plund
New Member
Hello!
I'm trying to build a system that looks like this: PV -> SC -> Batteries -> Isolated DC/DC converters -> Non isolated DC/DC converters -> loads
Solar charger is rated to 48V 120A, and the plan is to use 2 in parallel for 240A.
Batteries will be 48v 240Ah+, mostly used as a buffer for sudden changes in the solar output to keep the load somewhat stable.
Isolated DC/DC to take 48v down to 12v. There will be some in parallel to be able to use the full power available.
Non isolated DC/DC to take it further down from 12v to 3v. Same here, will be run in parallel.
Load will be run at 3v 100A, purely resistive load, max 300w. Input power is max almost 12kW, so max parallel loads is 38.
The PV's will be mounted on a roof, the SC on a wall and the rest of the system in a big "cabinet".
So to my question:
I want the cabinet to be protected from ground faults. So as I see it I need to break the current between the SC and battery, and also between battery and DC/DC converter. Also, as the first DC/DC conversion is isolated, if I have a GFCI on the battery side, I suspect that one can't detect a ground fault on the other side of the converter, since that current doesnt flow back?
However, looking for GFCI's, I can't really find anything that can withstand 240A, or they cost way too much, $5000+.
Any ideas how I can build my system and have it safe against ground faults?
I'm trying to build a system that looks like this: PV -> SC -> Batteries -> Isolated DC/DC converters -> Non isolated DC/DC converters -> loads
Solar charger is rated to 48V 120A, and the plan is to use 2 in parallel for 240A.
Batteries will be 48v 240Ah+, mostly used as a buffer for sudden changes in the solar output to keep the load somewhat stable.
Isolated DC/DC to take 48v down to 12v. There will be some in parallel to be able to use the full power available.
Non isolated DC/DC to take it further down from 12v to 3v. Same here, will be run in parallel.
Load will be run at 3v 100A, purely resistive load, max 300w. Input power is max almost 12kW, so max parallel loads is 38.
The PV's will be mounted on a roof, the SC on a wall and the rest of the system in a big "cabinet".
So to my question:
I want the cabinet to be protected from ground faults. So as I see it I need to break the current between the SC and battery, and also between battery and DC/DC converter. Also, as the first DC/DC conversion is isolated, if I have a GFCI on the battery side, I suspect that one can't detect a ground fault on the other side of the converter, since that current doesnt flow back?
However, looking for GFCI's, I can't really find anything that can withstand 240A, or they cost way too much, $5000+.
Any ideas how I can build my system and have it safe against ground faults?
