Need HELP! 8S BMS, only 7 balance wires?! How do I connect?! Pictures included

[besugosolar]

So my BMS clearly states 8S (JBD\Jiaibada BMS), my batteries (B Grade) arrived today, luckily no damage (ordered from European Store NKON) and they all measure 3,26V, seem pretty balanced

But I can't connect the BMS to put my system to use, I only have 7 wires! I crimped the rings, only to notice... They were only 7 instead of 9. Is it even possible to wire this with only 7 or do I need to RMA the BMS?

That would suck, I have no energy anymore, my acid batteries barely hold 10\20W anymore and the shipping would take 2 weeks

Check pics and help if you can!

Thanks (Also I know I am aware I need to solder B- and C-)


Thanks!

 

[timselectric]

Did it not come with instructions?
If it is truly an 8s unit. And only provides 7 balance wires. I would guess that it's using the B- as double duty. But, this is just a guess. As I have no experience with JBD.

 

[besugosolar]

Did it not come with instructions?
If it is truly an 8s unit. And only provides 7 balance wires. I would guess that it's using the B- as double duty. But, this is just a guess. As I have no experience with JBD.

No instructions at all

 

[littleharbor2]

You might try ordering from OverkillSolar while waiting for a refund on the 7 wire bms. Chances you'll be able to get it faster.

8 Cell BMS (24 Volt) – Overkill Solar

overkillsolar.com

 

[besugosolar]

You might try ordering from OverkillSolar while waiting for a refund on the 7 wire bms.

8 Cell BMS (24 Volt) – Overkill Solar

overkillsolar.com

Too expensivel, I'm outside US as well... This one cost me 45USD... I dont get, it clearly says 8S, it has 7 pins for the cables and comes with 7 cables... Surely they should be knowing what they are doing... Probably mislabeled... So you think there is no way to get it working with 7 cables? For all I know 8S requires 9 balance cables, and surely I tried connecting these, 2 cables were missing...

 

[timselectric]

Definitely weird.
I'm not having any luck with Google, either.

 

[timselectric]

I would expect to see 9 wires, minimum.
This seems to be a mislabeled 6s.
But again, I'm just guessing.

 

[timselectric]

The sticker even appears to have been tampered with.

 

[Northernchateau]

I found the 2 links below and see that unit does come in 6S and up configurations.

https://www.currentconnected.com/wp-content/uploads/2021/07/DIAGRAM.png

JBD Smart BMS 4~22S 8S 17S 20S 21S 100A Li-ion Lithium Battery PCB for Freeshipping - Jiabaida BMS

Jiabaida BMS JBD Smart BMS 4~22S 8S 17S 20S 21S 100A Li-ion Lithium Battery PCB With Uart Rs485. High quality better service and favorable price with free shipping. Battery Management System for NMC/Li-ion Lifepo4 battery

jiabaidabms.com

 

[besugosolar]

It would need 9 wires, I see. Mislabeled I guess, it sucks. Damn it

 

[besugosolar]

These are my batteries, they look fine, all hooked up, 26,0V... All fine, except that damn BMS... Now I have no battery at home, for bad luck my previous batteries are now completely gone and so I can't use they anymore, while another BMS ships I'll have no electricity

 

[besugosolar]

These are my previous acid batteries (last 3 months at 30% DoD and started spitting acid all over... Never have they ever been overcharged... If you check "BateriasWeb" reviews on Trustpilot you'll see they are a scammy battery seller... Damn it

 

[timselectric]

Is that battery your only source of power?
Or just the preferred source.

 

[besugosolar]

Is that battery your only source of power?
Or just the preferred source.

Right now only source! After sun sets I have 0 power for 2 weeks now, I'm trying to get rid of this as fast as possible, and so I bought these LifePo4. They will be enough for my usage, I don't use more than 1kWh\24h... But can't use them now thanks to the wrong BMS they sent me...

 

[timselectric]

In a pinch, you can be the BMS.
If you have the time to do it.

 

[TomC4306]

Too expensivel, I'm outside US as well... This one cost me 45USD.

Clearly, the cheap one is going to cost more.
You got what you paid for.

 

[TomC4306]

If this were me...
Get a new bms on order. Quickest.
Connect up the new battery without a bms.
Set all chargers (mppt, utility) to 26.8 (3.35)
Carefully watch cell voltages on the first full charge to ensure none go dramatically high.

Hopefully you own a power supply that can charge at cell voltage....

When the bms arrives but before doing anything with it, charge the batttery to 26.8, disassemble the battery, connect the cells in parallel, connect your power supply and top balance charge tp 3.6.
Tear down and reassemble 8S WITH the new bms.
Reset chargers to 28v (3.5).
Good luck.

 

[timselectric]

Best option would be to get a Jk BMS with active balancing. Then you can just hook it up and go.

 

[TomC4306]

^that

 

[Mof]

Old thread I know, but I figured it out for the benefit of anyone else who buys one of these.

I also assumed it is a mislabeled 6S BMS. The 7-pin HY2.0 port is soldered into BC0-BC6. However, there is an additional 2-pin HY2.0 cable that comes in the package. Also there is a corresponding 2 pin port on the BMS soldered into BC21 and BC22. ( I see from the picture that OP has this port)

The 7 lead cable connects to BC0-BC6 as would be expected. The additional 2 conductor cable connect Cell7+ to BC21 and Cell 8+ to BC22 of the BMS. Voila. Works as expected.


Photo of underside of BMS where additional 2-pin port is soldered.


Photo of 2 connectors plugged into BMS.


Photo of Overkill App recognizing all 8 cells.