I need some design help.

[lotsofsparks]

Hi guys I'm having trouble designing my off grid solar system.

Issue 1# where do I put circuit breaker and isolators?
I have had 2 120A CBs tripping at only 70amps that have destroyed my solar charge controllers by disconnecting the battery While leaving my PVs connected.
Can I trust my BMS to protect the cables beween the MPPT and battery?
I have great concerns over unprotected low resistance batteries and cables.

Issue 2 I have 3 batteries (2 x 100AH and 1 x 280Ah lifeo4 12V) that aren't supposed to be connected in parallel or series with each over according to the manufacter's instructions.
should I get a 300A double pole triple throw switch or an interlocking relay system either one even exists to change between the batteries using 1 inverter on standby?
should I use an ATS switching between 3 inverters and a generator on standby an exept the power drain?

 

[altenergy21]

Hi guys I'm having trouble designing my off grid solar system.

Issue 1# where do I put circuit breaker and isolators?
I have had 2 120A CBs tripping at only 70amps that have destroyed my solar charge controllers by disconnecting the battery While leaving my PVs connected.
Can I trust my BMS to protect the cables beween the MPPT and battery?
I have great concerns over unprotected low resistance batteries and cables.

It shouldn't destroy your charger.
My batteries come with breakers for each battery but you can put a 120A breakers between batteries and charger.

Issue 2 I have 3 batteries (2 x 100AH and 1 x 280Ah lifeo4 12V) that aren't supposed to be connected in parallel or series with each over according to the manufacter's instructions.
should I get a 300A double pole triple throw switch or an interlocking relay system either one even exists to change between the batteries using 1 inverter on standby?
should I use an ATS switching between 3 inverters and a generator on standby an exept the power drain?

If they're the same voltage you can connect them in parallel.

This is why I recommend buying kits from Signature Solar. They're put together in straightforward ways. No need to use the brain much.

 

[lotsofsparks]

It shouldn't destroy your charger.
My batteries come with breakers for each battery but you can put a 120A breakers between batteries and charger.



If they're the same voltage you can connect them in parallel.

This is why I recommend buying kits from Signature Solar. They're put together in straightforward ways. No need to use the brain much.

MPPT instructions always say you must connect the battery first then the PVs or disconnect the PVs before the battery otherwise you will destroy the controller.
My batteries say that they don't recommend connecting them in parallel.