Click here to download the 400 Watt Solar System Diagram
A 400 Watt solar system is by far the most common van set up on the road today. We personally have been using our 400 Watt system with DC-DC charging for about 3 years now.
With our system we’re able to run a Maxxairfan, a small DC Refridgerator, LED lights, Cellphones, Laptops, induction cooktop, diesel heater, and a water pump for the kitchen. During sunny weather, we do all of our cooking with induction.
You can expect to pay anywhere from $700 to $1200 for this size solar system without the cost of batteries. Your exact cost will depend on where you source your equipment.
Components List
Main Components
- 40A MPPT Solar Charge Controller
- 2000W Inverter/Charger
- DC Fuse Panel – Wire your DC circuits under 30A through this Fuse Panel
- 30A DC-DC Charger
Solar Array
- 200 Watt Solar Panel
- 10 AWG Solar Cable – 20′ of Solar Cable with MC4 connectors on one end
- Solar Disconnect – Main Switch to disconnect the Solar Array
- Solar Cable Entry Gland – Entry gland with MC4 connectors and wire already attached
- Solar Panel Glue on Mounts
Battery Bank
- 200A LiFePo4 Battery – (Recommended Option)
- 200A LiFePo4 Battery – (Budget Option)
- 200A AGM Battery – (Budget Budget Option) Important– If using AGM batteries you’ll need twice the capacity since these batteries should not be discharged below 50% capacity.
- Main On/Off Switch
- Battery Monitor and Shunt
Everything else
For everything else needed to complete your project, please visit our Installation Components Page. There you’ll find all of the fuses, breakers, busbars, wires and tools you’ll need for this project.
Installation Guide
For detailed instructions on how to build and install this system, please read our Solar System Installation Guide.
Component Information
Power Inverter
A power Inverter converts DC electricity (from your batteries) into AC electricity. AC electricity is used to power typical household appliances. If you don’t plan to use household appliances, then you won’t need to install a power inverter.
This design uses a 1500 Watt Power Inverter, but feel free to use a smaller inverter or skip the inverter altogether if you don’t need to power A/C devices. If you wish to install a larger inverter, you’ll need to recalculate your cable and fuse sizes. Read our Guide to Wire Selection or Guide to Fuse Selection.
If you plan to plug in at a campground, we recommend installing this Inverter/Charger. Inverter/Chargers have a built-in battery charger and transfer switch, which allows you to plug into campground poles or normal household outlets.
DC-DC Charger
A DC-DC Charger let’s you generate power on demand, whenever you’re engine is running. So if you do alot of driving or you’re planning to do winter vanlife and you want a backup charging method, do yourself a favor and install a DC-DC Charger.
- 30 Amp DC-DC Charger For campervans and trucks
- 18 Amp DC-DC Charger For smaller engine vehicles
Solar Charge Controller
We recommend installing the Victron 100|30 MPPT Solar Charge Controller for this solar system. You can however, choose any charge controller you want as long as it’s specifications meet or exceed the Victron 100|30.
Solar Panels
This design uses two 200 Watt Solar Panels. These are “12 Volt” solar panels, which have a Voc of around 20 Volt, plus or minus a few volts. Check the back of your panels for a Voc rating, make sure it falls between 16 to 24 volt. Anything higher is not compatible with this design.
The solar panels are to be wired in series for this design. If you wish to wire them in parallel you’ll need to fuse each panel accordingly and recalculate solar cable sizes. Read more about When to Wire Solar Panels in Series or Parallel here.
Other Useful Resources

Browse our other 12-Volt Systems
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