34 ft Thor coach total redo AC/DC

[e67]

A relative of mine has this rig and is not capable of doing her own retrofit. Her RV system is 12v, is in- efficient ,convoluted, wires and boxes all over the place. Like any RV. She plugs in when she can and has generator and would like a solar set up. Her first Chinese junk solar system 100 watt got stolen. So she needs a Complete system and I think even a new DC or AC/DC fridge/freezer is in order.Not a Norcold factory box.
She is around the SE. USA most of the time. Full time RVr. She can only plug in about 25% of the time.I could do all the work but need a modular plan that I know will work. 48v DC solar maybe 300 watts panel system and 12v for some older 12v buss loads.Maybe 200 ah of storage. The generator is important. She needs some AC for health issues. But fans can do a lot.Cant and won't pay an overpriced tech to do any of it.
Where can I start?? I have unlimited time.

 

[Ranger Rick]

First, ask for her budget. The generator can be a back up if her upgrade includes a good inverter/charger. Watch videos on All About RVs, Explorist Life and DIY Solar. Research these forums. Start planning. Whether you go with a 48 or 24 volt system, there are step down DC to 12v DC converters. So she can keep the 12v lights and appliances. A good Inverter/ Charger should handle her medical AC machines. Generator is a good back up. Check out Victron’s MultiPlus-II Inverters and solar accessories. #1 Victron US dealer is Inverters R Us. However, air conditioning and boondocking will be the biggest challenge.
The price of copper is down 50% since February. Shop around online for pure copper wire/cables. With terminal or without if you’re a confident crimper. Residential solar panels are better than RV solar panels. Check with local dealers on open pallets and extra panels.
Don’t hesitate to ask. There are some really knowledgeable and helpful folks on this site.
PS check the thread below “Should I rewire? …

 

[jameshowison]

Take a look at the diagrams from explorist life, could be a useful starting point. https://www.explorist.life/solarwiringdiagrams/

Explorist life doesn't have a 48v version, though. What's the driver for that? He also is a batteryborn guy, but the server rack batteries should be a good starting point for you.

Map out the loads, especially the air-con. How many days does she need to be off grid with air-con, that can be a big driver of battery size. For example, in a small 19ft camper, with an efficient 48v DC air-con (Hotspot Energy) and temps in the 100° range we were running the batteries down by about 3-4kwh (ie over 300 amp hours at 12v) into the evening, the solar was usually able to replace that energy the next day, using about 1,240w of solar panels and full sun. If she is ok with only running air-con off grid by using a generator then that helps enormously.

 

[x98myers7]

unfortuantely/fortunately... the most informative RV solar YT channel recently changed. i think most of their content is pay only now.

https://www.youtube.com/channel/UCwzRwGEKZXPGwMDFzntfS0g/videos

Jared's channel is very good, as well. lots of electrical and solar.

https://www.youtube.com/c/AllAboutRVs

changing lanes, again great stuff from full-time RVers

https://www.youtube.com/c/ChangingLanes

 

[x98myers7]

I (personally) would go with a 24v system if you're planning to power AC on battery. many 12v appliances can run on 24v. IMO, 24v is best because DC down to DC is easy and you can get away with a lot smaller cabling at 24v.

mini-split systems are the best bang for the $$, however, unless you're doing the work for free, it probably isn't worth it to change from a roof-top unit. roof units are going to be 20amp+ constant load. in FL/south heat... you should plan for 25amps. I've never tripped a 30amp breaker even with AC on high. you'll need 3k watts constant with peak surge of 6k just for running and starting the AC. i hate the soft-start capacitor add-ons... waste IMO. just spend that $300 on a bigger inverter.

go with as big of a battery bank as you can afford. be mindful that some RV generator starters require huge amp loads to crank the generator over, and need very large lifepo banks to get enough amps. remember, the BMS in the off-the-shelf lifepo batteries will control the amps.... unlike lead acid which have no limit.

IMO, you might even want to consider keeping a lead-acid for generator starter.

 

[e67]

24v might be the better way...the EG4 Lith batt looks interesting. Would the BMS control the charging from the Motorhome alternator and the stock system still charge the lead acid start battery for the engine.?I will spend some money...

 

[chrisski]

I would tell her if Air Conditioning is a requirement it’s not possible.

I have a 35’ Rv, but I had to fill the roof with panels and put just as many on the ground and have a battery the size of a Tesla power wall.

People say mini-splits, but IMO a mini split on a 34’ RV with 240 square ft is not practical. Comes down to my 15k BTU does not work well for that size and mini splits max out around 12k BTU at 120 volts.

It’s not that what she’s asking for is impossible, but would cost as much to put her in an apartment for a couple years.