new guy, building a solar setup for my RV

[JohnPsz]

I have been in the "planning" phase for about 3 or so years, and last month (April 2023) started buying the items for my build.

I have 1800W (18 100W panels) of solar panels sitting in my basement. A 3000W Inverter, 2 MPPT solar charge controllers, and a host of accessories behind my couch in my living room, 16 280AH LiFePO4 cells being charged and balanced in my dining room. At some point, hopefully later this month, this stuff might actually make it out to the RV.

The process will be documented and shared on YouTube, not because I get anything from YouTube, but it is the easiest way to share their projects with their school that gives them credit for home learning projects. I still have to read all the forum rules before posting the videos, but have a couple already in setting up the batteries.

I will attach my "plans", but these were based off of rough dimensions I found online for the products I intended to purchase, so will change when actually implemented.

 

[JohnPsz]

Here is the "planned" layout of the panels on the RV roof.

 

[chrisski]

Seems like a good start.

Seems like you have two SCCs, each set up with 900 watts of panels, 3s3p each.

I don’t know your inverter voltage. That is going to drive the wiring size. I do hope it is 24 volts or greater. I think it is because you mentioned an Orion, which I think is a 24 volt to 12 volt 70 amp converter.

I also don’t see fuses, perhaps one.

I use 4/0 wiring for my 24 volt 3000 watt inverter. I also use class T fuses which are pretty big, but can handle the arc a lithium battery can bring.

 

[JohnPsz]

Correct, we are going with a 24v setup, and are going to run 2 3s3p strings of solar, 1 string ro each MPPT 100/50. I too have 4/0 for the inverter which is a Victron Energy Multiplus 24|3000.

I made a little progress tonight.

 

[chrisski]

I do wish I had tapped my bus bar so I could screw in BMS leads. The BMS leads like to rotate when I torque the nut.

You do seem on the right track.

Each SCC could produce 38 charging amps under ideal conditions. On a 1050 watt panels I have on my roof feeding a Victron SCC, I rarely see 30 charging amps. Things like the air conditioner, antenna, or other obstructions tend to shade a set of parallel panels really cutting into production.

 

[HRTKD]

In your diagram I see two fans. That's good. The compartment is going to need ventilation, more than just passive ventilation. How are you going to turn the fans on/off?

Where is the Multiplus going to be located?

 

[JohnPsz]

In your diagram I see two fans. That's good. The compartment is going to need ventilation, more than just passive ventilation. How are you going to turn the fans on/off?

Where is the Multiplus going to be located?

The batteries and charge controllers are under our bed, in what's roughly and 2'X4' box 1' deep. The inverter is about 5 feet away, 8 feet if you count it in wire run length from the Lynx Distributer. This placement was mainly out of consideration for noise (not wanting it under the bed within inches of where our heads are when trying to sleep) and mounting for best cooling of the Multiplus (Vertical).

The fans, as well as the battery heaters, will be run off the Cerbo GX relays. I debated on the Lynx Shunt's alarm relay, which can be triggered based on battery temp, however I only get a single switch at that point, and get more relay options with the Cerbo GX. I'm also planning on Ruvi tags to track ambient temps both compartments. Also, I figured in the evening that there would be no incoming solar, and therefore the charge controllers will not be hot, and hope the fans would be off by the time we go to sleep, but put them on my side of the bed to be safe, lol...

 

[HRTKD]

I have two sets of fans connected to my Cerbo GX's relays. I'm using Victron temperature sensors, but I could have used the RUUVI tags as I have a set of them.

My Multiplus 12/3000 is pretty quiet. I don't run heavy loads at night so sound at that time has never been an issue. But it isn't located right under my bed either.

With regards to your PV plan, my recommendation is to use fewer, larger panels. Less wiring, fewer penetrations of the roof, quicker install and potentially lower overall cost. My next install will probably use unistrut to mount the panels instead of the traditional Z brackets.

 

[JohnPsz]

I have two sets of fans connected to my Cerbo GX's relays. I'm using Victron temperature sensors, but I could have used the RUUVI tags as I have a set of them.

My Multiplus 12/3000 is pretty quiet. I don't run heavy loads at night so sound at that time has never been an issue. But it isn't located right under my bed either.

With regards to your PV plan, my recommendation is to use fewer, larger panels. Less wiring, fewer penetrations of the roof, quicker install and potentially lower overall cost. My next install will probably use unistrut to mount the panels instead of the traditional Z brackets.

Yeah I have unistrut with tilt brackets planned, I have never liked the idea of the Z-brackets.

 

[HRTKD]

Yeah I have unistrut with tilt brackets planned, I have never liked the idea of the Z-brackets.

Z brackets work. It's just more work than unistrut.

Unless the tilt is automated, I wouldn't bother. There are many implementations of manual tilt mechanisms out there on the Internet where the tilt was used the first few times and then never again.

 

[JohnPsz]

Z brackets work. It's just more work than unistrut.

Unless the tilt is automated, I wouldn't bother. There are many implementations of manual tilt mechanisms out there on the Internet where the tilt was used the first few times and then never again.

I agree, that in normal usage, I might tilt the panels maybe 5-10% of the time. I know climbing up there and setting things up will be a pain during most short trips and so forth, so I won't do it. However, in our case we also use our RV to go cross country and stay at my sisters farm for a few weeks at a time, or to my Father-in-laws farm for almost every holiday, and albeit I can moochdock and grab maybe 15 or so amps off an extension cord, I'd get the most benefit from the solar if I tilt them in those cases. The cost of the tilt brackets compared to conventional brackets and hardware was negligible since I got a great deal on the tilt brackets because they were too short for another person's project, but will work for my smaller 100w panels.

 

[HRTKD]

If you already have the tilt mechanism, might as well use it.