The short version: we turned a cargo van into an off-grid rig for a motocross family. It has a 628Ah Epoch lithium battery bank, a Victron MultiPlus-II 12/3000 inverter/charger, 400 watts of rooftop solar, a 50-amp Orion XS charger that refills the batteries while driving, and a 12V air conditioner that runs straight off the battery bank, no generator required. We did the roof work and the complete electrical system; the owner is finishing the living space himself.
The Goal: A Dune Rig That Stays Cool
The owner races motocross. He wanted a van that could haul his bike in the back, sleep his wife and kids in a loft, and keep everyone cool on long weekends at the dunes without running a generator. That meant an air conditioner that runs from the batteries, enough battery to carry it, and two ways to put the power back on the road: solar and the alternator.
We built it on-site at a storage yard in Marana, just northwest of Tucson.
What We Installed
- 628Ah Epoch lithium battery bank (2× 314Ah)
- Victron MultiPlus-II 12/3000 inverter/charger
- Victron SmartSolar MPPT 100/30 charge controller
- 400 watts of rooftop solar (4× 100W panels)
- Victron Orion XS 50A DC-DC charger for charging from the alternator while driving
- Victron Cerbo GX and GX Touch display, with remote monitoring through Victron’s VRM portal
- Victron Lynx Distributor, a 400A Class-T fuse and a BEP battery disconnect
- Maxxair Deluxe roof fan
- OutEquipPro 12V air conditioner
- Four 120V outlets on two 20-amp circuits, plus pre-wired 12V lighting circuits
The Roof Work
Day one was all roof. We cut the openings for the Maxxair fan and the 12V air conditioner, and built a new mounting base for the AC rather than routing its power cable underneath, which didn’t suit this van. Every roof penetration, including the solar cable entry, is sealed with Sikaflex and smoothed to a clean finish.
The four 100W panels are wired in series, since this roof has no shading to work around, and the cables are routed to stay tidy and out of sight.
The Electrical System
Everything is built on a custom Victron board that mounts to the van’s partition wall. The 628Ah battery bank sits right beside where the owner’s bench seat will mount. From the batteries, power runs through a 400A Class-T fuse and a BEP disconnect to the Lynx Distributor, which ties the charging sources and the inverter together:
- Solar: the SmartSolar MPPT 100/30 charges from the 400W array.
- Driving: the Orion XS pulls 50 amps from the alternator whenever the van is running.
On the 120V side, the MultiPlus-II 12/3000 delivers about 2,400 watts continuous. We provisioned 30 amps and split four outlets across two 20-amp circuits, so there’s plenty of power for whatever gets plugged in.
On the 12V side, a 15-amp circuit runs the roof fan. Two more circuits are already wired, labeled and fused at 10 amps, ready for the six ceiling lights the owner is installing.
The Cerbo GX runs the GX Touch display on the partition wall and sends the system’s data to Victron’s VRM portal, so the owner can check battery, solar and charging from anywhere.
How Much Power Does a 12V Air Conditioner Use in a Van?
On this build, the 12V air conditioner drew about 52 amps at full power, and the Maxxair fan drew just 3 amps on its highest setting. With a 628Ah lithium bank, that works out to roughly 12 hours of full-power cooling from a full battery before any recharging, and in real use an AC cycles on and off rather than running flat out for hours.
While driving, the 50-amp Orion XS covers nearly all of that draw, and the 400 watts of solar add more whenever the sun is up. Because the AC runs on 12V directly, it doesn’t need the inverter at all, which is why we consider a 12V unit the best choice for an off-grid build like this.
What the Owner Finishes
We handed the van back ready for the owner to build out the living space: the bench seat, the partition walls, a loft bed for the family, the wall and ceiling panels, and the six 12V ceiling lights, whose circuits are already run and fused.
A system that pulls this kind of current needs to be built right. It was installed and commissioned by an ABYC Certified Electrician and Victron Certified technician, to the same electrical-safety standard marine and RV electrical professionals are held to.
Related Guides
- How Many Lithium Batteries Do You Need for RV Solar?
- Victron vs. Renogy for RV Solar: Which Should You Install?
- Orion XS Emergency Reverse Charge
Want a system like this in your van or RV? Get a free consultation and we’ll size it around your rig and how you travel.
