BMS advise

[gray webber]

Hi all!
I have settled on two 8s 280ah banks for my camp if I can built a good battery in house. My plan needs a good BMS for each pack.
Would like to find one that can handle up to 200amps charging and discharging. Needs over voltage, high temp shut down and if possible low temp shut down.
Would like recommendations and supplier sources if ok?
Thanks!

 

[TorC]

MOSFET based is most common and most power efficient. JK (AKA Heltec/etc.) and JBD (Jiabaida/Overkill/etc.) are well regarded and have 200A versions. Many people use Daly and it works, but it seems to have more problems. I'm about to get a couple JK ones for my 16S2P with 280Ah cells.

 

[gray webber]

MOSFET based is most common and most power efficient. JK (AKA Heltec/etc.) and JBD (Jiabaida/Overkill/etc.) are well regarded and have 200A versions. Many people use Daly and it works, but it seems to have more problems. I'm about to get a couple JK ones for my 16S2P with 280Ah cells.

Any supplier recommendation or will a google turn these up?
Thank you sir!

 

[TorC]

This is one that has been mentioned as reliable on the forum: https://www.aliexpress.com/store/gr....store_pc_home.pcShopHead_6000463681367.1_1_0

A search on the forum here mentioning the OEM family will turn up a few options.

 

[gray webber]

Does anyone know if vendor 18650battery store is a reliable supplier? Some over sea vendors are cons.

 

[Rossman]

You could get the JBD 7s - 20s 200A BMS from Docan, they are a popular vendor here, and that seems to be a relatively popular BMS.

 

[gray webber]

MOSFET based is most common and most power efficient. JK (AKA Heltec/etc.) and JBD (Jiabaida/Overkill/etc.) are well regarded and have 200A versions. Many people use Daly and it works, but it seems to have more problems. I'm about to get a couple JK ones for my 16S2P with 280Ah cells.

Hello Rodman! I built my 8s 280ah pack with the JK 8s20p unit. All working good but now I hear that if I want to double my battery with a second 8s pack, the JK BMS does not support 2p packs???? If so is there a good unit or answer to this?

 

[gray webber]

You could get the JBD 7s - 20s 200A BMS from Docan, they are a popular vendor here, and that seems to be a relatively popular BMS.

Is the JBD an active balancer? I’m running a JK now but may need to change to go to 2p packs for more power.

 

[740GLE]

JBD is passive, burning off excessive charge via heat at a very small rate.

JK seems we’re it’s at.

 

[gray webber]

So it throws away power. Maybe not bad but seams to fight against what a battery is for?

 

[gray webber]

So it throws away power. Maybe not bad but seams to fight against what a battery is for?

I’m in favor of active balance and keep the power. JK if I could use it in parallel banks.

 

[gray webber]

JBD is passive, burning off excessive charge via heat at a very small rate.

JK seems we’re it’s at.

Will the JBD support multi packs in parallel?
My other option would be to create a 2p8s pack and control with one Jk if that would work?

 

[gray webber]

JBD is passive, burning off excessive charge via heat at a very small rate.

JK seems we’re it’s at.

Could my idea of doing a 2p8s pack and use one JK work?

 

[740GLE]

I plan on running a 200A JBD in a 2P4S configuration. I can’t imagine why a BMS could care if cells are paralleled up.

But I would have gone with a JK if I did my homework before buying.

 

[gray webber]

Sounds like an answer. Less cost, smaller overall size. I also tested the low temp shut off after setting it to 1C. It worked! I need that for my seasonal camp. The battery is in a sealed heated box and the low temp shut down is the insurance.

 

[TorC]

@740GLE They don't, other than the BMS limits total power draw, whereas separate strings, each with a BMS, in parallel allows more draw. Add 1/2-2/3 ampere rating per additional string to provide plenty of headroom in case of uneven current flow from the batteries. Some claim limits on how many can be paralleled this way, but I suspect that has more to do with how much power is potentially available in a short than any genuine software or hardware limitation.

 

[hwse]

Hello Rodman! I built my 8s 280ah pack with the JK 8s20p unit. All working good but now I hear that if I want to double my battery with a second 8s pack, the JK BMS does not support 2p packs???? If so is there a good unit or answer to this?

I was the one who started the thread on paralleling the JK BMS and after a lot of hashing around we found that the concern was on reconnecting the paralleled battery banks when they were at significantly different SOC. That can and should be overcome by adding a fast-acting fuse to each bank that is rated for the max current of the BMS less. This is good practice anyway so it is not a big deal. They have now changed the documentation on the Hankzor web site to reflect this.
I am using the 4S JK on order and am using it in my build.

 

[gray webber]

If I’m reading this right: building a 2px8s cell bank and installing a single JK to it should provide the AH desired within the BMS limits?

 

[gray webber]

I was the one who started the thread on paralleling the JK BMS and after a lot of hashing around we found that the concern was on reconnecting the paralleled battery banks when they were at significantly different SOC. That can and should be overcome by adding a fast-acting fuse to each bank that is rated for the max current of the BMS less. This is good practice anyway so it is not a big deal. They have now changed the documentation on the Hankzor web site to reflect this.
I am using the 4S JK on order and am using it in my build.

So now the JK can be used in parallel banks if 1. A fuse or breaker is used to protect the BMS from imbalanced SOC.
2. The batteries that will be paralleled are charged to the same level before connection.
Either of these would limit an out of balance surge that could damage the BMS.
Do I have this right?

 

[hwse]

This bank will have 560A @ 12v nominal. The JK is limited to 200A continuous output which is significantly more than I need on my sailboat so 2p4s with one 200A BMS is plenty.
I will also be building a bank for my all-electric motorhome which has significantly higher demands. On that build I will build (3) 3s batteries, each with a 200A JK BMS which will be each connected in parallel to the charge buss with 200A fast-acting Class-T fuse so that I will have 600A output available.
There had been some concern from Hankzor about paralleling batteries but that was due to the possibility of the in-rush current when connecting batteries with significantly different SOC. The fast-acting fuse eliminates that problem.