Solar Power For 2019 RPOD 190

My wife and I purchased a 2019 model 190 a couple of months ago, and I'm doing some mods that I hope will add to the usability of the rig. First thing I did (from the dealer) was to replace the single 24-size battery with a pair of GC2 210 Ah golf cart 6V batteries in series. I had them add a double-tank propane bottle tray and a 2-tank regulator.

Now, I'm replacing the 8 AWG 12V wiring from the battery bank to the converter with 4 AWG wire running all the way back. The negative battery terminal is still connected to the trailer frame, but there are positive and negative 4 AWG welding cable conductors all the way to the converter. I have also replaced the WFCO 8735P converter with a Progressive Dynamics PD-4135KW2B unit.

At the same time, I'm running 16 AWG zip cord from the 7-pin "backup" wire to the back of the trailer.    I plan to install a pair of LED backup lights on the rear of the trailer and run a 12V line up over the rear window to power a Rear View Safety remote backup camera.

The next project is to install approximately 380-400 watts of solar panels on the roof and a 30A charge controller. The RPOD has a panel above the TV made of ridiculously flimsy 1/8" paneling which holds the switch panel and a "template" sticker for installing a GoPower GP-PWM-30 controller, so I will want a controller that's flush mounted. There are loops of 10 AWG red and black wire hanging down in that space I assume to be used for mounting the charge controller.

After doing some research, it looks like that there are a number of controllers which have a better reputation than the GoPower unit.

I'm writing to ask you DIY RPOD modders to share your experiences and recommendations regarding charge controllers. Should I get PWM or MPPT? It looks like most of them have several pros as well as several cons, so I'd like to have some input from others with solar in their 'PODs.

Thanks for any sage advice, gotchas, or other comments!
Mike Harmon, WB0LDJ

I recommend Morningstar charge contillers. I worked in solar for over 35 years and know the principal there well. Good stuff (I make no $ from endorsements).

As for MPPT vs PWM controllers, you should choose your solar modules first then decide. PWM controllers work fine for managing the charge from a nominally 12V solar module while MPPTs work by stepping down voltage from a higher voltage module to 12V. You can't really use MPPTs on 12V modules and you wouldn't want to use PWMs on higher voltage modules because the additional available voltage would be wasted.

The most cost effective way to purchase solar is to buy large residential or industrial modules. In the industrial size range (about 78 x 40 inches) you can get around 400 watts in a single module, and they are often available as project leftovers at around 50 cents a watt. Those run at higher voltages so you would need an MPPT controller for them. For the size of solar array you are considering that is the way I would go but you will need to carefully measure the space available and see what fits. It you end up fitting in a couple of 200-ish watt 12V modules in parallel a PWM controller will work fine, or you could wire them in series on the roof and use an MPPT if you wanted.

PS, don't get so-called "flexible" solar modules, they're not.

Cassandra, you can find leftover residential and industrial solar modules on Craigslist and eBay. Try to find something local, they aren't easy to ship as single modules. Also, think carefully about how and where you will be mounting it.

Re lithium batteries, they are great but require quite a bit of rework on your 12V electrical system. You will need a different ac to DC converter and also a dc to dc converter if you still want to charge batteries while towing. StephenH has done this and has a great write up in his mods you could take a look at.