When I first started thinking about converting a van, one of the main things I wanted was power. Solar power to be precise, with batteries to store it during the day so I could have lights and more at night. From RVs to sailboats, this has become increasingly common. As such, there are a bunch of companies that offer everything from individual products to full kits with everything you need.
But what do you need? While thereâs a massive amount of information out there, most of it is for larger Sprinter van and RV-sized installs. For something small, more minivan sized, thereâs a lot less info. There are also certain expectations. Most notably that you wonât have a significant load since there isnât the physical space to have a lot of energy-draining devices. Thatâs fair, to be honest, but I wanted a fridge, lights, enough energy to charge cameras and a laptop, and ideally all that for a few days off the grid (or at least, not connected to âshore powerâ at a campsite).
Follow my travels on my YouTube channel and check out my book about budget travel, appropriately named Budget Travel for Dummies.
I also wanted what in my head I called âsignificant redundancy.â I didnât want to be constantly worrying about how much power I had in my batteries, or if Iâd run out if it was cloudy for a few days. In the end, my final build ended up being more than I needed. However, the price difference between that and a build with less overall capacity wasnât a huge difference (with one exception, which Iâll explain). So hereâs what I learned, what I bought, and what you might want to do instead if youâre building out a small campervan.
Solar Panels
Solar panels are surprisingly cheap. There are foldable/storable options, but I wanted to mount them on the van. One less thing to set up when arriving at a campsite. This would also have the advantage of charging while I was driving. The full-size panels like what youâd mount to a vehicle are generally in the 100-watt range, per panel. For your calculations, remember thatâs best-case. If itâs cloudy, rainy, etc, you might not get any power at all, or way less.
Some options have rigid frames, but there are also flexible panels that you can glue to your roof. I couldnât do the latter because of my panoramic moonroof, and because of some specific requirements that Iâll detail in the next article, so I went with rigid.
In the first example of going with more capacity than I would really need, I went with two 100-watt panels. I probably could have gotten away with just one, but given how inexpensive they are, I didnât see any reason not to get two. The biggest âcostâ would be the install in general, which Iâll get to in the next article, and having two panels instead of one wasnât going to add much.
Charge Controller
You canât connect solar panels directly to a battery. I mean, I suppose you could but itâs not a good idea. You need a âbrainâ to figure out what the batteries need. This brain is called a charge controller, and it goes in between your panels and your battery.
There are two types of charge controllers, PWM and MPPT. PWM, or Pulse Width Modulation controllers are older, less efficient, but cheaper. MPPT, or Maximum Power Point Tracking, is newer, more efficient, but more expensive. They do a better job regulating and adjusting the power between the panels and the battery.
Unless youâre on a very tight budget, you should get MPPT. The difference in price isnât huge, and the extra money is worth it in terms of efficiency and flexibility. Make sure you get a charge controller that can handle the power expectations of your system, which in fairness isnât going to be a lot for a minivan build. I went with a 20 amp model as it came with the kit I bought, which is plenty for 2 panels. If you have more panels youâll want a higher capacity charge controller. The price difference between MPPT controllers in this range is negligible.
Batteries
Batteries are the single biggest cost for a solar system. These might look like car batteries, but theyâre far from it. Well, at least most of them are. Their capacity is rated in amp hours. So if you have a fridge that draws 5 amps, and you have a 50 amp hour battery, then you can run that fridge for 10 hours. The three types are batteries are:
Lead Acid: OK, these are like whatâs in every modern car. They are extremely heavy, but the cheapest of the three options. Theyâre not really designed to do what weâre trying to do here, so again unless youâre on a really tight budget, youâre better off with one of the other options. One important aspect to keep in mind, you shouldnât let them drop below 50% capacity. As such, however much capacity you want for your system, you need to buy twice that.
GEL and AGM: These are sealed lead acid batteries that are more forgiving for campervan usage than repurposed car batteries. Theyâre more expensive than those, but much cheaper than lithium (which weâll discuss next). However, they donât last as long and have the same 50% issue of traditional lead acid.
Lithium: Lithium Iron Phosphate (LiFePO4) batteries are similar to what you have in your phone (lithium ion), except theyâre a safer, more stable design. Theyâre relatively lightweight, long-lived if you take care of them, and are designed to work with the drain-and-charge cycles of the typical campervan. Theyâre also significantly more expensive than the other types, however prices get better every year.
I went with lithium, which I donât regret, but I got two 100Ah batteries which⊠OK, I donât regret getting two but this was where my desire for extra capacity definitely cost a bunch of money. About 25% extra to be precise. Having used the system for months, even on days where Iâve used the batteries a lot, I have yet to fall below 60% of my system capacity. That said, itâs done and paid for, and itâs nice having the headroom to add more electrical devices without having to worry about running out of power in the middle of the night.
Optional Extras
For most builds, the above three items are all you really need. Solar to charge, charge controller to control, and batteries to store. You can power your devices either through the charge controller, or off the batteries directly.
I purchased two additional items that I thought I would need or want. Iâm not currently using either for different reasons.
DC-to-DC charger: If you want to be able to charge your batteries from your vehicleâs alternator, you need a DC-to-DC charger. I thought this would be a great accessory in case I was stuck in the rain for a few days and wanted to charge my battery. The back of my van has a separate fuse box, which made the install easy, and the trim level of my Transit Connect has a 150-amp alternator.
While I donât regret buying or installing it, I had a kill switch put in line which is currently set to âoff.â The problem, if you can call it that, is itâs pretty rare Iâd stick around somewhere if it was raining long enough to deplete my batteries. Also, itâs basically always running if the batteries dip below 100%. Thatâs as designed, and not an issue, but the panels themselves are also charging so it seemed a duplication of effort, and one that was reducing my fuel economy by some tiny amount. So this is nice to have, but in hindsight, definitely optional. At least, for my kind of campervan build. If youâre living in your van, perhaps youâd get more use out it.
Inverter: If you want to run standard household appliances, or you want to plug into power at a campsite or house, you need an inverter. This converts the AC power you get from a regular power outlet into DC power that your batteries and other car devices use. Itâs like a big version of a phone charger.
The problem is, scale that up to work with the above equipment, and itâs a huge and heavy device. While I could theoretically find the room in my van, I have yet to actually need it. My over-capacity design means I rarely use that much of my battery capacity, so I havenât needed shore power. I also hate cooking, and have found that a simple camp stove suffices for my needs instead of a hot plate and a rice cooker (which was the original plan). While I was hoping to go completely fossil fuel-less with this design (other than the vanâs engine), the infinitesimal amount I use to cook was likely less than what I would burn lugging around a heavy inverter. So, again, useful for some people for sure, but for me it wasnât necessary.
All told, I spent about $2,500 on all the above, including taxes. If I was buying it all now with what I know, Iâd skip the inverter and one of the batteries for sure, and maybe also the DC-to-DC charger. Thatâd put the cost around $1,100. This was all with Renogy, and the prices for all this equipment has fallen even since I started my build. I went with them because they had some good package deals, lots of info on their site, and helpful tech support. I paid full price for all the gear, they donât sponsor me or anything.
For more info, check out the video above. Up next, getting it all installed and running. Stay tuned.