PV for a 30ft 5th wheel (photovoltaic solar panels on RV)
 

I am looking at various components for a 400W array to put on my trailer. Unless I am missing something it appears I have three options:

1. Buy a kit that is either overpriced and/or does not have the components I want.

2. Buy somebody's book that will tell me how to build a system ten years ago.

3. Seek answers on a solar forum from people that have trouble with Ohm's law.

OK, I'm being cynical, but the freely available information I am finding does not instill me with confidence. Can someone point me to a non-dealer forum where I can get basics and perhaps a little inside advice on products? I want four 100W panels with room for expansion, MPPT, and enough information on panel connectors so I don't end up having to hack things just so I can use my own wire.

Thanks;
Doug

First rule with solar is decide what you want to run and know how much energy it uses and how long you plan to use it.. Then we can help..

One microwave (1200W) for heating coffee, five or ten 4W LED bulbs, one computer hooked to a 32" flat screen TV two hours a day, 80W heater circulation pump (not OEM), a Dometic ammonia absorption refrigerator at 300W with unknown duty cycle. Power supplemented with a genset as needed. No air conditioning required.

400W is not optimal, it's what will fit on my roof. Our RV campground membership includes free electricity. The amount of solar/genset required will depend on how much time we spend boondocking.

12 or 24v batteries?

Four Trojan T105's in series parallel for 12V at 450AH. 24V wasn't an option due to existing equipment and the availability of 12V from the vehicle alternator. The inverter is a Xantrex SW2000

Solar 12v assist - EcoModder

There is a link for installing solar on a camper.

Use MC4 connectors. Any panel you likely buy will have MC4 connector ends.

Do you have a large battery charger for use with the generator?

Mine is 40 years old and not regulated. Do you have a recommendation? I've had good luck with most Harbor Freight stuff. Don't know much about their electrical devices though.

When I needed a larger battery charger I decided to go with 220 volt power and just built my own out of junk I had in my stash.
To control my home made battery charger and keep it from frying the battery I wired it into my 30 amp Morningstar PWM solar charge controller. (which the manual says not to do).

If you want to charge batteries that size in a reasonable amount of time you need a charger that will put out at least a good 20 to 30 amps.

Iota makes some nice chargers. They have an IQ version that is a 4 stage charger for running off of 120 or 240v. As far as charge controllers for your panels go I would stick with a small name brand charge controller. They are responsibly priced and will give you great performance. Some even have dumb load controllers so if your batteries get topped off by the sun it will switch the pv to a load of your choice ie a 12v heating element in a water heater if you have one. If you don't have panels yet renogy has 100 watt panels for 120$ shipped and that's one of the better deals I have seen for a name brand panel

Renogy has a few MPPT controllers as reasonable cost, though I did not find the $120 panels you mentioned. The Grape Solar panels sold by Home depot are a little more at $135 but I can get a replacement shipped to any store in the country if I have a problem on the road.

To help offset the system cost I was thinking of installing a preheat tank for DHW in my house and powering it with the solar array when the trailer isn't in use. DHW is a big expense for us, even in summer.

The trailer (2002) has a built-in charger though I have no idea how good it is. RV charge units seem to have a bad reputation among RV'ers for cooking batteries.