4 x 12V 100aH batteries parallel … Where to fuse?

[Kh128]

Hey guys - hoping for a dorect confirmation here.

I’ve got a 3kw Renogy inverter that will run off 4 x 12V 100aH Renogy lithium iron phosphate batts hooked parallel.
Now I understand that the whole bank needs to be fused as well as the inverter. Planning on 350A ANL fuses.

My question is :
For each parallel connection on the batteries; is it okay to use Mrbf 100A terminal fuse ?
And is a BMS absolutely necessary ??
Rover charge controller has some battery info display so I think may be ok without a Bms ?
Thanks in advance!

 

[Texas-Mark]

For each parallel connection on the batteries; is it okay to use Mrbf 100A terminal fuse ?

That's what I do.

And is a BMS absolutely necessary ??

Yes!!!

 

[Kh128]

That's what I do.



Yes!!!

Thank you. One BMS for the 4 okay?

 

[Rednecktek]

Thank you. One BMS for the 4 okay?

The BMS is for balancing and safety of each battery, so each battery will have its own BMS. You might be thinking of a balancer to keep all 4 batteries evenly performing, but in a Parallel configuration this takes care of itself for the most part. Balancers are really only needed if you're connecting 12v batteries in Series to get a 48v bank OR if you're not going to be taking each battery to a common bus bar with equal length cables.

 

[Kh128]

The BMS is for balancing and safety of each battery, so each battery will have its own BMS. You might be thinking of a balancer to keep all 4 batteries evenly performing, but in a Parallel configuration this takes care of itself for the most part. Balancers are really only needed if you're connecting 12v batteries in Series to get a 48v bank OR if you're not going to be taking each battery to a common bus bar with equal length cables.

Ok it seems mostly unnecessary for each battery then? if batteries will be hooked parallel with equal length cables between them and 100mrbf fuses at each pos terminal. And a 350ANL going out.

 

[wpns]

Ok it seems mostly unnecessary for each battery then? if batteries will be hooked parallel with equal length cables between them and 100mrbf fuses at each pos terminal. And a 350ANL going out.

Each battery already includes a BMS, so no need for more BMS unless you are putting the batteries in series to make 48V, then you need an inter-battery BMS/Balancer/Equalizer.

Sounds like you have a good plan.

 

[Kh128]

Each battery already includes a BMS, so no need for more BMS unless you are putting the batteries in series to make 48V, then you need an inter-battery BMS/Balancer/Equalizer.

Sounds like you have a good plan.

Thanks for helping I just want to clarify my understanding.. The battery has (internal Bms) is what you’re suggesting by each battery includes a BMS ? Sorry for redundant questions!

 

[wpns]

Thanks for helping I just want to clarify my understanding.. The battery has (internal Bms) is what you’re suggesting by each battery includes a BMS ? Sorry for redundant questions!

Yes.

When I said that each battery already includes a BMS, I meant that each battery already has a BMS built into it inside the case with the individual cells.

 

[Kh128]

Yes.

When I said that each battery already includes a BMS, I meant that each battery already has a BMS built into it inside the case with the individual cells.

Thanks for your patience breaking it down for me! Have a great day

 

[Ampster]

The only thing I would add is instead of an ANL fuse between the pack and the inverter, I would recommend a Class T fuse.

 

[jsmetalcraft]

The only thing I would add is instead of an ANL fuse between the pack and the inverter, I would recommend a Class T fuse.

Class T for the win, but there is a shortage of them I was reading and the price is crazy now.

I have 3- 280ah batteries in parallel. Each one has it's own BMS, and ANL fuse. Then the leads go to a 3 pole 250a breaker that is connected to the bus bar. The inverter has an ANL fuse off the buss bar.

 

[Rednecktek]

Class T for the win, but there is a shortage of them I was reading and the price is crazy now.

Yeah, took me a couple years to find mine finally, but DonRowe came through for me.

MRBF are also a viable option and more readily available and cheaper.