Solar Panels for Footloose
Since Peggy and I are planning on spending quite a bit of time
"off the grid", I wanted to add some type of alternate energy source
to our system other than the 10 KW diesel genset that was already in the coach
when we bought it.
The roof on Footloose was also getting full and I only had a couple of places
left that I could install anything.
The BP Solar 85 Watt panels that I finally settled on actually provide more
power output per square inch than any other panel I researched. These are
Laser Grooved buried Grid (LGBG) panels that are supposed to be about 16%
efficient as opposed to typical 10-11% efficiency of other panels.
Since I have a 24 VDC house battery system, I had to mount two 12 VDC panels
in a side by side array so I could connect them in series for a 340 Watt 24
VDC array.
I purchased the panels, mounts and the Heliotrope RV-30SE Charge Controller
from Gregg Holder at Alternate
Means . Gregg has done a lot of research on RV Solar electric systems
and also conducts seminars on the subject
I mounted one bank (2 Panels) between the existing sunroof
in the bathroom and the sunroof over the refrigerator. The second bank was
mounted behind the rear air conditioner on the rear fiberglass cap. It looks
a little funny but works OK and I don't have anything shadowing either panel.
Greg's mounts are designed to tilt in any direction but since I stacked two
together, they will only tilt front-to-back in my application. I fabricated
some arms for them but may or may not ever use them.
I routed the 24 VDC output cable for the back solar panel array along the
roof and underneath the front solar panel array to the refrigerator vent where
it is paralleled with the 24 VDC output from the front panel array in a junction
box that I also purchased from Greg.
This is a covered box that mounts on the side of the refrigerator vent and
also provides for a feedthrough into the inside of the vent where the combined
output of both arrays feed the controller which is mounted in a cabinet immediately
above the refrigerator.
All of the cable on the roof is #10 gauge dual cable in a UV proof jacket
that I also obtained from Greg.
The line feeding the controller and the line from controller to the battery
bank are both #8 gauge stranded wire which I had on hand.
I have not spent too much time boondocking yet and the maximum
current output I have seen from the system to date is around 7.5 Amperes which
equals around 180 watts at 24 VDC. Since the controller is pulse width modulated
and will likely not deliver maximum current unless the batteries are pretty
low this is probably normal. My battery bank consists of (4) Trojan L16 batteries
in series. These are 350 Ampere Hour or a (24 x 350) 8400 Watt bank.
The batteries are also automatically charged by my Stat-Power
inverter and/or the engine alternator when on the road via a diode isolator.