First thing to do on your electrical set-up is sizing your batteries according your needs. Everything depends on your own wish list: budget, luxury, amount of days self sustainable, choice of cooking with gas/induction, ...
Here's a list of our components, and their power consumption per day.
Time per day
Webasto Diesel Heater
Elgena Water Heater
Time per day
500W / 12V / 0.85 = 49A
1000W / 12V / 0.85 = 98A
45W 12V / 0.85 = 4.4A
This is a list of averages, because the power consumption varies completely on your own travel preferences. Going away in summer time will draw more power out of your fridge and fan, but will also generate more solar power. Travelling in winter will draw more out of your diesel heater, water heater, and depending on the period of travel will mean less solar power is generated.
* We left out our Elgena water heater in our total consumption calculation, as we often 'showered' in the sea, rivers or with unheated water. The days we showered with heated water we didn't cook a warm meal to minimise our power consumption, and prolong our self sustainable days.
Due to daily vibrations in a van only use multi stranded wires, unlike single stranded copper wires in a residential electrical system. Also use preflex tubes to run your wires, to help protect the wires so they won't get cut from any sharp edges or rubbing from vibrations. It makes it a lot easier as well if you have to replace a wire. We also put some extra empty preflex tubes for possible add-ons on our system.
When using an online wire size calculator, determine first the total length of the wire you need going to each device. Total length of the wire is the positive (red) wire running to the device + the negative (black) wire running back to the battery. Input the amount of amps and the calculator will determine the correct wire size.
Here is a good online calculator for your wire sizing.
The required fuse is normally listed by the manufacturer.
If there are no guidelines from the manufacturer you can use this formula: device amperage * 1,25 = approximate fuse size (round to the nearest fuse size)
A clean way of fusing all your 12v aplliances is via a fuse box. It makes your electrical set-up look a lot nicer and it makes it easy to troubleshoot if a fuse should blow. Add an extra circuit breaker on the positive wire coming from your battery to your fuse box, to have the ability to shut off power to your fuse box. Super convenient if you have to work on your 12v appliances or fusebox.
Another convenient device in your electrical set-up is a 12v switch panel. We used this in our set-up to be able to switch off our usb chargers, Webasto heater, water pump (super handy if your water reservoir is running low, and you want to protect your water pump from running dry, and risking the chance of breaking down). We didn't connect our lights through the switch panel, as we used Acegoo dimmers, which act as our switches. When not using dimmers this is certainly an option.
Here is how we did our light circuit with the Acegoo dimmers. We used Wago clams to connect the different wires.
Ective 12V LC 150L Life Po4 Litium Battery
Ective SI 20 Inverter 2000w
Victron Energy Blue smart charger IP22 12v/30
2x Eco Worthy Solar panels 180w
Victron Smart Solar MPTT 75/15
12v Fuse box
12v Switch panel
We are happy to provide this guideline to help you with your build. Use it wisely, we are not responsible for any problems that might occur. With any doubt or uncertainty contact a professional.