RV system recommendations?

[SomebodyInGNV]

Hello. I'm a newbie and am accumulating material for a solar system on my travel trailer. I have an EPEver Triron 4215N MPPT controller, a QWork battery monitor, a cable entry plate with integrated MC4 connectors and 1' stub of 10AWG wire, plenty of 10AWG wire on a roll, and about 15' of 8AWG wire. None of the wire is UV-rated. I'll get appropriate cable, bus bars, breakers, fuses and other hardware as the need arises. I own a crimping tool.

My main goal right now is obtaining panels. The unobstructed and unshaded area on the roof is about 10' x 8'. Panels could be a little longer but the ends would be getting into a area where they might be shaded. They will be mounted flat and we frequently camp in the shade, so it seems like I should over-panel? I'd like at least 12" and prefer 18" of walk space down the middle of the roof. I'd like to install all panels once rather than install some now and expand later. I prefer panels with MC4 connectors so I don't have to do anything except attach them to the roof and plug them in.

I'm here looking for recommendations for sources of panels, suggestions as to specific panels to buy, and the recommended series/parallel configuration. Local solar installers aren't interested in selling to me. I have no qualms about recycled panels from reputable vendors. I live in Florida, so shipping from out west may be prohibitive. Specs for the controller are below. Further details are in link above.

Rated Charge Current
40A
Rated Charge Power
520W/12V
Max. PV Array Power
1560W/12V
Max. PV open circuit voltage
92V

My initial setup will be to maintain my current 2 x 6V GC2 FLA batteries with 215AH total capacity. I don't have an inverter and rely on the OEM (WFCO 8955) converter/charger, which is not Li-compatible, when on shore power. My power consumption is modest. We have a couple of CPAPs without humidifiers, LED lighting, 12V stereo, one Maxx-Air vent fan, and rarely use the furnace. We do want to be able to use the furnace on travels out west, though. We also have 12V chargers for a laptop, a tablet and a couple of phones. The refrigerator is propane with a 12V control panel.

After the controller and panels are in place and working, my future setup will include a LiFePO4 battery, a compatible converter/charger, a pure sine wave inverter and an auto-transfer switch to power a single 15A circuit. We won't use the latter for the microwave, AC or any heat-producing appliance. Most likely, it would be for a couple of hours of TV at night, and maybe a wall or desk fan. If I ever have to replace the refrigerator I'd get a 12VDC compressor model and increase the Li battery capacity if indicated.

Thanks in advance for sharing your expertise.

 

[snoobler]

Welcome.

You will want to limit your peak charge current to what the existing FLA permit. If no values are available, 0.1C is a good choice, so 21.5A.

While the WFCO 8955 may not say it's Li-compatible, it's voltages are certainly acceptable:

WFCO Technologies - Innovating the Future of RV Power

WFCO Technologies is committed to simplifying, enhancing, and optimizing every RV owner’s experience through advanced power technology and proven support.

wfcoelectronics.com

14.4V absorp. = 3.6V/cell
13.2V float = 3.3V/cell

It also has a very curious charge profile:

https://wfcoelectronics.com/wp-content/uploads/2019/06/8900-Series-Manual-web.pdf

page 7.

This might be favorable to LFP cells by not charging them to true 100% SoC (depending on your LFP capacity) thereby increasing their cycle life further.

 

[SomebodyInGNV]

Can you suggest which panels to use, and a source?

 

[snoobler]

21.5A * 12V = 258V. 300 min with 400W likely being okay IF you're getting your batteries fully charged before peak solar.

Since you want to install presumably more all at once, you either need to leave those over 400W disconnected or select a charge controller that can restrict current (Victron can, I'm sure others too, but I worship Victron).

Will lists several panels on his site:

Vehicle Mounted Solar Panels

Building a vehicle mounted solar power system? Check out my site. This page covers solar panels

www.mobile-solarpower.com

You need to evaluate your available area, the panel size, mounting method, etc. There are slight variations on panels that may make some fit better than others. Since shading is a non-issue, the bigger panels may work nicely. The only way you'll find someone competent to spec out a design for you is if they've already done exactly what you want to do on your rig, and that's not likely.

With 80 sq ft, the maximum possible solar you can have is about 1500W assuming you buy very efficient (20% panels). If you need an 18" gap down the middle, you're losing even more - about 1200W max. And of course this assumes you can utilize every square inch perfectly.

Another thing to consider is a partially deployable array, i.e., maybe parking in the shade is desirable for comfort... but that stinks for solar. You could have the same panels you have on your roof as a stowed deployable array - something you can setup quickly out in the sun while you enjoy the shade. If you go this route, it's important to make your ground array the same voltage as your roof array OR have them on a dedicated charge controller.