Unorthodox solar panel install - 24 ft. RB

[Ray]

Tom - Pls check PM

[FrankGRUN]

I have been following this thread and thought I'd offer a few comments about my solution, as this is an unusual DIY topic for this board. In my case, I have a 1982 Born Free 24 ft. Rear Bath model. I had upgraded the power panel to the current Progressive Dynamics system but felt the single auxiliary battery (mounted under the hood, driver's side) was inadequate. I therefore enhanced the auxiliary setup by adding two Trojan 105's in a appropriately sized and sealed battery box. The box is sealed, vented to the outside and mounted in the storage area under the oven. The battery cells are watered with an automatic system. The batteries are wired into the Progressive's auxiliary circuit with 8-gauge cable.

I then added two 120W/12v solar panels on the slope of the roof just behind the highest point of the cabover bed section, and to either side of the ventilation fan. The cabling (all 8-gauge) was then run down the fridge vent, down to the underside of the body and routed over to the sink complex that contains the power distribution module. I used a Morningstar solar panel controller and wired the DC input into the appropriate Progressive terminal.

I adjusted the top of the leading edge of the solar panels to be at the same height as the top of the cabover roof. More importantly, based on my previous (before retirement) working experience, I contacted 3M for the optimal Velobond adhesives and glued the mounting pads for the panels to the roof top, thereby eliminating any holes through the body in the installation. The adhesive prep just involves careful cleaning and wiping with a chemical priming pad. Also using the Velobond adhesive approach, I added two 1/16" thick Aluminum strips the width of the solar panels from the front edge of the panel to the cabover roof surface to minimize possible buffeting turbulence at the panel edge.

This was done in the summer of 2011. In the intermim we have logged more than 20,000 miles including an 8,377 mile cross country tour this past fall and the solar panel mounting is just as rigid now as it was when installed. The system has been exposed to temperatures ranging from 107 to -12 degrees Farenheit as we winter in Reno, NV. These temperature excursions were enough to warp the cabover pexiglas window, breaking the seal and necessitating a trip to the factory for a costly repair.

The addition of the panels has maintained our three battery auxiliary system at full charge through evening lighting, furnace operation, multi-hour TV viewing, stereo operation, laptop operation 24/7, and inverter operated hair dryer use. They have maintained full charge of all vehicle batteries during winter storage even though the BF is stored in an outdoor covered facility that keeps the panels shielded from direct sunlight. Best dry camping investment I ever made. I spent $115 each for the panels, $40 for the controller, $35 for the adhesive.

Hope this helps someone! Sorry for the length.

[stevek]

Good info Frank. Thanks.
I choose the portable option for now.
I bought 2 -105 watt panels from Home Depot and HINGED then together.
And carry them inside, behind the side flexsteel chair next to the door.
That way we can park in the shade.
Total cost was maybe 350 bucks including controller and wires.

Mostly we stayed at fee parks, so electric included.
But when we boondock, and stay at USFS campgrounds, I take the portable solar.

Eventually would like to mount a panel on the roof. But will continue to use the portable solar.

[tanksalot]

Frank:

Thanks for posting! I appears that something in the neighborhood of 200 watts is adequate, from (mostly) your experience as well as mine so far. I've seen quite a few large trailers, mostly in Quartzsite, that have 3-4 large panels angled toward the sun and can't understand why they'd need so much energy. My Trojans are staying fully charged and we don't scrimp at all on electricity usage. We only use the generator for the microwave and hair dryer..

Prior to putting up the panel I was quite concerned about the effects of the wind, possibly lifting the panel and roof rack or weakening the structure. I mounted a piece of cardboard the size of the panel with duct tape on the roof rack and had my wife drive by at 60 MPH. The net effect was the cardboard was pushed DOWN from the air going over the a/c. So far so good.

I'm glad I went with the permanent mount. Continuous charge on the coach batteries, no theft worries and one less thing to take out/store/set up etc.

By the way, how did you set it up to charge your vehicle battery as well? That would be terrific for when we leave the camper for months at a time.

Tanksalot
Stan F.

[FrankGRUN]

Stan,

I agree on the adequacy of 200 watts. As I indicated, my very much older BF has an auxiliary battery, same size as the starting battery mounted under the hood. I use a 12v deep cycle Interstate battery in this location. That deep cycle 12V is wired in parallel with the two 6V 105 Trojans for my auxiliary battery system. Of course the two Trojans are wired in series to give the effective large capacity 12V battery pak. The whole auxiliary battery system is charged by the Progressive Dynamics charger when on shore power. But at all times the aux battery system is connected to and charged by the Solar Panels through the Morningstar Solar Panel Controller. In all of our travels, 200 watts without optimizing orientation has proved to be more than adequate for all of our heating, lighting, entertainment, ventilation and computing needs. I do not use high amperage inverters, and do not operate the Air Conditioner or microwave on battery power, but rather leave those (along with She-Who-Must-be-Obeyed's hair dryer) to shore power or the generator. For full disclosure, all interior incandescent lights have been replaced with LEDs, the computers are powered with high efficiency switching 12V suppiies and the TV and audio systems are all natively designed for 12v sources.

As for charging the main starting battery from the solar panel support system, I use a very well engineered coupling charger called Trik-L-Start ($50). It basically couples the auxiliary battery to the main battery and limits the charging current to 5A or less as needed. I found that there was a continuous current drain on the main battery of between 15 and 125 ma. Connecting the Trik-L-Start to the main battery has kept all batteries fully charged. When I originally designed the system and wired it up, I added an additional safeguard against main battery discharge by wiring in a battery disconnect switch for all loads going off the main battery. I then wired the Trik-L-Start to the main battery on the battery side of the disconnect switch. This turned out to be unnecessary as the photovoltaics were more than adequate to keep everything fully charged. BTW, the Trik-L-Start isolates the main battery from discharge through the auxiliary battery connection. Clever device!

I had also considered the portable approach, but, as demonstrated in our last multiweek excursion around the country, storage space is too limited in our BF to compromise the walkway and adding the hassle of setup and storage was just over the top. In my case, the under oven storage area is heavily compromised by the sealed mounting case for the Trojan batteries and the automated watering system. As a final point, I want to emphasize that at no time in our travels did we have to give any thought to orienting the BF in such a way as to optimize solar exposure. The efficiency of the panels and the Morningstar controller along with the capacity of the Trojans was far beyond the most extreme load our style of camping imposed on the system.

You can find the details for the Trik-L-Start and several battery protection devices at: LSLProducts.net.

[tanksalot]

Thanks!