Multi Plus II

[xxn5ac]

I realized that my solar panel picture didn't show the actual mounted panels, but where I had placed them before mounting them. Here's a few mounted pictures. Here's looking forward from the back of the trailer:



Here's looking backward from the middle of the trailer. You can see a bucket with the Texas flag. I used a pulley from the metalwork over my trailer at the storage facility and some nylon cord to send that bucket up and down to my wife who fetched me tools, sealant, fasteners, etc. as I needed them:



I used the standard MC4 connectors and purchased a crimp tool for them. Once you get the hang of it, they are incredibly easy to use. On the left of this next picture, you can see the panel that came with the trailer. I removed the roof penetration placed by GD and put in my own that I could use to send more wires down to the bottom. Sending extra wires to the basement was probably the hardest thing I did. There was a right angle not too far from the roof and it was a real pain to get the fish tape to make a right turn and then pull the wires down. I sent the fish tape up with GD's original wires and then back to the basement with theirs and mine. For my panels, I did a (2S2P)2P install (8 panels) and the 2P wires went down separately and were combined at the MPPT. This was to reduce the voltage drop by 1/2. The 2S means that the voltage going to the basement was around 46V for my panels.

(this picture in next post ... only allowed 5 per post apparently)

This next picture shows some of the wiring connecting everything together. I used cable tie stick-downs to hold the wiring. They have double-sided sticky-tape on the bottom and a place for a tie wrap on the top:



I also bought a crimp tool for the wiring (all 1/0) and I used black (GND), red (12V) and yellow (24V) so as to keep everything clean. I already had a heat shrink iron and I used that to put heat-shrink on all the cables. I prefer the heat-shrink that has the adhesive on the inside. All the wiring is marine grade (impervious to oil, gas, etc).



For power to the system, I ran the shore power connection that normally goes to the breaker box to the MPII and then I ran a new run of cable to the breaker box from the MPII. As you can see, I built a wood shelf to hold the batteries. I wanted something that wouldn't slide around and would handle the batteries well. Since I had height to stack the batteries, I made it two level. It's just 2x4 and 7/16" plywood all screwed together plus some automotive battery tray with the screw-downs to keep the batteries in place. I used L-brackets to secure it to the floor. As you can see, I lifted off the floor by a few inches. This was to allow plenty of room for the two waste valves cords to lay just like the were. I didn't want to interfere with them.You can see one in the picture under the unit. The SmartShunt is on the left side of the battery box and has the ground wire running through it so the Cerbo GX can keep track of all current in and out of the batteries. Initially I did not tie all the 12V points of the batteries together. The batteries are in a 2S4P configuration and the red cables tie two 12V batteries together from right (0-12V) to left (12V-24V). So the red connection between them is at 12V potential relative to ground. I do have a midpoint monitor attached to the SmartShunt and the Cerbo was very unhappy that the voltage drifted around. I ended up tying all the 12V centers together and that all went away. Now the 12V is off no more than 0.2%.

[xxn5ac]

Here's the missing picture from the prior post:

Attachment 44677

[Brother_Bluto]

Someone asked to see pictures of the install. Here are a few. You can’t see all the panels because there are 1-2 behind me near the ladder. I have a total of 9 panels: the 350W that came with the trailer and 8x 200W panels I installed.

You can see a picture I took of the Cerbo GX in installed by the TV. This was a rather humorous thing that happened: my wife was warming something in the microwave, one of the kids had a hair dryer going in the bathroom and the A/CS we’re running. It’s not every day I see 6kW getting pushed through the trailer, of course!

I apologize that the pictures are flipped around. I’m posting from my iPhone and Apple loves to store things flipped. I’ll try to correct when I get near a computer.

Attachment 44636
Attachment 44637
Attachment 44638
Attachment 44639

Thanks - looks great, but I think Solitudes are a drop frame and therefor an extra ~1ft of headroom in the basement vs the 351M which makes a world of difference and opens up options for install.

[Rich38]

I am guessing that the way you have your batteries wired together is causing your voltage to sag, or, the internal BMS is limiting the amperage output of both batteries to just the output amperage of a single battery.

To fix this, you need to wire your batteries using a "Buss Bar" system (each battery is wired to a Buss Bar and the load is taken from the Buss Bar instead of the battery posts). When you wire your batteries to a Buss Bar, each battery can contribute 100% of it's rated capacity to the load, versus, both batteries being limited by the first battery in the parallel configuration.

Here is a research paper explaining why a "Buss Bar" system is better...

And here is a picture of the type of Buss Bar I am talking about...

Finally an update to my issue. Wired the batteries using the buss bar system and everything worked great. Thank You for the info.

Rich