I've been looking for a panel for the 17 ft. Boler
and came across this source in Cambridge, Ontario.
12 Volt Solar Charging Kit - Cambridge Parts, Accessories For Sale - Kijiji Cambridge Canada.
This is the same charge controller I have in my 13 ft. trailer while the panel has 40 more watts of power than my two panels on the 13 ft. trailer. The price is about 2/3 less than what I paid a few years back so prices have dropped considerably. This MPPT charge controller is practically bullet-proof. Mine has performed flawlessly and I highly recommend it.
The difference with this system is that it will charge at 12 volts (18 actually) while the panels on my 13 ft. Boler
are wired in series to charge my battery
at 24 volts (probably 36 volts). (I haven't kept up on my solar
terminology so I may be mixing up my terms a bit) This allows use of smaller gauge wires but in practice, it doesn't matter much in these little trailers. Wire this in with 10 ga. wire and you will be hard pressed to draw your batteries down if you are set up with LED lights
and don't use major appliances that draw a lot of amperage. (ie: don't use a hair dryer, toaster or microwave
with your inverter)
The main disadvantage with this particular panel is its physical size of 58 X 39 inches. Hard to get on the small trailers. I can make room on the 17 ft. Boler
by re-positioning one of the roof vents. Easy for me to do right now as the trailer is gutted. Perhaps not so easy if your trailer is intact. Its' weight
is 46 lbs.
Grade "B" panels contain cells that have slight defects such as chips or discoloration. According to my research this does not affect their output much.
The panel alone sells for $1.65/watt (Canadian). Taxes, duties and shipping extra.
I've researched costs for making my own panel and can't come close to this price taking into consideration the time it would take me to put the panel together.
If you are in the USA you could probably make one cheaper as most suppliers supply free shipping within the continental US. Unfortunately we Canadians get dinged for shipping which ups our costs.