Confused: i have 48 volt lifepo4 230ah diy battery. Can i get a 230ah 16s BMS

[SheilaInTimmins-ON-CAN]

I am confused about getting a BMS for the above battery. I don't see any 230ah BMSs. I cant even find 200 ones for sale. MUST I get one, given I have an all in one (POWMr 5k LVM 48volt mppt hybrid 120 volt only) -will this not allow me to set cut-offs. I do have 2 8S cell monitors I can attach to monitor individual cells. I desperately need electricity - been offgrid for 2 months with only a generator and broken down 12 volt lead acid system.
ALSO the screws on the all in one where I am supposed to attache the battery leads are minuscule! I have M12 size lugs and 2-ought cable -is there some way to make the inverter screws bigger (like one would make a plumbing pipe go from quarter inch to half inch with an adaptor piece. Sorry typos donèt know how to use this laptop. Any help would be greatly appreciated.
ALSO I have taken apart my old mobility scooters and scavenged and found small inline fuse- and some 50amp button circuit breakers-greater than my 8amp solar input-that I could use on solar string series 9x230 watts -and bought an amp wiring kit with 120 amp atc fuse - can I put this between the inverter and battery for now and I will buy a T1 shortly
I also found an old 60 am 220 volt DC breaker box siemans se222 - can I or should I use this somewhere for additional safety. there is already a fuse box in the cabin I just bought in way north ontario near timmins - so presumably the loads are protected from this already installed fuse box...I've read the book and watched 1000 videos but started from knowing nothing at all about anything technical and cant seem to find the answers to my questions...

 

[SheilaInTimmins-ON-CAN]

I am confused about getting a BMS for the above battery. I don't see any 230ah BMSs. I cant even find 200 ones for sale. MUST I get one, given I have an all in one (POWMr 5k LVM 48volt mppt hybrid 120 volt only) -will this not allow me to set cut-offs. I do have 2 8S cell monitors I can attach to monitor individual cells. I desperately need electricity - been offgrid for 2 months with only a generator and broken down 12 volt lead acid system.
ALSO the screws on the all in one where I am supposed to attache the battery leads are minuscule! I have M12 size lugs and 2-ought cable -is there some way to make the inverter screws bigger (like one would make a plumbing pipe go from quarter inch to half inch with an adaptor piece. Sorry typos donèt know how to use this laptop. Any help would be greatly appreciated.
ALSO I have taken apart my old mobility scooters and scavenged and found small inline fuse- and some 50amp button circuit breakers-greater than my 8amp solar input-that I could use on solar string series 9x230 watts -and bought an amp wiring kit with 120 amp atc fuse - can I put this between the inverter and battery for now and I will buy a T1 shortly
I also found an old 60 am 220 volt DC breaker box siemans se222 - can I or should I use this somewhere for additional safety. there is already a fuse box in the cabin I just bought in way north ontario near timmins - so presumably the loads are protected from this already installed fuse box...I've read the book and watched 1000 videos but started from knowing nothing at all about anything technical and cant seem to find the answers to my questions...

sorry the breaker box is an ac breaker box - but i want to use it as a dc one I think.....É wish I knew how to make a question mark...

 

[Wibla]

There's no need for a "230Ah" BMS for a 230Ah battery. Your BMS needs to be rated for at least the power draw you are expecting.

5 kW at 48V is 104A. Get a decent 200A BMS.

You can use 2AWG cable between the battery and the inverter as long as the run is relatively short (<10 ft). I assume your old (larger) cable is surplus from the 12V system?

You'll also need a class T fuse close to the battery, rated for 150 or 200A.

 

[science-raven]

Yes agreed with Wibla, BMS rating is the peak sustained output of the BMS. It's best to have a BMS about 2x times higher than the peak amps of your system, for coolness and efficiency.

 

[DJSmiley]

Capacity != current.

You can have a huge bank, but the BMS should only be able to hande the current you're going to use. Just like a fuel tank: A 40 gallon tank doesn't require a 40 gallon/min pump...

I would oversize the BMS by at least 30-40% in relation to the expected peak output, so it's generating less heat tho.


And yes, you can have a 400Ah bank with only a 20A BMS, as long as you're not pulling over 20A you're good.

 

[SheilaInTimmins-ON-CAN]

There's no need for a "230Ah" BMS for a 230Ah battery. Your BMS needs to be rated for at least the power
5 kW at 48V is 104A. Get a decent 200A BMS.

You can use 2AWG cable between the battery and the inverter as long as the run is relatively short (<10 ft). I assume your old (larger) cable is surplus from the 12V system?

You'll also need a class T fuse close to the battery, rated for 150 or 200A.

Thanks! My 2-ought is brand new, specifically for the run between the inverter and batteries - which will be about 18 inches or so. I would feel a lot better using the thick cable given the powerful batteries and being off-grid with no fire-station or even running water ...i just don't know how to attach the big cable given the posts are so tiny on the inverter...can I attach the 2 awg cable to the tiny posts and run it out a few inches and then attach it to the big cable or is that dumb...(question mark).i guess I could put the anl fuse in between the two different size wires just until I can source a \t2 fuse (question mark) I spent a week 5 hours south of here searching for solar equipment and couldn't get anything.and amazon won't deliver up here and can't get post box till omicron is over with....