25' Avion Trailer Solar Setup

[waterweber]

Im designing the solar setup for my 25' Avion Trailer and just want to run it by you guys for advice as I build it out.

I want to be able to run off grid as much as possible but not for extended lengths much past a few days.
I need to keep the trailer cool enough for my pugs in the summer down south so the rooftop AC will need to be in the mix.
I need to run the following: (im currently getting the draw for each item figured out and will update when i have that)

• Rooftop AC
• Maxxair fan
• Refrigerator (also runs an propane if needed)
• Normal interior lights etc.

Here's where I'm at so far:

1. I have room for 8 of the 195w Ecoworthy 12v panels.
2. Ill be building a rack system that is slighty raised above the roof to mount them on. Likey speedrail based.
3. Run them in 2 strings of 4 for roughly 48v @ 17 amps to the charge controllers. One string on each side of the trailer to reduce shading issues.
4. 1 - 3000w Ecoworthy 24v Inverter Charger.
5. 1 - Renogy 50/100 charger controller for the second sting.
6. Probably around 400 A/H of 24v batteries, Most likely just get these from Ecoworthy as well.
7. Ill need a 24v to 12v DC/DC converter to run to the 12v bank for the 12v stuff in the trailer as well.

Ill basically just grab the shore power feed and run it into the inverter/charger then output the inverter to the trailer side of the shore power. Then swap the 120v to 12v charger for the 24v to 12v converter to a smaller 12v bank.
I'll calculate the wire sizes, runs lengths and what ill need in terms of breakers and fuses once i get the basic design figured out.

Id appreciate an ideas to improve or gotchas that you guys see. Thanks

 

[waterweber]

Here's a pic of the trailer
I have since removed the TV antenna thing and will use that hole as a passthrough for the solar wires and a Starlink cable.
I've printed up a pretty cool pass through fitting that ill share a picture of shortly.
In the process of fully resealing the roof seams with Eternabond. I've removed the old vent over the bed and am replacing that with a Maxxair.

 

[HRTKD]

If your 24-12 converter can handle up to 30 amps, there probably isn't any need for a 12 volt battery bank. A trailer like that shouldn't have any heavy amp loads except for the tongue jack.

Since you're creating a rack for the roof, don't be afraid to let the panels hang over the edge a bit. I prefer large panels ( > 400 watts) over small panels. Play with the layout and see if they'll work out. The larger panels can often be less expensive than smaller panels. Large panels can be purchased locally, whereas small panels have to be shipped.

If you run the panels 4s2p you could get by with just one solar charge controller. There's nothing wrong with two distinct strings and two solar charge controllers. The main downside is you need to run four cables instead of just two.

 

[waterweber]

Thanks Jim,
I didn't think about ditching the 12v bank but I think you're right. the jack is definitely the biggest load.
Its not looking like i can get the bigger panels up there. I climbed up there with a tape and it just don't think i have the room.
I am planning to mount the panels at a slight angle and overhanging the side just a bit. With those EcoWorthy panels i will be able to run 4 longways down each side I think. If i get shading on one side of the trailer will i get diminished performance with the 4s2p setup? I know that i definitely would for the 4s part (if one panel was shaded) but I was thinking the 2p would suffer as well hence the 2 controllers. If that's not the case then i just run the combo inverter/charger.

 

[HRTKD]

If i get shading on one side of the trailer will i get diminished performance with the 4s2p setup?

Nope. Works just fine. It's often called an East-West configuration. Panels tilted East work great in the morning, panels tilted West don't do anything in the morning. In the afternoon that switches.

 

[0truck0]

The rooftop ac will be an issue for a couple reasons.
1. it is terribly inefficient.
2. is will shade the panels. Any shade will kill the panel, literally any shade, your hand, a single playing card...
Thus is good to have many sets of panels into many controllers (or one controller that handles many).

You want a mini-split for efficiency and that you can mount on the wall which will not shade the panels.
You can get mini-splits in DC versions, whatever voltage you want.
Sell the roof top ac, it is getting to the right time of year to sell it.

3, get rid of the rooftop ac.
4. I think I said that on #1,2 and 3, but for a reason.

5. forget roof vents. remove everything from the roof and put solar panels. Make vents on the sides or back wall.

6. you need more solar. you always need more solar. clear the roof for panels.

 

[HRTKD]

Furrion has a new A/C out last year that supposedly uses less power and is quiet.

Jared on the "All About RV's" YT channel covered it when he was at the RV show recently. They just now coming out available for retrofit on older RV's. They were previously only available on brand new RV's.

Solar Panel shading used to be terrible, it was all or nothing. Now, depending on how the panel is shaded you'll lose only a portion of the power.

 

[Scott SD]

For reference, I have a 24’ toy hauler with 3 different sets of panels on the roof (1300w) feeding 2 mppts. Also have a 300w ground mount with a separate Mppt. 2 200ah 12v lithium batteries in series for 24v. Mppts, inverter, and dc/dc converter are Victron. Soft start on the AC. No issues, works awesome, I haven’t used my generator once. As a note, I am not a fan of Ecoworthy, I had 2 panels that just never performed, replaced with Newpowa. Good luck with your project.

 

[waterweber]

Thanks guys.
Im not going to mess around with a mini split or removing roof vents. Mini splits are great but this is not the project for that.
Ill get by with the rooftop AC till i replace it later this year with one of the more efficient inverter based rooftop AC units.
The panels will be raised a bit so the shading will be minimal (only in early morning and late afternoon). This is the main reason I'm running 2 strings, one on each side of the trailer.

I may do a ground array down the road but I'm not living in this thing. Ill just run the Honda 2000 if i need a little more juice.

Thanks for the feedback Scott. Ill check out Newpowa. I was planning to go with Ecoworthy because i have an off grid cabin with a very similar system to what I'm planning for the trailer and its awesome.

Where did you get the soft start for the AC? Also what Victron inverter did you go with?

 

[Aussieguy]

the chill cube air conditioner is good
OR a Mini split

but you still need a huge battery bank

short falls with solar production can be made up with generator
mini splits or the chill cube that have variable speed compressors do not need a big generator / inverter

EVEN when they got the trailer down to temperature it will still consume around 400w
100ah battery will last about 2 hours

something goes wrong .. the dogs will cook inside a trailer
they can be happy with open windows and a lot of clean water

------------------------------------------------------------------------
I would stay at 2 strings of panels BUT for 12v battery
2 controllers for shade, 100/50 can handle 800w
each string 2s2p

separate controllers will handle shading better you NOT going to save a lot of wire for such small strings
volt/amps can be handled by 10g put the controllers next to the battery
10 to 8 gauge will handle 40v x 20amp
2 strings is better reliable power (redundancy)
price of second controller is offset somewhat by not requiring a 24-12 converter
if there is slides and other high 12v loads you may need a 12v battery as well as 24-12 converter

Inverter wiring is also no problem if you stay near the battery keep the distance short

 

[waterweber]

Thanks.
Ill either upgrade the the chill cube or one of the inverter based rooftop ACs that are coming out.
I have a Maxxfan installed and will do the window thing unless there is a serious need for the the AC in which case I won't leave the dogs in there unattended for very long.
If I did a 12v system with 2 controllers what inverter would you guys recommend? Do I also need a separate AC charger? Is there a good 12v inverter changer combo with 120v AC charging built in?
No slides in the trailer. The biggest load load will be the tongue jack.

 

[Aussieguy]

have a look at 370w panels
you can put two side by side mine were 40inch wide x 69Long
2 fit well together

I paid $175 each for mine Facebook Market place (no shipping)
740w = $350
ecoworthy 780w = $540

 

[waterweber]

If i run a string on each side I'm limited to about 30" width and total length of about 18'.
There is a larger open section in front of the roof AC and one behind, either of which i could put a bigger panel but its not big enough for the big 400w plus commercial panels.

 

[Aussieguy]

I'm happy with NO inverter
camp in spots based on weather

If I want A/c I pay for powered campsite

740w has worked well for me so far to keep the battery usage maintained
traveled 4000 miles without connecting converter to charge battery Northern Ohio to Everglades

MOOCH dock at relatives friends using a 15-20 amp outlet from garage
my trailer is stored at home connected to garage outlet and I can run the a/c 1300BTU rooftop
store it at thermostat 85 keeps Florida's wretched humidity at bay

 

[Scott SD]

I also recommend house panels if they fit. I used (2) QCell 365s, which came from FB Marketplace. I have found some awesome deals on Marketplace. My brother just bought LG 375s for $80, smoking deal.

When I designed my system, I contemplated 12v vs 24v, glad I went with 24v. Smaller mppts and cable sizing. I used a Victron 24/12 Orion, it is 70a, no issue to support all of the 12v loads.

I have a 24/3000 Multiplus inverter. The soft start is microair. Last year we were in the desert for 4 days, only needed the AC occasionally, I never unpacked my generator.

 

[waterweber]

You the man Scott

 

[HRTKD]

Figuring out how solar panels will fit on the roof is like a game of Tetris. Using a CAD tool to lay out panels is how I did it. I measured the roof and all the obstructions and plugged that into a drawing. Then created different sizes of solar panels to see how they would fit. I still had to be creative with how the panels were mounted to the roof, but I'm satisfied with the outcome.

 

[ghostwriter66]

The rooftop ac will be an issue for a couple reasons.
1. it is terribly inefficient.
2. is will shade the panels. Any shade will kill the panel, literally any shade, your hand, a single playing card...
Thus is good to have many sets of panels into many controllers (or one controller that handles many).

You want a mini-split for efficiency and that you can mount on the wall which will not shade the panels.
You can get mini-splits in DC versions, whatever voltage you want.
Sell the roof top ac, it is getting to the right time of year to sell it.

3, get rid of the rooftop ac.
4. I think I said that on #1,2 and 3, but for a reason.

5. forget roof vents. remove everything from the roof and put solar panels. Make vents on the sides or back wall.

6. you need more solar. you always need more solar. clear the roof for panels.

OR carry extra panels and mount them on the ground when you arrive ... there may be times that you are going to have to park under trees and things and having extra external panels to run 80m or so out to an opening is great ....

disagree with the mini-split ... maybe its just us but virtually all the mini-splits that we have put in our trailers has eventually needed servicing much sooner do to bumps and vibrations ... I know people hate to see these BUT a window unit is the way to go if you can fit one in ... we simply remove them when we travel and pop them back in moment we arrive ... I do agree with selling the rooftop A/Cs ... and cover the hole and add 40 pounds of caulk and that fixes your A/C sun blocking issues ...

and as stated earlier by others -- I love the 400+ panels -- so much more efficiency and less wires

 

[0truck0]

Did you use mini-splits meant for houses or for vehicles? That would be key, do include mistakes that you made when generalizing based on experience as that is very important for the reader.

 

[catfishtoon]

I have no answers for you but we full timed in a 34ft avion for 5 years. Loved that trailer. Pulled like a dream. Passed it down to our Daughter a few years ago. They for sure don't make them like that anymore.