Tilted solar panels are one option to increase your solar harvest when living nomadically. This adds complexity and cost to your build, but you may find it a worthwhile addition, especially if you have high power requirements and want to spend time off-grid or in areas and seasons with low solar insolation. Solar panels must be laid flat when driving to avoid damage. The panels can be tilted up manually or by a motor.
Example build of power-tilt solar panels
The following writeup by Fred Bellows is used with permission.[1] The vehicle is a 2015 Mercedes-Benz Sprinter 2500: 170″ wheel base, high roof, extended length. Edited for length and to add links.
The new technology of higher performance solar panels, charge controllers, and lithium batteries, make it very possible to build an affordable, self-sustained off-grid electrical system. And unavoidably attractive to do so. – And so we did:
The idea is to fit as much solar on the roof as possible. Which is limited not only by how big the roof is, but by what dimensions the panels come in. I found two residential-type SunPower brand 325 watt panels that were 41″x61″ which worked well if I put them end-for-end. The roof is about 51″ wide, but I wanted two awnings and those were each about 5″ deep, so, it all worked out all right. AND! … I got them for free! It turn’s out that big home solar providers often have some warranty-replaced panels in the back of their warehouses that have only slight storm damage to their aluminum frames, and work perfectly, but they can’t sell them, and of course don’t want to destroy them. So, just ask!
You can’t really fill the ENTIRE roof with solar, because you need some room for the roof exhaust vents and a few antennas (there’s eleven on this van).
The other good way to make more electricity from a given amount of solar panel area, in addition to getting the highest efficiency panel you can find, is to have a way to tilt the panels up toward the sun, whenever the sun is low, like mornings, late afternoons, and all winter. This involves a stainless steel hinge on one edge of the panels, and lightweight aluminum tubing which is strong and doesn’t rust. All screws and bolts must be stainless steel, and adding tight fitting wooden inserts where bolts will be tightened keeps the tubing from trying to collapse or debilitate, possibly down the road due to vibration and stress. The ends of wood will be covered in SikaFlex sealer to keep the wood from rotting. I built the entire solar panel mount onto the awning mounts in order to not need any additional roof protrusions that could cause a roof leak. Then, you must decide if climbing up on your roof and unbolting one side, and putting sticks under them, are an adequate and acceptable way to tilt your panels sometimes for more production, or if motorizing is worth all the expense and hassle. For me, I found that it was, for a few reasons: A- I like to tinker and enjoy the design challenge. B- I decided it would be terrific if I could store some aluminum anti-gravity type chairs and a (custom, lightweight) cornhole game up there, and the motor would make that WAY more convenient. And, C- I already had the advantage of having two 8″ tall awnings and the solar panels were going to be 8″ off the roof, which made for enough distance to allow for an adequate angle of the linear actuators to not only lift, but hold-down with enough force to keep them from leaving the van dramatically at peak speeds/wind conditions.
These are the linear actuator motors that I used. They were $150 each because I chose the highest possible waterproof rating that states surviving “high pressurized water jets”, as I didn’t want to have to ever have them fail. They hook up to a simple momentary rocker switch, thru an additional safety power off switch. You’ll notice that I don’t have a roof air conditioning. That is in order to have more solar. I do have a custom made “basement air” configuration using a window AC that is detailed in its own section. It works even without being plugged into shore power or a generator because it is more efficient than an RV roof AC, and… I don’t have a roof AC,…in order to have more solar. And because of my “best possible” insulation, also detailed separately.
Here you see the back side of the panels when up. The two lounge chairs and the cornhole game stay in place quite well just sitting on a piece of closed cell foam padding. They get no sun, but a little wetness in a driving rain strom, but are each pretty much water resistant. You can imagine how easy it is for me to grab these down with my telescoping ladder. There is also enough room for us to sit on chairs up there, if we ever go to some event that makes that worthwhile. Since the entire ceiling was spray foamed, the roof is very rigid to walk on.
This video shows how the panels raise (or lower) fully in just about 10 seconds. The linear actuators only extend/retract with 12″ of travel, but that is enough for them to raise the panels to a little over 45 degrees of tilt. When the sun is low, as in the mornings, late afternoons, or all winter, there is a huge difference in power production with the panels up (up to 40%!), if the van is facing the right way. In addition to making it immensely easier to access the stuff stored on the roof with my telescoping ladder, another handy aspect of the motors is simple cleaning of the panels with my pole-mounted car washing brush when they are tilted up.
