Van Build Guide • From the Pros
Learn From Others So You Don't Repeat Them
We fix a lot of DIY van conversions. People come to us after living in their build for a while, realizing something isn't working, or sometimes after something failed catastrophically. We're not here to say DIY is bad — plenty of people do it well. But there are patterns in what goes wrong. Here's what we see most often.
This one causes fires. Using 14 AWG wire for a circuit that draws 30 amps will heat up that wire until something melts. We've seen burnt insulation, damaged connections, and worse. Wire sizing isn't about cost savings — there are calculators online. Use them.
Fix: Calculate your actual amperage draw. Size wire for at least 125% of expected load. Use the charts.
Twist-on wire nuts. Electrical tape "splices." Connections that work fine in a house but vibrate loose in a moving vehicle. Vans vibrate constantly — every connection needs to be mechanically secure. Crimp connectors with heat shrink. Bus bars. Terminal blocks.
Fix: Use proper automotive connectors. Crimp, don't twist. Heat shrink everything. No electrical tape.
Every circuit needs a fuse sized for the wire, not the load. The fuse protects the wire. We've seen builds with no fuses at all ("it's only 12 volts!") and builds with 30A fuses on circuits wired with 18 AWG. Both are dangerous.
Fix: Fuse at the power source, size for the wire. If the wire is 14 AWG, use a 15A fuse max — regardless of load.
"100Ah should be enough" — we hear this constantly. Then Starlink draws 50-75W continuously, the fridge uses 40W, you charge a laptop, and suddenly you're dead by 2 AM. Lead-acid batteries can only use 50% of capacity. Even lithium shouldn't be drained to 0%.
Fix: Calculate your actual daily draw. Add 50% buffer minimum. For extended off-grid, 400Ah lithium is a realistic starting point.
House insulation in a van is a problem. Fiberglass absorbs moisture and loses its effectiveness. Regular foam board can trap moisture against metal. Pink panther insulation should stay in attics, not vans.
Better options: Thinsulate (made for vehicles), wool insulation, closed-cell spray foam, XPS foam board with proper vapor barrier.
You breathe, cook, and exist — all of which creates moisture. That moisture needs somewhere to go. Trap it against cold metal and you get condensation, mold, and eventually rust from the inside out. We've seen beautifully finished vans rotting behind the walls.
Fix: Either use vapor-permeable insulation throughout, or install a proper vapor barrier on the warm side. Have a ventilation strategy.
A ceiling fan isn't optional — it's essential. Two people sleeping in a sealed van generate a surprising amount of moisture. Even in winter, you need air exchange. Cracking a window isn't enough; you need active airflow.
Fix: Install a MaxxAir or similar roof fan. Run it on low overnight, always. Consider multiple vents for airflow.
You designed your layout from Instagram photos and YouTube tours, then built it. Except you've never actually lived in a van. Now you discover that thing you thought was clever is actually impractical for how YOU live.
Fix: Before building anything permanent, live in the empty van for a weekend. Use cardboard mockups. Understand your actual patterns.
Full-size beds are 54" wide. That's tight for two adults. And if you're over 6', those "creative" shortened bed platforms mean your feet hang off or you sleep at an angle. Sleep is important — don't compromise it.
Fix: Queen width (60") minimum for couples. Full length (80") for anyone over 5'10". If you can't fit it, get a longer van.
That tiny counter looked fine in the plans. Then you tried to actually cook a meal. Cutting board + hot pan + ingredients + utensils = nowhere near enough space. Cooking becomes frustrating instead of enjoyable.
Fix: Extend counters with fold-outs or cutting board covers over the sink. Plan for how you actually cook.
Where do you put your shoes when they're wet? Where does the garbage go? Where do you sit to put on pants? The glamorous stuff gets planned; the daily reality often doesn't.
Fix: Walk through an entire day mentally. Wake up, get dressed, make coffee, use bathroom, cook, eat, work, relax, sleep. Plan for all of it.
This is the mistake almost everyone makes. A Sprinter 144" starts with maybe 2,000-3,000 lbs of payload capacity (depending on configuration). A typical build adds:
That's 1,300-2,600 lbs before you even add yourself. Exceed your GVWR and you're illegal, unsafe, voiding warranties, and destroying your suspension and brakes.
Fix:
Know your GVWR before starting. Weigh things as you build. Choose lightweight materials where possible. Upgrade suspension to handle the load safely (doesn't increase legal payload, but handles it better).
If you've already made some of these mistakes, we can help. We regularly take over partial DIY builds, fix electrical systems, and redo work that isn't holding up. No judgment — just solutions.
Working on a DIY build and running into problems? Or want professional help on part of the project? Let's talk — we work with DIYers all the time.
ADDRESS:
6159 E Huntsville Rd, Fayetteville, AR 72701
PHONE:
(479) 326-9200
EMAIL:
info@ozkvans.com