with temperature, obstructions and usage. Snow-melt and start-up can draw more.
Solar output depends on location, season, shading, panel angle and the charge controller. Check PVGIS for your area.
Cable losses, standby loads and the BMS cut-off point are not included.

Next step · in preparation

Camper Power Planning Kit

Starlink and laptops are the loads remote workers most often underestimate. The kit records what each really draws and plans the inverter-free options.

Planning kit, not on sale yet. See what is inside and get notified.

How the estimate works

Simple arithmetic, shown in full.

Usable energyvoltage × Ah × usable %
12 V loadswatts × hours, summed
230 V loadswatts × hours ÷ inverter efficiency, plus idle draw × hours on
Solarpanel Wp × peak sun hours × system losses %
Alternatorcharger amps × driving hours × voltage
Autonomyusable energy ÷ (daily use − daily charging)

This is a planning estimate from the figures you enter. It is not a wiring design, a fuse or cable sizing tool, or a safety assessment. Mains (230 V) and gas work in a camper belongs with a competent installer.