Off-Grid Power: Batteries, Solar & Electrical Systems
The heart of every camper van is the electrical system. With the latest battery technology you can have all the comforts of home off the grid. As long as you can keep gas in the tank, you can keep electrons in the battery bank. Every van is different, so every electrical system we build is designed to meet the specific use cases of each customer.
We publish our full build wire diagrams on our site and we have parts lists for each system on our Amazon Storefront(link). As always, if you need help from a pro, send an email to info@coadventurevans.com to get the conversation started.
There are a ton of useful resources these days to make sure you never run out of juice on the road. Here are some of the parts and information we’ve found helpful in our off-grid electrical journey:
Storing energy inflow for delayed use
The battery is the base of your system. Its function is to collect energy inflow from solar, shore, and alternator power sources and acts as a reservoir of power for when you need it. The most resilient off-grid power system has multiple sources of in-flow, with a battery bank large enough to accommodate at least a few days of average use without replenishment.
Use a load calculator (link) to find out how much power you need. We always recommend you overbuild than underbuild, considering it’ll be more expensive to upgrade down the road. Some sort of battery comparison blog link.
There are a ton of battery options out there these days. Most of the batteries available on the market will deliver the power you’re after. When it comes to batteries, we aren’t loyal to any brand in particular, but 99.9% of the time, we will recommend a LiFePO4 battery. This cell chemistry gives you the best combination of longevity, ease of use, and size (AGMs are heavy and big). Blog describing the benefits of LiFePO4 vs other batteries.
Here are the batteries we install most frequently:
Victron 24v 200Ah Battery - 24v systems are great for saving space in your battery compartment, using smaller/cheaper cable, and are more efficient when inverting up to 120v power.
Victron 12v 200Ah Battery - Victron makes the top of the line battery system components for vanlife and their 12v systems are tried and true van life tools.
Epoch 12v 460Ah - This battery is great. 11 year warranty. self heated. Super cheap.
Renogy option - We have moved away from Renogy batteries in most applications, but some of our builds over the last couple years have utilized Renogy.
Turning Stored Power into Usable Household Energy
Your house battery stores power in a direct current (DC) system (12v systems are most common but more and more 24v and 48v systems are being developed and installed, which voltage is right for you?)— DC power is perfect for efficient storage and low-draw devices like lights, fans, and water pumps. But larger appliances? They speak a different language.
That’s where an inverter comes in. An inverter converts your 12v, 24v, or 48v DC power into 120V alternating current (AC)—the same type of power found in home outlets. This lets you run high-draw appliances like:
Induction stoves
Blenders, coffee makers, air fryers, toaster ovens - anything you use in the kitchen
AC units (DC options are available as well, but many air conditioners run at 120V)
Electric blankets
Laptops and chargers
Here are some of the inverter/chargers we have used in the past and some places you can buy them:
Victron 2000W and Victron 3000W
Renogy 2000W and 3000W - Renogy website
Why store power at 12V?
12V is efficient for charging and storing. It’s lower voltage, meaning lower risk and less energy loss over short distances—ideal for mobile systems. Your vehicle’s alternator/battery system likely operate at 12v and most DC appliances used in modern vans utilize 12v, so this is still the most common voltage for auxiliary battery systems.
DC vs. AC appliances:
12V appliances (lights, fans, fridges, water pumps, modern van heaters, some air conditioners) draw power directly from your battery—no conversion needed. This saves energy.
120V appliances need more power, and quickly. They require that extra "velocity" of current—a faster wave pattern—to operate safely and effectively.
Think of 12V like a slow, steady stream. 120V is a high-pressure spout—necessary when you want to cook, cool, or blend.
Roof-Mounted Solar: Your Silent, Sun-Powered Charging System
Solar panels turn sunlight into free, renewable power for your house battery system. Once installed, they work quietly in the background—no engine needed.
Here are our favorites:
How much fits on a van roof?
Most setups fall between 200W–400W, though high-efficiency panels can push that to 500–600W if your roof is large enough and layout is optimized.
Why it’s great:
Solar is passive and long-lasting. As long as there’s sun, you’re charging—no noise, no fuel, no moving parts.
What to expect based on your travel style:
Run-and-Gun Vanlifers (Always on the Move):
Expect moderate returns. Driving days often mean parking in shade or not staying long enough to max out solar input. Solar is a top-off tool, not your main charge source. Charging from your alternator will get you charged up quicker.Stay-and-Play Vanlifers (Boondocking for Days):
Solar shines here. Parked in full sun, panels can deliver 100–200Ah/day, enough to power fridges, fans, lights, and laptops with no problem. Combine it with energy-conscious habits and you can stay out for weeks.
Alternator Charging: A Powerful Backup for Your Van Power System
When your van’s engine runs, the alternator generates electricity to charge the vehicle’s starter battery. With the right setup, you can tap into this energy to recharge your house battery system while driving. Almost every van that leaves our shop has some sort of alternator charging installed
Why it matters:
Alternator charging is the second-fastest way to recharge your batteries—only shore power (plugging into the grid) is faster. It’s automatic, reliable, and doesn’t rely on sunlight.
Why not just use the cigarette lighter? Cigarette lighter ports are limited to ~10 amps and lose energy unnecessarily to heat. They’re designed for small electronics, not deep battery charging.
Why you need a DC-DC charger: A DC-DC charger safely converts power from your alternator into the correct voltage and current for your house battery. It also protects your vehicle’s starter battery and ensures smart, staged charging.
Better still? A dedicated alternator. If you’re running large battery banks and have high power needs, adding a secondary alternator gives you fast, engine-driven charging without overloading your stock alternator.
Here are some of the chargers we keep coming back to:
Victron Orion - highest output Victron option. They also offer 18A and 30A chargers
Renogy 50A w/ MPPT - budget option for people installing solar and alternator charging. 2-in-1 unit. Renogy also makes 40A and 60A chargers that are dedicated alternator chargers.
Nations Starter Dual Alternator Kits - high output dedicated alternators for recharging as quickly as possible. 200A-280A (at 12v) charging kits depending on the vehicle.
The best way to conceptualize the charging is by doing some basic math. Let’s say you have a 400Ah battery bank installed in your vehicle. If you have a 50A DC-DC charger installed, it will theoretically take 8 hours to charge from 0%-100%. If you have a 200A dedicated second alternator, it would take 2 hours to fully charge the same battery bank.
explorist.life - this site is solely focused on van electrical systems. Get install help, system monitoring, parts recommendations, and more.
Engineers Who Vanlife - this site has a DIY electrical guide for beginners that can answer a lot of the questions you’re bound to run into.
If you want to go deep into the electrical system, Far Out Ride has a comprehensive guide to their van’s electrical systems.
Adventure Wagon put together a nice explainer to help you understand some of the basics of camper van electrical systems. Their product recommendations may not be right for you, but it will help you understand your needs better.
Trek Systems Energy Audit - You need to create an account to get access but this site has a bunch of useful information about Victron systems.
As always reach out to info@coadventurevans.com if you want help designing, consulting, or installing your own electrical system and check out our Wiring Diagrams and Amazon Storefront for parts lists from our previous projects and help doing your own system.
