If you want to run 120v appliances from your 12V battery, you’ll need a power inverter. But is that enough, or will you also need a battery bank in your minivan RV?
What about solar and a charge controller? I’ve used numerous set-ups in the odyssey camper and I may be able to save you some money.
Solar power has received a lot of press over the last ten years with the US government spending billions to fund development on, and hype the technology. Read any blog, Reddit community, or Facebook group about van dwelling, and it won’t be long before you see someone talking about solar. Adding solar to your van camper or RV seems to be THE thing to do and I’ve watched people spend $1000s on custom systems.
It’s not cheap to install solar and batteries in your minivan camper, with current prices running about $1 per watt and about the same per Ah of battery storage. But do you even NEED solar? I’m not asking if it would be nice to have, or even if you can live without it. Rather, I’m asking if it fits into how you intend to travel in your minivan.
On onboard 120-volt power system can be built one of three ways
- Inverter only
- Inverter plus batteries
- Inverter plus batteries and solar
I like to build things and so, I decided to try all three arrangements. I did them in stages, so I could build on the systems as I needed. I’ve used each configuration over multiple trips of two weeks or more. I’ll talk about the use case for each, but first, let’s cover some basics.
The Basics
If you are just starting to investigate installing solar on your van, you might be confused as to what all of the components do.
A complete solar system for your minivan camper conversion includes four major components:
- The Inverter. Your van’s charging system makes 12 volts (12V) of direct current or DC. Your household appliances use 120 volts of alternating current or AC. So, to run a 120V appliance, you’ll need to convert one to the other. That’s what an inverter does. It connects to a 12V battery and has a plug for your 120V appliances.
- A Battery (or batteries). The battery stores power for your 12V needs, including running your inverter. You can use the starting battery already installed in your van, or you can install additional batteries. These would be known as “house batteries”.
- Solar Panel. This turns sunlight into power. Even the best ones are very inefficient, but they can charge your batteries when there is no other source of power available, or when you don’t want to run the engine.
- Solar Charge Controller. This is a battery charger that regulates the power from the solar panel. It ensures that the batteries do not see too much voltage from the panels and that the house batteries are properly charged.
This isn’t a complete DIY, but I will put some Amazon links below in case you want to read up on the system components. All links go to stuff I’ve actually used.
Let’s look at the three ways you can have 120V in your minivan.
Power Inverter Only
One of the most popular additions to a campervan is the addition of a power inverter. Although there are 12v appliances available that connect directly to your 12V system, that would mean buying separate appliances for your minivan. Additionally, I’ve found that some 12V appliances don’t work as well as, or are less sturdy than their 120V equivalents. The former is especially true of the immersion water heaters that I like to use. The 120V unit boils water at a rate of 1 ounce per minute. The 12V version takes 3 times as long to do the same job.
So can you get by with just an inverter, powered by the starting battery? Sure you can, I did it on the phase 1 Odyssey camper conversion where I cooked with a 300W immersion heater. I traveled for weeks this way. You can safely run the heater for 15 min to boil water for coffee or cooking, without killing the battery. However, the starting battery in your minivan is not designed to provide a lot of power over time. It is also not designed for deep cycling. A deep cycle is where you deplete the battery more than 50%. Doing this can significantly shorten the lifespan of your starting battery or worse, leave you stranded. However, there is an easy fix for this complication—start the engine! That’s right, if you start the van and let it idle when you use the inverter, you’ll have a vast source of energy, limited only by the size of the gas tank.
I think this use case is perfect for a part-time traveler, who doesn’t want to spend a lot of money. It works especially well if you are moving every day because there will be enough juice in the battery to make breakfast before you leave and your travels will recharge the battery for the evening meal. Just be sure to drive long enough to replenish the battery, because the charging rate is much lower than the alternator’s rated capacity (5A of charging is typical).
If you want to see how to install an inverter in your van camper, check out this post
and this video.
Inverter and House Batteries
If your use case calls for being in one spot for a couple days and you don’t want to start the engine, you may want some extra battery power onboard. In this case, you would add a “house battery” or batteries. These are deep cycle batteries charge when the van is running. In this case, the house batteries are separated from the starting battery by a voltage sensitive relay (VSR). Also known as a “battery isolator” the VSR disconnects the house batteries from the starting battery during discharge, but reconnects them when the vehicle is running, to charge them. The better ones are designed to allow the starter battery to charge first. Here is an example of a VSR that is designed to operate this way:
You can also handle the disconnect duties manually, as I did, using this quick disconnect circuit breaker:
However you chose to separate the house and starter battery, this system will need to be recharged by running the vehicle (ideally, driving it for some time). There is one exception to this, which I’ll cover at the end.
Add Some Solar
I say “add some solar” because at this point the other components of your system are in place. All you need to add is a solar panel and charge controller for a complete off-grid system that does not rely on your vehicle to recharge it. The more batteries you have, the more solar you’ll want to add and so, this can easily become the most expensive part of your system.
It’s also where the marketers come in and raid your wallet. Brands like Renogy and Yeti are all the rage on the vandweller blogs and groups. This seems to be due to some blend of brand snobbery, along with ignorance of what is being purchased. It’s also sometimes the case that their Amazon link will earn them a higher commision on the $200 panel, even though it’s no better than the $100 panel. See my note on this at the bottom of the page.
For testing purposes, I installed a Renogy panel next to the no-name Chinese-made panel on my rooftop solar array (you’ll have to wait for the reveal). I suspect they all come from China, but it doesn’t really matter because they both had similar efficiencies and build quality. I’m convinced that the name is all marketing, but you are free to source your own panels and I won’t say you are right or wrong. I can only say what I found and in the words of Public Enemy…
So Do You Need Solar?
Well, that depends on your use case. I traveled for a long time with only an inverter in place. I probably could have done so indefinitely, however, I added house batteries and solar before setting out for RTR 2018. I knew that I would have to make my own power at RTR because it’s held out in the middle of the desert. However, I was unsure of how close I would be to other people and did not want to start my engine to recharge.
Another reason for me building a system is that 50% of this blog is DIY projects. Solar is sexy and so I thought it would make a good project. But do I NEED it? I’d have to say no. It’s a luxury that’s “nice to have” but is not essential. If the cost of building a solar battery system (a minimum of $300, but probably closer to $500) is keeping you off the road, I’d skip it. It’s not a necessary component in a minivan camper. The whole idea behind traveling in a minimalist fashion is to prioritize the travel over the luxuries. If you stop and think about it, adding an 8 Amp solar capacity (100W) is a bit silly when you have a 120 Amp generator under the hood.
It’s worth noting that you would not use a solar system to charge the starter battery under normal use. You COULD in a pinch, but since the battery is not meant for deep discharges, it’s best to use solar with a house battery.
External Power and Charging
Each of the use cases I’ve discussed so far assumes that you are camping in the outback, where there is no power. However, if you prefer to stop at campgrounds where there is power available, you can recharge your house batteries by plugging in to “shore power”.
In this case, you can run an extension cord to a power strip in your van. A small 12V battery charger (10-30A depending on your battery bank size) will charge your house batteries overnight. I sometimes do this if I am expecting to stay at a conventional campground that’s close to something interesting. I did this while camping at Devils Tower, WY.
The type of battery charger you use is not so important, as long as it is big enough for your battery bank. I use this one, but you can use one that you like:
Summary
If you are going to be spending an extended period of time boondocking, then solar might be right for you. If not…
Although it’s pretty neat to have your own self-contained solar system in your minivan RV or camper conversion, it’s probably the last thing you should invest in. If the whole point of going small is to go frugal, then having a solar generator system in your minivan is a little like having a 90″ TV in your bathroom. Cool, but unnecessary!
However, if you are a technology geek like me and want to build your own system, check out the list of DIY minivan camper conversion posts in the menu at the top of the page, for ideas. Whatever you do, don’t let the lack of a solar/battery system stop you from going out on the road. Plan to live out of your minivan, not IN it.
–Darren at OdysseyCamper
Note: I—like many other bloggers— use Amazon links on this website. If you follow these links, it won’t cost you any more, but I will earn a small commision on the sale. However, unlike some other sites, I ONLY post links for things that I personally use and find to be useful. I use some of the commissions to run the website and fund giveaways. Anything left over goes in my gas tank. Since I don’t rely on blogging to make an income (and most likely, neither should you) I don’t need to post links to the most expensive brand names, like SOME people do (not naming names…yet 😉