JBD BMS - which one?

[MartinRaz]

Tried to get help from JBD - but no answers to my question.
Overkill is out of sale, so not an option.

I have this battery pack: https://www.aliexpress.com/item/1005001270537853.html?spm=a2g0s.imconversation.0.0.dde23e5f7H0GOQ

I was first looking at this: 4SLFP120A UARTRS485 - https://www.aliexpress.com/item/32858179124.html
But then found out they also sell this: 4S Lifepo4 200A - https://www.aliexpress.com/item/1005001271521083.html?spm=a2g0s.imconversation.0.0.dde23e5f7H0GOQ

I have 300W solar, and would like to be able to discharge up to 2000W - not actually certain I will, since it is for Campervan, and current appliances way smaller. But better to have possibility when building and then not use i think.
I get that the second option, going to 200A cost approx double, but that price difference is ok.

Also, if I need bluetooth, should that be bought seperate?
Where to find?

 

[HRTKD]

Discharging a full 2000 watts at 12v is 166 amps. So a single 120 amp BMS isn't going to cut it.

Options:
1. Put two BMS on the same battery pack. Not my first choice. Kind of a goofy setup. Not recommended for beginners.
2. Create two 4s batteries, each with a 4s 120 amp BMS. Expensive. Allows for redundancy. Relatively straight forward. 240 amps!
3. Find one of the higher tech BMS that uses a contactor instead of FETs. Much higher amps. Not recommended for beginners.

I went with option 2 and it's working well for my RV.

Due to overwhelming popularity, Overkill Solar is busier than a one armed paper hanger. You can certainly send them an email asking for advice. The worst that will happen is that they ignore you. I went with Overkill Solar for the customer service and they're located in the U.S.

 

[MartinRaz]

But since Overkill is sold out, I was looking at Ali.
Is this suitable? https://www.aliexpress.com/item/1005001271521083.html?spm=a2g0s.imconversation.0.0.dde23e5f7H0GOQ

 

[HRTKD]

But since Overkill is sold out, I was looking at Ali.
Is this suitable? https://www.aliexpress.com/item/1005001271521083.html?spm=a2g0s.imconversation.0.0.dde23e5f7H0GOQ

I don't know which item that link refers to.

 

[MartinRaz]

Header says:

3S 12.6V 4S 16.8V or 4S 14.6V Lifepo4 Battery BMS with 120A to 200A constant discharge current for 12V Converter power UPS​

And model is the

4S Lifepo4 200A

And my battery pack is 4x3,2V - so would assume it works out right.

 

[HRTKD]

There have been a couple of posts with problems with the higher amp versions. The 120 amp version seems to be solid.

 

[MartinRaz]

There have been a couple of posts with problems with the higher amp versions. The 120 amp version seems to be solid.

OK - I will stick whit that then

And that would then be this?

49.21US $ 5% OFF|4s Or 3s Li Ion Battery Smart Bms Or 4s Lifepo4 Bms With 60a To 120a Constant Current And Uart Or Rs485 Communication - Integrated Circuits - AliExpress

Smarter Shopping, Better Living! Aliexpress.com

www.aliexpress.com

Model: 4SLFP120A UARTRS485

 

[HRTKD]

That looks like it. I like the Overkill Solar version because I can specify the number of cables as well as the size of the cables.

 

[MartinRaz]

Yeah, would also have bought the Overkill had it been in stock!
Thank you for your help and guidance!

 

[HRTKD]

I would have at least asked Overkill what their expected re-inventory date was.

I've been throwing around the idea of getting two of their newer BMS, just so I can get the fancy bolt-on connections.