I am looking to see whether is it possible to use a dual pole breaker between the MPPT output and Battery.
I am asking this question as I read that there were some issues with using dual pole isolators for inverters (Multiplus II) in parallel. Even though this issue seems to have been fixed in newer revisions of the inverter, I just want to make sure that these issues or other problems are not caused on the MPPT by using a dual pole breaker.
MPPT i am looking at: SmartSolar MPPT RS 450/100-Tr.
The issues you read about using DC breakers with inverters is usually because they are undersized or poor quality breakers.
What size are you planning on using? Can it take the minimum of 35mm² battery cable recommended? Is it a good quality one? Is it purely for disconnect or are you planning on using for overcurrent protection as well?
Thanks For the reply.
The double pole breaker will purely be for isolation, I will have separate fuses for protection, I have not decided on a breaker brand but I am considering the Schneider Acti9 DC range breakers.
The issue regarding the inverter dual pole isolation was that the comms connection was not galvanically isolated from the negative, See: https://community.victronenergy.com/questions/29736/vebus-isolation-quattro.html causing the circuit to be made through the ground of the comms. (this is how I understand it at least.)
Should this be something I worry about on the MPPT if I isolate both + & - ?
(I could also just be overthinking all of this)
Ah yes, you should not disconnect negatives between units, but you can after the bus bar down to the battery. It is the galvanic isolation problem. You understand correctly there.
For the mppt there is not the galvanic issue. Both poles can be broken. And no sometimes overthinking is good. Best not to make an expensive mistake.
If you are using CAN to connect it to the GX there is the terminator that takes care of things the communication is a totally different system.
Ah yes, you should not disconnect negatives between units, but you can after the bus bar down to the battery. It is the galvanic isolation problem. You understand correctly there.
For the mppt there is not the galvanic issue. Both poles can be broken. And no sometimes overthinking is good. Best not to make an expensive mistake.
If you are using CAN to connect it to the GX there is the terminator that takes care of things the communication is a totally different system.
