Here’s a description of our simple 12 volt power setup which we use while dispersed camping. There are definitely lots of fancy overland vehicle 12-volt power installations out there, and ours is not what you’d call “top of the line”. However, it gets the job done and even powers our small Dometic fridge/freezer. Our 12-volt camping power setup cost us just under $400 and includes two 100 watt solar panels, a solar charge controller, wiring, 12-volt outlets, a 122 amp hour deep cycle battery and case.
Update: Since this article was written we’ve had a chance to learn from some of our mistakes, and hence make some upgrades to our “budget”12 volt overlanding power system. We ended up switching to an MPPT type, Renogy dual-input charge controller, which precisely controls charging from both our truck’s starting battery – along with our solar panels. See our latest post here.
By controlling charge and discharge rates/levels we should be able to get a much longer life from our deep cycle battery. Our first battery bit the dust at just past one year and was replaced with the same wet cell Walmart model. A 100 Ah lithium house battery is next on the list – definitely no longer “budget”, but hopefully much more flexible and long lasting.
So far the MPPT charge controller is proving that it’s worth, and it’s handy to monitor our system via our smartphone, knowing at an instant if we need to move a panel or conserve energy.
Our Budget 12 Volt Overland Power System Install
The system’s main components are two 100 watt Renogy Monocrystalline solar panels, a Walmart 122 amp hour lead-acid deep-cycle battery, a solar charge controller and a Peak car-to-car 12 volt charger. The two solar panels are attached to each other with hinges, allowing them to fold up into a 43″x20″x4″ rectangle that we carry on top of our tonneau cover. (Update: We switched these out for two flexible Renogy 100 watt panels.)
The battery is housed in a plastic battery box which sits on a rubber mat in the truck’s bed, attached to 4 cargo tie-down hooks by two heavy rubber bungie cords.
There’s no direct connection between the auxiliary battery system and our truck’s battery; however we can charge it while traveling down the road by plugging one end of the Peak car-to-car charger into our vehicle’s power outlet, and the other end into the outlet that runs from the deep-cycle battery into the cab.
We run power from the deep-cycle battery into the cab using a fused pair of 12 AWG wire, wrapped in a plastic sleeve, through rubber grommets that line the holes cut from the bed to cab. Also, we added a 12 volt power outlet and USB charger port near the tailgate for convenience. We placed these two wires inside a plastic sleeve and fished this along the hollow truck bed walls to the tailgate. The power outlet near the tailgate has a voltage monitor, which is easy to glance at and check battery status.
What We Power With It
With this setup, we power a Dometic CFX-28 fridge-freezer, charge our phones, and run a small string of LED lights inside the tent. The Dometic fridge draws 1.75 amp hours, which, along with charging phones, etc., will draw the fully charged deep-cycle battery down to 50% in about 24 hours, if not replenished by solar. Keeping the battery topped off with the two 100 watt solar panels on our last trip was fairly easy and we always had more power than we needed.
How Well Does it Work?
We used this setup on a month-long trip that we took through Arizona, Utah, New Mexico and Colorado, where we dispersed camped on BLM and National Forest land. We were able to have cold drinks and keep food cold for up to 5 days at a time, without starting our truck’s engine once.
During the time we spent Grand Staircase Escalante National Monument in June, there was no problem getting enough solar power each day to run the Dometic fridge at 33 degrees F and charge the battery. It was also nice to be able to charge phones, run LED lights, etc., without worrying about running the truck’s battery down.
Some Things That Could Be Improved On
There are definitely some things we could have done better, while still keeping the cost under $400. We could have used a less expensive Renogy Wanderer PWM charge controller – costing about $30 – instead of ours that cost $60, and which had features we didn’t need. Also, our charge controller isn’t water-resistant, so we have to keep a plastic cover on it.
Any savings from using a cheaper solar charge controller could have been used to upgrade to a more rugged, sealed AGM battery, which would last longer and be more reliable than our WalMart special.
(See update at top of article) – We also could have upgraded to a more expensive kind of solar controller, called an MPPT model, which cost $60 more. Because of its increased charging efficiency, we might have been able to eliminate one of the solar panels. Our Dometic 12 volt fridge draws about 42 amp-hours, every 24 hours. If you add in another half amp-hour for charging phones, etc., we need to generate about 54 amp-hours a day to stay even, plus a little more to make up for internal battery drain, etc.
If we only had one 100 watt solar panel, ideally it should be able to produce what we need with about 8 hours of direct sun each day. Using only one 100 watt solar panel would probably work fine, but only under optimal solar conditions, as we had in Utah.
It would also be nice to have a properly wired and isolated vehicle battery-to-auxiliary battery charging system, which we didn’t have to plug in and unplug when we travel. We’ve priced the cost of wiring, etc. to go from the battery in the truck’s bed, all the way to the engine compartment, and it’s not cheap. For now, the simple little Peak car to car battery charger that we picked up on online for $30 works just fine.
(The other good thing about this simple charging setup is that it works both ways. If we ever run our truck’s battery down, all we have to do is swap cigarette lighter plug ends and charge it up from our deep cycle battery.)
Is It Worth All The Expense and Trouble?
If you’re only going camping for two or three days, a Yeti cooler and some ice will probably work great. You can charge your phone and other electronic items with your vehicle’s battery, if you start it up every now and then. For most people who go on short camping trips, an auxiliary 12 volt power supply and solar panels setup like ours would be overkill, not to mention an unnecessary expense.
If, on the other hand, you like to go off the grid – to your favorite high-country fishing hole, perhaps – and stay there for a week or so, then having a 12 volt fridge/freezer allows you to store the fish you catch, keep your beer cold and even have steak for dinner on day 5 if you like. Having a constant temperature fridge or freezer can also allow you to preserve leftovers, saving on food cost. Can you get by camping for several days without all this? Sure, but if you’re like us, having a fridge/freezer system that offers these benefits is well worth the trouble and expense.
To make myself feel better about spending the money, I divided the cost of our fridge/power setup by the cost of two bags of ice at our corner store.
Doing the math, we only have about 150 more camping trips to go until we get all our money back!
Please note: This is an old post. See updated post on our 12 volt system here.
