24V Travel trailer system check

[Jracine]

Hello everyone,

I am planning on a 24V system for a travel trailer and would appreciate a quick safety/any advice on changes. I think I have everything ironed out but I am new to solar stuff and I want to be 100% sure before I start buying components and I am open to suggestions. Thank you very much!

 

[MisterSandals]

Looks thorough. Nice touch with the precharge built into MP switch.

No generator?

When switching between battery 1 and 2, do you anticipate doing 1+2 in between? There might be a lot of amps if the batteries are significantly different SoC.

Or, going from battery to the other, will there be a battery disconnect in between? Not sure the SCC will be happy if pumping out a bunch of amps and have battery disconnect. Cutting solar likely a good thing is switching batteries. What will the rest of the system do with battery cut?

 

[Jracine]

Thank you!

No generator.

I anticipate staying in 1+2, and only disconnecting a battery if something goes wrong really or if I have to take one of the banks out. It just seemed like an easy solution for having options of 1,2, or both in one switch. How do most manage 2 or more banks in parallel if they have to switch from one to the other and there is an imbalance? I had not really though about that.

That switch is advertised as "Make before break" so it should make connection to the other battery before disconnecting the first so I would anticipate the system to continue to operate without interruption if I had to switch.

 

[MisterSandals]

How do most manage 2 or more banks in parallel if they have to switch from one to the other and there is an imbalance?

I dunno but handling that many potential amps is a good discourager. Big breaker comes to mind.

What is the rating of that switch? There are a lot of big wires, big fuses and everything going thru that little switch? Seems like a switch on each battery with half the current would be better. I dunno, just my $.02.

 

[pvgirl]

With only 2 strings in parallel fuses aren't required where the 2 solar circuits meet.

 

[Jracine]

I dunno but handling that many potential amps is a good discourager. Big breaker comes to mind.

What is the rating of that switch? There are a lot of big wires, big fuses and everything going thru that little switch? Seems like a switch on each battery with half the current would be better. I dunno, just my $.02.

Switch is rated for 500A continuous, 700A 5 mins and 1600A for 30 seconds @ 32VDC.

HD-Series Heavy Duty Selector Battery Switch - Blue Sea Systems

Up to 600 Amps continuous rating for large diesel engines.

www.bluesea.com

I have looked into breakers before and I have not found any that gave me a warm feeling so I went with a fuse/switch combo. You've brought up a good point though about if they were not at the same SoC. Perhaps I would be better off with breakers instead of the switch. I'll do some more research into it. Thank you!

 

[Jracine]

With only 2 strings in parallel fuses aren't required where the 2 solar circuits meet.

Thank you! I guess I was reading it incorrectly, the way I interpreted it I needed each string to have a fuse if the combined ISC of the array was more than the chosen panel's "max fuse rating".

 

[MisterSandals]

Switch is rated for 500A continuous, 700A 5 mins and 1600A for 30 seconds @ 32VDC.

Thats a nice switch!
I am afraid to see how much the >48V model costs...