12V build guides
The reasoning behind the numbers. How a vehicle electrical system is planned, sized, wired and protected, written for someone building it rather than someone specifying it.
<!-- gift-guides-xlink -->Where to start
If you have never built a 12V system, read overland power for beginners first, then the van electrical system guide for how the pieces connect. Those two cover the vocabulary the rest of the site assumes.
If you are sizing a system, how to size a battery bank and how to install solar on a van are the two that decide the budget. If you are wiring one, the wiring and fusing guide is the most important page on this site and the one to read twice.
Two guides cover what people discover too late. Payload and GVWR is the constraint that stops more builds than money does, and winter power covers the fact that lithium cannot accept charge below freezing without a heated battery.
All guides (16)
- 12V Wiring and Fusing Guide: Sizes That MatterThe full ABYC ampacity table, the voltage drop formula explained, the engine space derate, and fuse sizing for every 12V circuit in... Open →
- Best Gifts for Overlanders: 25 Overlanding Gift Ideas RankedThe best gifts for overlanders and van lifers: 25 overlanding gift ideas ranked by price tier from a dual-zone fridge and rooftop... Open →
- DC to DC Charging Guide: Alternator to House BatteryHow DC-DC charging works, why lithium needs it, how to size the charger against your alternator, and the cable gauge and fuses for... Open →
- How to Choose a 12V Fridge: The Decision OrderHow to choose a 12V compressor fridge in the right order: compressor class, single or dual zone, usable litres, daily amp-hours and... Open →
- How to Install Solar on a Van: Full WalkthroughInstall a van roof solar array properly: sizing the array, mounting and sealing, cable runs and voltage drop, controller selection... Open →
- How to Size a Battery Bank for a Vehicle BuildSize a 12V house battery bank properly: daily amp-hour audit, usable capacity by chemistry, days of reserve, cold weather limits... Open →
- Inverter Installation Guide for 12V Vehicle BuildsHow to install a 12V inverter safely: sizing from AC load, DC current math, cable gauge and class T fusing, placement and... Open →
- Overland Power for Beginners: Where to StartA plain-language starting point for 12V overland power: what a house battery is, how many amp-hours a fridge really uses, DC-DC... Open →
- Overland Water System Guide: Tanks, Pumps and WeightHow to build and live with a vehicle water system: tank versus cans, placement, a 12V demand pump circuit with real wire and fuse... Open →
- Overlanding Gifts Under $100: 20 Gifts a 12V Builder Will UseTwenty overlanding and van life gifts under $100, most expensive first: a Victron shunt monitor, a kinetic rope, a 100W panel, a... Open →
- Roof Rack Load Limits and Dynamic Capacity ExplainedDynamic versus static roof load, why the lower of the vehicle and rack ratings governs, what a rack and tent really weigh, and what... Open →
- Solar Panel Mounting Guide for Vans and 4x4sHow to mount solar panels on a vehicle roof: bolted brackets, structural adhesive, racks and tilt mounts compared, plus sealing... Open →
- The One Big Overland Gift: 8 Big-Ticket Gifts Matched to the TripA gift finder for the eight big overland purchases, fridge, rooftop tent, power station, compressor, lithium bank, DC-DC charger... Open →
- Van Electrical System Guide: The Whole BuildHow a 12V van electrical system fits together: house battery, DC-DC charger, solar, busbars, fusing and inverter, with wire gauges... Open →
- Vehicle Payload and GVWR Guide for Overland BuildsGVWR, GAWR, payload and towing capacity explained for overland builds, with door jamb sticker figures, CAT scale weighing axle by... Open →
- Winter Camping Power Guide: 12V Systems in the ColdHow a 12V overland power system behaves below freezing: why LiFePO4 cannot accept charge under 32F, how much capacity cold costs... Open →
Electrical safety: a 12V system is low voltage but not low energy. Every circuit must be fused at the source of power, within a few inches of the battery terminal, at or below the ampacity of the smallest conductor it protects. Size cable for voltage drop as well as ampacity, and have any lithium installation inspected by a qualified installer before it carries load. Everything on this site is researched guidance, not an electrical certification.