24V Growatt system design for travel trailer

[pactolus]

I have found the resources and input from members of this site incredibly helpful. Thank you all for sharing your knowledge.

Based in large part on what I've learned here, I think I've just about finalized the design for a solar electrical upgrade to my travel trailer. The RV came equipped with a 190-watt GoPower solar panel module and a PWM charge controller. I plan to replace the charge controller with a Growatt 24V SPF 3000TL LVM all-in-one, assemble a 24V/230Ah LFP battery, and add solar panels and a step-down converter.

Before I move forward with purchasing the necessary components, I am submitting my proposed design for your collective input and wisdom, for any of you who might be willing to offer any suggestions or constructive criticism. Thank you for your help!

 

[12VoltInstalls]

Curious why your 12V loads go to chassis ground versus the negative bus bar. That’s one thing that’s sticking out to me.

The other thing that’s not clear is if the growatt negative to the buss bar is just the growatt ‘case’ ground or if it’s a ‘second’ ground wire (the bare/green) that goes to the AC distribution panel.

 

[pactolus]

Curious why your 12V loads go to chassis ground versus the negative bus bar. That’s one thing that’s sticking out to me.

Thanks so much for your reply and time looking at this. The reason for the 12V loads using chassis return as a negative is frankly because that's how the trailer was built. In the OEM configuration, the only connections to the negative battery terminal are to the frame and to the charge controller. So I believe all the load negatives connect to the RV frame either directly or at the fuse box. It works, so I didn't intend to rewire that (although I now plan to have a negative bus bar between the battery negative and chassis ground).

The other thing that’s not clear is if the growatt negative to the buss bar is just the growatt ‘case’ ground or if it’s a ‘second’ ground wire (the bare/green) that goes to the AC distribution panel.

The black 2AWG cable from Growatt to negative bus bar is the Growatt's negative DC cable to battery negative. Best I can tell there is nothing in the Growatt manual regarding a case ground to the RV chassis or battery negative aside from the main battery negative cable. I am wondering if that is something I should add.

On the AC side, I plan to cut the Romex leading from my RV's 30A AC shore plug to the AC distribution panel and add my Power Watchdog on the plug side. I will then run triplex cable (including ground) from the output of the Power Watchdog to the AC input of the Growatt, and from the Growatt AC output back to join the severed Romex leading to the AC distribution panel. When connected to shore power, I believe the Growatt will be grounded to earth ground via the green wire in the triplex/Romex/shore cable.

 

[12VoltInstalls]

works, so I didn't intend to rewire that

I’d homerun to the busbar if it were me

there is nothing in the Growatt manual regarding a case ground to the RV chassis or battery negative aside from the main battery negative cable.

Probably shouldn’t add one imho

When connected to shore power, I believe the Growatt will be grounded to earth ground via the green wire in the triplex/Romex/shore cable

That sounds correct