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Mrbf Terminal Fuse instead of Class T

If your MRBF fuses are 300A (described as 300A, diagramed as 400A?), they are pretty safe from ever getting more than the 150A that the BMS will allow. So nearly 2x oversize?
I suppose if the BMS failed in an always-on state, a 300A BRBF is possible to be of use.

And 200A breakers, presumably for switching?

Seems like an awful lot of mismatched fuses and breakers all over the place.
 
That 400 was a mistake, 300 amp terminal fuses. I was thinking they are catastrophic fuses... 200 yes for switching... Victron suggests 400 for that Inverter. That's a mega fuse.
 
I think the MRBF and the breakers are redundant, but not wrong. The redundancy does add a small amount of resistance.

The Multiplus 12/3000 is rated for 2400 watts continuous so that's a draw of about 200 amps (2400 w / 12.8 v / .94 inverter efficiency). My opinion is that you would be hard pressed to pull 400 amps even for a short surge. But, you're right that Victron calls for a 400 amp fuse to the inverter. I have the same inverter. I'm running twin 2/0 cables, each with a 200 amp fuse.

Your cables from the battery are oversized and that's OK. The breakers and fuses are also oversized. I would be more comfortable with a smaller MRBF amperage, maybe 200 amps. That would allow you to run on just two batteries and still satisfy the theoretical 400 amp max draw of the inverter (based on the fuse size recommended by Victron). The smaller amp fuse rating would allow it to blow quicker in a catastrophic situation.

It mostly comes down to how much load you plan to put on the system. I doubt that I'll ever see a 200 amp surge on mine and 125 amp continuous would be from the microwave and only for short periods.
 
I think the MRBF and the breakers are redundant, but not wrong. The redundancy does add a small amount of resistance.

The Multiplus 12/3000 is rated for 2400 watts continuous so that's a draw of about 200 amps (2400 w / 12.8 v / .94 inverter efficiency). My opinion is that you would be hard pressed to pull 400 amps even for a short surge. But, you're right that Victron calls for a 400 amp fuse to the inverter. I have the same inverter. I'm running twin 2/0 cables, each with a 200 amp fuse.

Your cables from the battery are oversized and that's OK. The breakers and fuses are also oversized. I would be more comfortable with a smaller MRBF amperage, maybe 200 amps. That would allow you to run on just two batteries and still satisfy the theoretical 400 amp max draw of the inverter (based on the fuse size recommended by Victron). The smaller amp fuse rating would allow it to blow quicker in a catastrophic situation.

It mostly comes down to how much load you plan to put on the system. I doubt that I'll ever see a 200 amp surge on mine and 125 amp continuous would be from the microwave and only for short periods.
Thank you, well I guess I'll have to return the 300amp Terminal fuses for 200.
 
I would go with 150a MRBF to match the BMS and skip the breaker. I expect each battery will provide 75 amps max. With 4/0 continuing to the inverter I would skip the 300a fuse unless there are additional and significant power sources to put the system over the 400 ampacity of the 4/0. The fewer crimps, lugs, connections the better IMO.
 
I would go with 150a MRBF to match the BMS and skip the breaker. I expect each battery will provide 75 amps max. With 4/0 continuing to the inverter I would skip the 300a fuse unless there are additional and significant power sources to put the system over the 400 ampacity of the 4/0. The fewer crimps, lugs, connections the better IMO.
Interesting thank you
 
I would go with 150a MRBF to match the BMS and skip the breaker. I expect each battery will provide 75 amps max. With 4/0 continuing to the inverter I would skip the 300a fuse unless there are additional and significant power sources to put the system over the 400 ampacity of the 4/0. The fewer crimps, lugs, connections the better IMO.

The JBD 120 amp BMS has been tested to perform above it's continuous rating. So a 200 amp fuse on a 150 amp JBD BMS isn't beyond the range of what the BMS can produce during a surge.
 
Where does the negative on the 12v breaker positive that is pictured circuit return to?
 
Where does the negative on the 12v breaker positive that is pictured circuit return to?
It goes from that lynx distributor to the 12v panel...It's already installed from my previous install ,and I just upgraded to 1/0 from the what the original was on the Camper... But I'm going to redo the drawing tonight.
 
What will be the nominal voltage of your new battery system once running?
 
What will be the nominal voltage of your new battery system once running?
Not sure I understand the question, but the 4 12v battery's will be paralleled and combined with the Victron Lynx Power IN. 12.8? The highest current would be max 2000 watts, but not often.
 
Was curious you noted the separate 12v circuit as being '12v' so that made me ask the question.
They seem to be in stock?
 
Was curious you noted the separate 12v circuit as being '12v' so that made me ask the question.
They seem to be in stock?
Thank you good find. And thank you for the help.
 
Could I replace those 4/0 battery cables that are oversized with 2/0? I think it works but I want to be sure.

If it's working, I wouldn't change it. An oversized cable isn't something to worry about (too much). A breaker or fuse that is oversized is a concern.
 
Since each battery has a 150 amp limit why not use 150 A MRBF fuses. The need for a breaker in each battery feed to the distributer seems unnecessary. MRBF are rated 10,000 amps interrupt at 14 volts so should be suitable.
 
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