An off-grid van is a van that does not need a campground or shore power to work. Solar on the roof, lithium in the battery bay, water tanks under the floor, diesel heat that runs on fuel instead of electricity. We build them on Transit, Sprinter, and ProMaster.
"Off-grid" is the word customers use for what we build every day. The four systems that make it real are power and electrical, climate and comfort, the water system, and the appliances that run on 12V instead of shore power. Done well, those systems talk to each other instead of fighting each other. Done badly, the van runs out of power on night two and you spend the trip hunting for an outlet.
Roof-mounted panels sized to the loads they need to cover. We install Renogy for value builds and larger arrays with MPPT controllers for full-time off-grid. The panel count matters less than how the array is wired and shaded around vents and AC.
We build banks around Epoch lithium drop-in batteries — proven cell quality, real BMS, and capacity that actually matches the spec. Bank size is sized to your loads and runtime, not a number off a forum.
Solar is one input; alternator charging and shore power are the others. Our full electrical builds use the REDARC Alpha system to coordinate all three so the bank stays full whether you are driving, parked in sun, or plugged in.
Heating off the battery is a losing battle in real cold. We install Espar diesel heaters on Sprinters and Webasto gasoline-tank heaters on Transit and ProMaster. Both run off the vehicle's fuel tank, not the house bank.
Fresh tank, grey tank, pump, plumbing, and filtration as one designed system. See Plumbing & Water. For full-time builds we add inline filtration so you can fill from sources you would not otherwise drink.
A van without airflow turns into a moisture trap. MaxxAir roof fans are in almost every build we do — they move air, fight condensation, and run on a tiny power budget all night.
The honest answer is that the number depends on your loads and how long you want to be out without driving. A weekender with a fan and a fridge needs a fraction of what a full-time work-from-van setup needs. The wrong way to size it is to copy a number off a forum. The right way is to list your loads — fridge, fan, lights, laptop, induction cooktop or gas, AC if any — and the runtime between charge events, then build the bank and array around that.
We do this with every quote. Tell Jack what the van is for and how long you want to go without plugging in, and he will come back with a system that actually covers it. Tell us about your loads →
Resistive electric heat or 120V space heaters draw enough current to drain a real bank in a few hours. Diesel and gasoline-tank heat run off the vehicle's fuel — that is why every off-grid build we do has one.
12V AC like the Dometic RTX can run off the bank, but only if the bank and solar are sized for it. If AC is critical, that is a build conversation up front, not an afterthought.
A poorly insulated van burns through both heat and cooling. We do insulation packages before any of the climate work, because it is the cheapest watt you will save all build.
We use proven parts at set prices for most builds. If yours needs something custom, we'll quote that separately so you know exactly what you're getting.
Battery banks, inverters, solar, and shore power as a single integrated system.
ExploreSee how heaters, AC, ventilation, and insulation work together as one system.
ExploreOZK builds the whole van — sourcing, design, climate, power, interior, exterior. One shop in Fayetteville, AR.
ExploreReady to design an off-grid system that actually covers your loads? Tell us what the van is for and Jack will come back with a quote. Or call (479) 326-9200.