Did I get this right?

[SomebodyInGNV]

Please save me from myself.

I've collected the parts for my solar system and will start building it this week. (I'm waiting for delivery of the batteries.)

• Newpowa 180W 12V monocrystalline panels (Datasheet) in 2S2P array
• EPEver Triron 4210N MPPT SCC (Manual)
• SOK Battery 12V 100A LFP battery (Spec sheet) in 2P array
• Renogy 2000W 12V PSW inverter (Datasheet)
• Xantrex 15A inline transfer switch (Owner guide)
• WFCO WF-8955 converter/charger (Manual)
• Plus cables, bus bars, fuses, switches and breakers as appropriate.

My plan is below. I hope it's readable. I used a trial version of SmartDraw and have only 4 more days to use it. I can't generate a readable PDF because it's covered with watermarks.

This is the system I referred to in message 170644, here: PV array breaker/switch size? 720W of panels will lay flat on the roof and will be subject to shading. Wiring on the roof will be the 10AWG and MC4 connectors provided with the panels. I may need about 10' of extension. I'll get something ready-made with MC4 connectors, because the roof gland has them, as well. From inside the roof to the SCC (about 10') I'll use 8AWG. They'll be paralleled with an MC4 branch connector.

6AWG welding cable will be used from the SCC to the positive bus bar. It's the largest allowed in the terminal. From the battery to bus and to the inverter will be 2AWG. The inverter will draw < 200A at the rated current and 370A for a brief surge. The wire size calculator says 2AWG is acceptable for 2% drop over 6 feet (round trip) and 370A will result in a 5% drop. Being very short term, is that okay?

I'm using the OEM WFCO 3-stage lead-acid charger and will rely on the solar system to charge the LFP batteries completely. I'm replacing the ~20' of OEM 8AWG conductor from the converter/charger to the battery with 4AWG. I will replace the single conductor/chassis ground with both positive and negative conductors. The chassis grounds will be improved with 4AWG, as well. That and some new and existing 12V loads will be on a separate positive bus, allowing disconnecting the trailer from the battery while leaving the solar system engaged. The Blue Sea switch I have allows the converse, as well.

A Xantrex 15A ATS will be plugged into the inverter. I'll run 14/3 NM-B from the power center. One leg will be from the 15A breaker for the microwave oven circuit. I'll connect the return leg to the wire I pulled out of the breaker to make way for the 14/3.

I'm wiring the Renogy remote switch in series with the relay com slave module on the SCC. That way either the switch or the relay will cut off the inverter. The remote switch and the battery monitor will be in one place on the kitchen wall next to the remote display of my Progressive Industries EMS.

All suggestions are appreciated.

Edit: tweaked image and added color. No material changes made.

 

[Deleted member 9967]

I can't help you with your problem.
However, if you use "printscreen" then you can take a picture of whatever is on your screen and then save it without watermarks probably.
I hope this helps.

 

[SomebodyInGNV]

I can't help you with your problem.
However, if you use "printscreen" then you can take a picture of whatever is on your screen and then save it without watermarks probably.
I hope this helps.

I used Windows snipping tool with the same result. That's what I posted.

 

[Deleted member 9967]

Ah ok then. By the way.
The picture was not showing for some reason when I posted what I said. Interesting.

Ok then, you got this.

 

[SomebodyInGNV]

I was probably in the middle of uploading the improved (color) version.

 

[Deleted member 9967]

Ah ok then. I thought I did something wrong or screwy LOL.
Thanks, whew.

 

[Samsonite801]

...Please save me from myself.

...The wire size calculator says 2AWG is acceptable for 2% drop over 6 feet (round trip) and 370A will result in a 5% drop. Being very short term, is that okay?

...All suggestions are appreciated.

"Hear ye, hear ye, I hereby say that you're officially saved from yo-self brotha..."

Ok, now that that's all taken care of...

In the NEC (National Electrical Code) Fine Print Notes regarding voltage drops, it states a 5 percent maximum voltage drop “will provide reasonable efficiency of operation”, so I'd say your 5% for surging is just fine, it all depends on how much loss you're willing to tolerate within practical limits, it's certainly safe enough...

Really, the system seems to be fine for the most part.

Some people say it's a good idea to put a breaker on each parallel battery so if a battery shorts or draws more than the other one it can break off the bus separately. It can also give you an easy way to switch off one of the 2 batteries to make quick independent battery voltage checks if your trying to troubleshoot one battery pulling down the other one...

You'll have to assemble it and try it out for awhile and decide if it otherwise meets your needs well.

 

[SomebodyInGNV]

Some people say it's a good idea to put a breaker on each parallel battery so if a battery shorts or draws more than the other one it can break off the bus separately. It can also give you an easy way to switch off one of the 2 batteries to make quick independent battery voltage checks if your trying to troubleshoot one battery pulling down the other one...

Thanks for your review. Separate battery breakers would also require separate and equal negative cables to the shunt to avoid unequal resistance, no? That increases the amount of cable I have to buy and fit in my small space. I was going to use the Blue Sea switch (Off/1/2/All), which I already had, for that purpose, but it seemed like overkill? I had the switch for an earlier setup between two lead-acid batteries but, in practice, never used it.

 

[Samsonite801]

Thanks for your review. Separate battery breakers would also require separate and equal negative cables to the shunt to avoid unequal resistance, no? That increases the amount of cable I have to buy and fit in my small space. I was going to use the Blue Sea switch (Off/1/2/All), which I already had, for that purpose, but it seemed like overkill? I had the switch for an earlier setup between two lead-acid batteries but, in practice, never used it.

Yeah, like I said, 'some people say it's a good idea...'

The guy I bought my cells from recommended for me to add a separate breaker on each paralleled bank, and it makes sense to me. I just had a fellow shareholder from our coop ranch call me last weekend, and they said, something's wrong with my trailer RV battery, it will only charge up to 11.x volts and after all night it goes down to 10.5v... So I finally made it out last Sunday to look at it, and I manually took off the battery cables and check the 1st one, and it's 12.8v, then I check the other one and it was 10.5v (had a dead cell)... If they would've had circuit breakers on each one, I could've just had them turn them both off and check them over the phone for me, but they weren't that technical that I could have them pull off the cables remotely (worried they might short something out and burn the trailer down)...

It's not a critical thing, I just found it convenient the idea of having separate disconnects to easily pull the circuits open to check for an obvious voltage difference if you suspected some kind of imbalance in the performance between the two...