Can you explain why you would put the battery disconnect switch AFTER the common bus bar? I would think if using two battery banks, the off switch of each battery should be before the common bus? That way, you can turn off each battery individually for maint.I would build 2X 12V/280AH battery packs, each with a BMS & Fuse. Set then in Parallel to get 12V/560AH and to have them share the Load/Charge which reduces "pack stress" and also provides a bit of fault tolerance.
To do this I always suggest that you build each battery pack as if it is the only battery in the battery bank, so it can handle the full Charge/Discharge capacity of the system because One Pack may disconnect for any number of reasons leaving only one pack standing.
The problem is getting a 4S BMS with enough capacity to handle that kind of amperage "safely". Rating Labels leave much to be desired, especially with FET based BMS'. Sadly the Overkill BMS only goes to 120A. I cannot recommend a 12V/300A BMS, I'm a 24V guy using Contactor Based BMS' which are more costly.
The wire gauge at 4.0 is GOOD especially for that distance. Do remember that it CANNOT be tight, it needs slack, also to bind the wires together to prevent/reduce EMF/RFI noise, which DC makes when separated. When it comes to this kind of Key Wiring I can only suggest high end stuff like Royal Excelene Welding Cable by Southwire. It is more costly but one of the best wires that can be used for solar systems.
Remember: Battery Pack to Fuse, to Common DC Bus Bar, to Breaker, to Inverter/Charger.
How often will you be pushing 200amps? Most folks swap out the cables for something that matches their workload.I just received a 200A BMS, for a 24V battery, the cables attached are 2 AWG, I wonder if this is sufficient? I was thinking of using larger cable for the rest, but are these short cables fine for the BMS?
Not often, I will be using a Victron 24/3000 inverter, with a cont output of 3000W, but peak of 6000W. There will be an induction stove of 3500W, which will hardly ever reach that output, I think.How often will you be pushing 200amps? Most folks swap out the cables for something that matches their workload.
Those high thread count silicon cables can take a lot of abuse.Not often, I will be using a Victron 24/3000 inverter, with a cont output of 3000W, but peak of 6000W. There will be an induction stove of 3500W, which will hardly ever reach that output, I think.
3000W/24V would be 125A.
I'm just a bit surprised that a 250A (not 200, my mistake) BMS comes with 2 AWG cables.
Electric winches are evil. (our truck weighs 4500kg, not including the camper box)I ALWAYS overcable inverters and winches.
Wire is much cheaper than trouble.
No. Its a matter of using the correct cables and fuses based on your load. The fact that Chinese BMS makers use under sized cables for their rated loads is just something we need to deal with.