A motorhome daily power budget is a simple list of what you run off the leisure battery (or inverter) in a typical day — lights, fridge, pump, phone charge, TV — so you can see why the battery dies overnight.
What this is for
Today’s loads, not a guessed “typical van”. The number on the battery is not a daily allowance. For what that Ah label actually means, read leisure battery size in plain English.
How to build a budget (no invented numbers)
- List each device you actually use.
- Find its power draw on the device label, handbook, or maker page (watts for 230 V / amps for 12 V).
- Estimate hours per day you use it.
- Put those figures into the Power calculator — do not guess a “typical” fridge wattage if you can read the plate.
What drains most vans
- Compressor or absorption fridge (check which you have — they behave differently)
- Inverter loads (kettle, microwave, hairdryer) — often the biggest hit
- Lights, water pump, heating fans, USB charging
A huge inverter load can empty a battery faster than a modest roof array can refill it. Fix the budget first, then read solar panel sizing.
Sources
Device nameplate, owner handbook, or manufacturer specs. We do not invent watt or amp figures. If a fitter changed the fridge or added an inverter, check their notes as well as the original handbook.