Start of RV build thread and intro long winded

[Lethenf]

First post from me this has been a wonderful resource for learning. Want to make this somewhat of a build thread. With the width and depth of knowledge available here hoping to get any insight I can.

Wife and I are in the process of rebuilding 2002 38' 5th wheel. Nearly a total rebuild from water damage. Have re insulated with foil faced EPS 2" plus air gap in the walls 3" to 4" plus air gap in the ceiling. So from r5ish/ non existent all around to r12 ish in walls and between r18 and r24 for the ceiling

The physical structure is nearly complete and I'm wanting to address electrical issues before I put all the interior walls back up.

When I bought the trailer it had a FLA 6v battery that was bone dry no voltage wired in parallel I thnk with a 12volt AGM battery that showed 11.1v. Thankfully both batteries were fairly new and I was able to swap them out for a matched pair of new AGM 110ah 12v for $68 for now. Will be swapping to LFP with Michael down the line once I can get a baseline energy audit done.

The hydraulic pumps for the slide and the leveling jacks both seem ok.

The A/C unit control board "functions" eg lights come on but doesn't seem to actually control the rooftop unit. It cycles on and off on its own no matter where the switches are set, so fried i think. Anyone have a particular stand out A/C unit/s they'd reccomend? Currently using one of the crappy 9kbtu portable units from my shop its enough to take the edge off but not enough to actually keep it cool.

The 45amp converter seems to max out at 20ish amps. When I attempt to pull more the lights start to pulse and fans get slightly odd. Unsure if its a wire size issue, if the converter is about shot from trying to charge a 9v? Battery or both. Basically i can either charge batteries or run lights and fans but not both.

To cap it off the smoke, CO, and LP alarms were all unplugged assuming the weird voltage from the 6v/12v combo they constantly would go off.

The 3 way fridge does operate in all 3 modes.

The oven functions but pilot light has to be manually lit. Same for the burners the spark ignition doesn't work but can be lit with a grill lighter.

Any one think of any other control boards/ or functions I ought to go test? Last 2 I havent tested are the water pump and hot water heater waiting on some PEX fittings to come in so I can flush the whole fresh water system then test.

For air flow the original trailer had 5 unpowered roof vents and the range vent. Have switched to a single powered one in the bathroom with plans to switch to 2 additional powered vents in the "garage" and the master bedroom. Think I will be ripping out the other 2 vents for additional solar space. I have added 3 8" radiator fans in one of the former compartment doors on a dpdt switch for additional venting either in or out. To any offgridders or RVers are the fantastic fans really worth that stupid high $$$ vs me slapping a $40 14" radiator fan up top.

My kwh meter should be in today so I can start doing an energy audit for solar and battery sizing. Can't wait for this part to get rolling.

The 4kw onan gas generator ran at some point in its life its up for testing sometime this week if I ever finish building the new countertops.

TL:DR for today
Hi
what all may be damaged in an RV 12v system that was attached to a 6v and a 12v battery wired in parallel.
Any offgrid/boondocking experience/advise is very welcome.

 

[cass3825]

First off, welcome! Sounds like you have the worst behind you, now it's time for the fun stuff. I'm sure you've read them, but @Lt.Dan and @cinergi have great threads on their RV builds and will also likely have some great advice regarding pitfalls to watch out for.

 

[Lt.Dan]

Sounds like a fun project! We need pics!

 

[cinergi]

While you have it torn down you might seriously consider mini-split for A/C especially if you want to run A/C from solar/battery. It's nigh impossible with the standard rooftop RV A/C units. And the more insulation, the better.
3-way fridge? Dump that for residential fridge if you're going to run that off solar/battery, too.
Measure your peak 12v usage (e.g. running the jacks) in case you decide to run a 24 or 48v system and need a DC-DC converter.

 

[Lethenf]

I'll upload some pics soonish up my SO has been documenting on FB. I'll have to work out some hosting.

I strongly debated the mini splits unfortunately with it being a toy hauler the entire back wall drops down so that mounting point is out. The front wall above the pin box is strongly curved >30* and the front behind the tailgate is my 12v battery access, my generator, and my landing jacks access. All the minis I've looked at if I were to side mount puts me over max legal width. So I dont have a lot of choice for mounting. They are pricy but looking into the 12v and 24v compressor roof mount A/Cs that a bunch of the sprinter/transit/vanlife folks are using. I have measured it out with a bit of cutting and reinforcing I could use one of the through wall/window LG inverter A/Cs in the master bedroom just a bit of extra sealing on the exterior.

Fridge, SO and I were talking about that today going to run off propane for the time being till the rest of the remodel is complete. I'm torn between the DC native (god are they expensive), and the residential. We're already planning to run a res chest deep freezer. Currently we generally buy what fresh we can in bulk vacuum pack and freeze. Literally all thats in our sticks and bricks fridge is condiments, mixed greens salad, a pitcher of tea, and 2 defrosting meat options for tomorrow and the next day. That being said strongly considering going to a chest freezer converted to a fridge or a sub 4cuft dorm fridge and up insulate the exterior.

Planning to run both 12v and 24v. Have to keep 12v anyway for the breakaway brakes might as well use it and what stock wiring I can. 24v for the solar and inverter, 12v for lights, fans, phone/speaker/aux battery charging, water heater, water pump, and backup for current fridge.

Current planned setup 8s2p 3.2v 170ah and 2p 12v 100 AH AGM for 24v and 12v respectively AGMs being replaced with lithium cells once I figure out where to drop ship them 45 to 90 days in the future. Also likely adding 2 more parallel 24v strings in the same drop shipment. So will take the 170ah cells to 4s4p and new cells 2xx AH 8s4p Moving the lead acid AGMs over to the truck box on a trickle charge from the alt for backup.

Things I'm currently debating go full 24v solar on the roof with 8 panels or split it 6 24v panels and 3 or 4 100w eclipse panels at 12v. Already planning to use multiple SCCs and a 24v to 12v victron converter. The smaller panels "could" give me more WH at triple the cost/whr but higher efficiency and work around a roof cutout that I probably can't eliminate.