Solar power for our Sprinter camper van was a top priority from day one. After a few years of free energy charging our batteries and running our fridge and laptops, I can hands-down say it was one of our best additions to the van. I highly recommend it.
There is something magical about solar power. Put a few photovoltaic panels on your roof, run some wires to your inverter and battery and POOF, electricity to run your electric shaver. And that solar power frees us up to set out across the land in a van with nothing except the fuel in our gas tank, untethered to explore with the comforts of home.
My senior project in college was designing a solar panel and battery system for an off-the-grid house. Luckily, I forgot most of that knowledge and got to experience the learning process over again! To save you some time, here is how I went about it.
Where Should I Buy My Solar Panel Kit, And How Big a System Do I Need?
Probably the most important thing to consider when setting up your solar, battery and inverter system is how big the power draw on your system will be. Are you installing a fridge? Microwave? Electric heater? It is easy to determine how to size things by looking at:
- Renogy has great solar panel kits at prices 1/3 what I paid for ours in 2013. Here’s their 200W kit with MPPT charge controller.
- The maximum voltage draw from your van’s juice-sucking components. Unless you’re planning to stick with 12V power, you’ll need an inverter big enough to handle your biggest total voltage pull. Our max is ~1500W, so we got a 2000W inverter that has worked great. If you have the space, I say go big or go home. “Oh, I’ll never use more than 350 watts. We are minimalists,” you say? Mmmm hmmm. Famous last words.
- The estimated amperage draw on your system and how long you’ll be running each appliance. This will help you figure out battery system sizing.
(Note: I’m not going to talk about wire gauge size or things like that in this post since it is so system specific.)
Sizing our system was easy. We don’t have many big loads that we run frequently except two big short-use items (Vitamix and hot water boiler at 1,500 Watts each).
LED lights, laptops, fridge, Fantastic Fan roof vent, the Espar heater fan, heating pad for bed (used briefly at night on cold nights instead of Espar), and our stereo system are the big power draws. That totals about 8-15 amps, which means we don’t drain the batteries all that fast. (With a 200 Amp-Hour system, we can theoretically run everything for 13 hours, minus the hot water boiler and Vitamix.)
I sized our system so that the solar panel system would put about 10-12 amps/hour into the system during the day in full sun at maximum power point, and then we have the electrical system rigged up to charge with excess current from the van alternator while we’re driving. This works great and we’re usually topped out with electricity unless we are not driving for awhile AND there isn’t any sunlight.
Note: we also have shore power in the form of a 15 amp cord to plug in… that we’ve used twice. I’d skip this if I did it again.
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Should I Buy Individual Pieces or an Entire Solar Panel Kit?
Costs have dropped dramatically on solar components. We paid $1500 for our 200W kit in 2013; now you can get the same system from Renogy for $500! It’s fantastic how cheap solar is these days.
Many shops also do solar installs, but the cost is painful. I say give it a shot yourself with one of the kits and save $1000+.
Below is the list of major components. All can be found on Amazon (links provided), though I’d just buy a kit to make it easy.
Example of Panels: Renogy 100W panels (two of them, easy to add more if needed)
Charge Controller: Blue Sky Solar Boost 2512IX-HV
Meter: IPN Pro Remote (this is the monitoring/control system for the solar setup)
Batteries: We’re running two Ohmmu lithium ion batteries after I updated our system in 2021.
All our stuff showed up at our door in a big box and I got right down to being overwhelmed. When you do it, breathe deeply – it isn’t that bad and I bet you’ll find it to be a satisfying project by the time you’re done.
It took me about 10 hours total to do the install. After a solid weekend of effort, you’ll be sitting pretty.
Nine Steps to Glory! (Or Wait, Where the Heck Does All This Stuff Go?)
Here are the basic steps I followed for our install. I’m sure everyone will do it slightly differently, but this worked well for me and there aren’t many things I would do differently.
Assemble your tools! I recommend a rachet/wrench set, heat gun, hole saw (~1.25”), cordless drill and bits, caulk gun and caulk, utility knife, wire cutters and crimpers, and some way to get on top of your van (ladder, tall friend, or sky hooks).
Get the panels ready for installation on the van. Attach all the mounting brackets and feet and pre-wire crimps and other attachment so you don’t have to do it on the roof of your vehicle.
Put the panels on top of the van. I recommend having someone help you, or you can do it off the top of a tippy ladder by yourself and provide entertainment for the neighborhood as you wobble about trying not to kill yourself.
Move the panels 67 times to figure out the best place to put them. Think HARD about where you’ll route wires inside the van. Make sure you consider proximity to your roof rails if you are planning to install an awning, or location relative to a Rocket Box if you are getting one of those. I suspect mounting a panel at the very front is totally fine, but I didn’t want the force from the wind off the windshield so I mounted them behind our roof vent instead, and could have put two more panels back there.
Drill the Boss-Size hole to route the panel wiring inside. I used a tap hole followed by a 1.25” metal hole saw. Nothing like tapping an inch-plus hole in the top of your new van to make measure twice, cut once sink in. Make sure you paint the edge of the hole with some kind of sealant to prevent rust.
If you have multiple panels like we did, you’ll need to somehow combine the wires from each panel before routing them through the giant hole you just drilled in your roof. I used a combiner box that came with the kit and mounted it under one of the panels. It is screwed down and sealed with lots of caulk. No leaking so far!
Once your combiner box is installed, you can mount the panels on the roof. (Or do this step last.) After a lot of research, I used 3M VHB 4950 adhesive tape. Some people screw their panels to the roof, which certainly would work, but that’s just 16 more holes to rust or leak. Make sure to put a layer of self-leveling sealant over the top of the solar panel feet/adhesive pads to prevent dirt and water from compromising the attachment and haven’t had any issues.
Updated June, 2017: A recent event made me VERY happy I used the VHB tape. A string from a deck snagged a solar panel and ripped it off the roof! Luckily, the pads peeled off, the panel wound up dangling in mid-air with merely a couple bent brackets, and it was an easy fix. If it had been screws into the roof…*gulp* Our VHB tape has lasted 35,000 miles through all kinds of weather and is holding strong, though the sealant over the feet does need a refresher.
To the inside we go! Here is where you just follow all the wiring diagrams. (See how easy that was?) Buy a kit that has all the connectors and shrink tubing clearly labeled so you don’t have to go back to your favorite hardware store (where they probably already know you by name) five more times in a weekend to get this project done. Before cutting any wire, carefully fitting and laying out the location of the charge controller, on/off switch, IPN remote and shunt relative to your inverter (if you have one) and other stuff is important or you’ll be cramming stuff into a wall cavity or struggle to find places to attach all the components. I mounted the charge controller inside the wall with flush-mounted face plates after I finalized the interior.
Turn on the beast! Hopefully there is exactly zero popping, crackling and fizzing. Crack a cold one and sit back and enjoy the fruits of your labor.
All in all, this install was surprisingly straight forward and easy. Save yourself $1,000-1,500 and do it yourself! It took me an afternoon and part of another day, plus research about the system. One weekend and you’re dialed in with power on your van!
A Few FAQs
Q: Is 200W enough?
A: Yep! The only time we’ve run lower on power is when we have practically zero sun for awhile and haven’t driven recently. You could certainly put more on there if you want. When we’re in direct sunlight, which isn’t all that hard to find where we like to go, our system is at 100% almost all the time even with the fridge running, stereo on and laptops and other stuff charging.
Q: Is your Vitamix/hot water boiler (1500W each) always able to run?
A: NO. When the voltage in the batteries gets below about 12.2V, which happens around 70% battery life, the inverter will fault. Gotta keep the system pretty topped out to run that kind of wattage and amperage pull. Note: We have started the van up and run it for a few minutes while boiling water to get around this. Works great, and only has been necessary a couple times before you think we’re earth haters. Consider getting a Ninja blender (less wattage) and/or a lower wattage hot water boiler.
Q: Aren’t you worried about your panels blowing off while you drive?
A: Initially, I was worried about this. I haven’t had a single issue with it. Make sure to use the sealant to cover the solar panel feet and I suspect you’ll be fine. We’ve been fine for 35,000 miles!
Q: Do I need to wash my panels?
A: Yes! After a few months driving around, I got on top of the van and the panels were practically coated in dirt. I’d say a solid wipe down every month or two would be a good idea.