Cargo Trailer 48V solar - for use when travelling and also at home

[AgileMIke]

Hello,
I'm very new to the forum so I thought I'd post up my proposed project and see if anyone has improvements to my system.

It's a weird system for three reasons:
1) I'm installing in on a 7x20 cargo trailer. I can fit (6) full size panels on it and I plan to build an awning that can be raised when parked for another (6) panels.

2) I'm wanting it to work when travelling and also when parked at home.
-The load when travelling is to charge one or two electric motorcycles. They each charge at about 15A @ 220V, however, we typically ride them for 20-30 minutes then charge them for 20-30 minutes.
-The load when parked at home is to charge a Tesla, which can charge anywhere from 8A to 30A @ 220V. I won't tie into grid when parked at home, just want to utilize the solar panels to charge something and don't want the hassle of a grid tie system. I will try to keep from using the battery when parked at home, as I'm worried daily charging/discharging of the battery will wear it out quickly. I can set Tesla charger to only charge during peak solar times.

I'm OK with the generator running occasionaly when travelling, which will happen if I can't get full sun on the panels or I'm trying to charge two bikes at once. We use the bikes to race motocross, so primarily using in the summer-ish months and most charging done from 11am-4pm.

I understand electricity enough to get all the wire sizing, connections, etc. Just looking for input on my selected components.
All-In-One Inverter : EG4 6000XP
Solar Panels : Rich Solar Mega 400W (or similar)
Generator : Ai Power GXS7100iRD (5.7 kW running)
Battery : EG4 LifePower4 (48V 100aH; will start with one battery and add more if generator runs too often)

 

[eXodus]

I had a similar idea recently. Want to tow a small electric car (BMW i3) behind my Class A RV and charge it somehow at home as well.

Aside of the Rich Solar Panels your plan looks like a solid one. You can get more powerful panels per sqft probably somewhere local.
In the same physical format as Rich Solar 80x40 inches - you can get a 550W panel these days. On trailer you want to have the highest performing panels you can get your hands on.

Battery - one will be likely not enough. That's only 5kWh.
You array will be somewhere between 3 and 6kW.

Rule of thumb You should always have at least double in battery what you have in array.

Otherwise your batteries are fully charged at 10am in the morning and no more storage available.

If you diligent charge during the daytime - it might work out for you - but if not all the solar energy will be not used.


Have you thought about how to construct the awning yet? I've been researching this for a while now.

I'm thinking about Piano hinges and air-springs (the same as in the trunk of you car)

 

[AgileMIke]

Thanks for the reply.

Very good point on the battery. I plan on purchasing another battery when I verify everything works well, as the batteries are $1250 each and I didn't want to spend too much money upfront and end up going in a different direction.

Also good point on the solar panels. I will see if I can get something more local in Boise or Salt Lake City area in the 550W size.

I haven't figured out the awning yet. I was definately going with piano hinges due to weight, but haven't really figured out the strut/raising system. It will be a little heavy with 6 panels and the frame, maybe around 300 lbs. If you figure out a good awning design, please post it in the forums.

The awning will be nice because it will work great for shade as well.

 

[eXodus]

One guy built this awning system - not as large as we are planning - but to bring the idea across.

You get those air struts with 100lbs lifting capacity - to have a spare capacity - just split they awning array in 2 or 3 panels each.

 

[eXodus]

Very good point on the battery. I plan on purchasing another battery when I verify everything works well, as the batteries are $1250 each and I didn't want to spend too much money upfront and end up going in a different direction.

true, you can always expand later. Just sometimes shipping costs make it more economic to buy two batteries at once. Depends on your choice of dealer.

Also good point on the solar panels. I will see if I can get something more local in Boise or Salt Lake City area in the 550W size.

550w is the current maximum in that form factor. (Canadian Solar, European and US Maker) You might not find them, but definitely more then 400w. I got 4 year old panels on my RV which have 445W in the size of Rich Solar 400 and even the cheaper Asian brands have above 480W for the same sqft.

For the awning Array - Bi-Facial Panels would be interesting. Even more harvest at odd angles

 

[rustylidoffroad]

Love this thread. I'm planning on something similar. I have an 8.5x20' trailer. Looking at doing 6x bifacial renogy panels (decent prices right now). Exploring a "simple" battery/inverter solution with the battery evo Walrus. (seems too good to be true) but I love that it is portable. Any thoughts? 13kwh battery, 8kw inverter, charges PV, AC, DC. Breakers, outlets, NEMA 14-50 stuff. seems like it checks a LOT of boxes.

Plan... Use the solar and battery to charge our EV cars when parked at home. (I'm CA and have a small 3.75kw NEM2 system currently, and have no real good solution to upgrade without crazy expenses due to PGE). I'm building an electric WWII jeep, so I plan to be able to charge it up when I tow it on trips in the trailer (a few times a year). Most of the time the trailer would be in the driveway, and I'd be charging our Model Y or Rivian R1S via the ~3kw solar system and the 13kwh walrus battery.

I like the idea of the Walrus being a generator in the case of an outage. ie. I will upgrade my panel with a manual generator interlock kit (or automatic, please share recommendations) so that I can leverage the walrus for whole house power the few times of the year I need to.

While it'd be cool to have a hybrid inverter and be able to grid tie... the cost and ease of not needing permits seems real nice with this being all off grid and usable in emergencies as a generator.

Open to suggestions on attaching the panels to the trailer roof. I'd like to avoid leaks. I'm also going to be researching to make sure ~320lbs of solar on the roof will be okay.

Not trying to hijack the thread, sharing my deal in case its helpful and to keep this thread moving along.

Thanks!
-CJ