Rules
Payload: how to keep your camper comfortably under 3,500 kg
Weight is the easiest part of a van conversion to get right, on one condition: you do the sum before you build rather than after. That takes half an hour. Below are the numbers to do it with, and the four places where you save tens of kilos without giving anything up.
Updated on 12 min read
The sum in one line
Permissible maximum mass minus kerb weight is your payload. Both figures are on your registration document. Everything you then put in the van — the conversion, water, gas, batteries, people, bicycles, a suitcase — comes off that payload. Not off the kerb weight: off what is left.
The kerb weight on your registration document is a factory figure for a base model. Every option your van has and the base model does not — towbar, air conditioning, sliding doors on both sides, a bigger battery — is not in it. Allow fifty to a hundred kilos of difference, and weigh the van if you want to be sure.
What weighs what, roughly
| Item | Weight | Note |
|---|---|---|
| Insulation and wall panelling | 60 – 110 kg | Poplar plywood saves a lot over birch |
| Floor build-up | 40 – 70 kg | Battens, board and covering combined |
| Complete furniture fit-out | 120 – 260 kg | Strongly dependent on bed size and cabinet count |
| Water tank, 100 litres full | 105 kg | Water weighs a kilo per litre, plus the tank |
| 100 Ah lithium battery | 11 – 14 kg | A lead battery of the same capacity weighs twice as much |
| 200 Wp solar panel | 11 – 13 kg | Plus the roof mounting |
| 11 kg gas cylinder, filled | 24 kg | The steel cylinder alone weighs thirteen kilos |
| Two adults | 150 – 170 kg | Inspections reckon 75 kg per person |
| Luggage, tools, food, chairs | 80 – 150 kg | Systematically underestimated |
Add up the bottom half of that table: water, battery, gas, two people and luggage together quickly reach 350 to 450 kilos — before a single board of furniture. A Ducato L2H2 with a kerb weight around 2,050 kg therefore has roughly 1,000 kg left of its 3,500, half of which is gone before you start building.
The total is not the only figure
Alongside the maximum mass, your registration document also gives a maximum per axle. You can be comfortably under 3,500 kg and still be overloaded on the rear axle, and that is exactly what happens when the bed, the garage, the water tank and the batteries all sit at the back. You notice it in crosswinds, in braking distance, and in your rear tyres.
- Put the water tank as close to the middle of the van as possible, between the axles.
- Batteries belong low and between the axles, not in an overhead locker and not at the back.
- The garage under the bed is the heaviest place in your whole camper. Budget it full, not empty.
- Drive to a weighbridge once with everything loaded. Fifteen euros, and you know instead of assume.
Where you save weight without losing anything
- Poplar plywood instead of birch: same thickness, roughly a third lighter. For cabinet sides that carry nothing, that is the single biggest easy gain in the project.
- An aluminium extrusion frame instead of solid timber uprights saves tens of kilos and stays stiffer.
- A smaller water tank you refill more often. Fifty litres less is fifty kilos, every day, all year.
- Lithium instead of lead: at equal usable capacity it halves the weight and doubles the life.
Our layout engine includes the weight of every set and shows on each floor plan what is left of your payload. That figure is deliberately the furniture only — water, batteries and luggage you add yourself, and that is exactly what the calculator is for.
What you need for this
We do not (yet) sell these parts separately. The list is here because this is what should be in your basket before you start.
- 15 mm poplar plywood for cabinet sides
- 20 × 20 mm aluminium extrusion with corner connectors
- Flat water tank for under the floor or a bench
- 100 Ah lithium battery with battery monitor
Frequently asked questions
- How much payload do I need for a self-built camper?
- Reckon on 350 to 450 kilos for water, gas, batteries, two people and luggage, plus 220 to 440 kilos for insulation, floor and furniture. Below 700 kg of payload you have to make choices; below 500 kg you cannot get there without cutting water capacity or bed size.
- Is the kerb weight on my registration document accurate?
- Usually not exactly. It is a factory figure for a base model; options such as a towbar, air conditioning or a second sliding door are not included. Fifty to a hundred kilos of difference is normal. A weighbridge costs fifteen euros and settles the matter.
- Why does staying within the weight limit matter so much?
- For three reasons, and all three are good news if you calculate in advance. Your braking distance stays what the manufacturer intended. Your insurance pays without discussion, because an overloaded vehicle hands an insurer an argument you would rather not give. And at a roadside check there is simply nothing to talk about. One trip to a weighbridge costs fifteen euros and takes the subject off your list for good.