Discounted SOK 12v, 100ah - bad BMS

[HighTechLab]

shouldn't be that difficult. They are all bolted cells so it would be easy enough.

 

[Bud Martin]

My battery just shows up today, 3-01-2023!

 

[sollap]

That was quick! They must have got it out the door right away on Monday. It had to be crazy busy for them with the move.
Do you plan on opening your battery and checking it out any time soon?

 

[Bud Martin]

The battery came in double boxed very well pack, it required Fedx signature for receiving.
The battery looks great, no scratches or anything.
I check the Voltage at the terminals with 10 Ohms load and it shows about 13V.
I took it apart, the bussbars that are attacked to the battery terminals are kind of short not much room to put a nut driver on them.
I up plug the BMS sensing cable and then check the Voltage again with load, it shows nothing, putting the BMS cable in and I get the Voltage back.
I am charging it up with 10A right now since noon, it starts at 50% SOC and now it is getting full.
So far I do not see anything wrong with the battery, the description says the BMS is brick so it will not allow the battery to charge or discharge.
I download the app and able to see the status of the cells, Voltage, etc.
I will run the capacity test when it is fully charged and will post some pictures.
I wish I bought two of them.

See video @3:01 about the bolts on the battery terminals.

 

[sollap]

Excellent. I'm glad your battery is doing so well. Watch that high cut-off, in case the BMS is still not right.
Thanks for the video. I'm looking forward to receiving mine, I even cleared a spot on my bench for them.

 

[Bud Martin]

The test is done! 102Ah 1280Wh!
Delta at full charge to 14.40V is 5mV, 50mV at the end of the test.

 

[timselectric]

The BMS works?
You should complain and request a refund.
You didn't receive what you expected, ordered, or paid for. lol

 

[HighTechLab]

That BMS may not be bad, but it is a v1 BMS and there have been quite a few revisions to it...some app functions may not work well, others at all, for example the status indicator details were added in later version, %soc reading is always wrong, and calc capacity changes randomly for who knows what reasons. Heaters can get stuck on draining battery to 0v...if you never plan to get it cold, and ignore the app, it's probably fine.

 

[timselectric]

Ok, that's better.
I was really concerned that people were getting a fully functional unit. And was worried that there might be rioting in the streets. lol

 

[Bud Martin]

I disconnect the heater connector since I do not need it, the SOC and the Ah are way off, I only care that the HVD and LVD are working and the cells are in really good condition.
BTW, how you can tell that it is V1 BMS?

 

[HighTechLab]

BTW, how you can tell that it is V1 BMS?

The spot where they added the revision numbers is totally blank.

 

[42OhmsPA]

Mine are scheduled to deliver tomorrow. Still hunting for JBD's that can be ran in series to 24v. Initially I was going to salvage the cells and make one pack but I realized I'd use the 12v packs elsewhere when I don't run the old 24v system.

 

[wiseacre]

Mine are scheduled to deliver tomorrow. Still hunting for JBD's that can be ran in series to 24v. Initially I was going to salvage the cells and make one pack but I realized I'd use the 12v packs elsewhere when I don't run the old 24v system.

It's implied that the 4s JBDs at Current Connected can be used in series for 24v
From CC's website:

If you had 8 cells, yet you still wanted to build a 12v pack, two options exist. The cells could be connected in parallel groups of two cells, then connected in series and managed by one single BMS, but the drawback to this is the loss of individual cell monitoring. The second option is to build two 12 volt battery packs, each with their own BMS – then connect the two packs in parallel.

Best to ask @HighTechLab to confirm

 

[HighTechLab]

It's implied that the 4s JBDs at Current Connected can be used in series for 24v
From CC's website:

Best to ask @HighTechLab to confirm

Yes but we're out of stock

 

[42OhmsPA]

Yes but we're out of stock

Thanks for confirming they will support it.
I'll keep an eye on stock.

 

[42OhmsPA]

Finally got around to pull one apart, FedEx is supposed to deliver the second one this week.
@HighTechLab @Bud Martin can you confirm I'm seeing this right, black is positive, brown is negative?
I'm ready to bring them back to life but don't want to kill them for good.
I plan to set to 2.75v @10a until current tapers, repeat at 3.35v and 3.64v; is that a terrible idea?

 

[Bud Martin]

Black terminal is Positive, Brown is Negative.

"I plan to set to 2.75v @10a until current tapers, repeat at 3.35v and 3.64v; is that a terrible idea?"
What Voltage do get on each cell? Why 2.75V?

 

[42OhmsPA]

Thank you for the insanely fast reply.
No reason in particular, where would you start at?

 

[42OhmsPA]

Black terminal is Positive, Brown is Negative.

"I plan to set to 2.75v @10a until current tapers, repeat at 3.35v and 3.64v; is that a terrible idea?"
What Voltage do get on each cell? Why 2.75V?

They were all ~0.20v
Climbing quick.

 

[Bud Martin]

Thank you for the insanely fast reply.
No reason in particular, where would you start at?

What is the Voltage on the cell right now?
If the cell is higher than 2.75V then setting at 2.75V charging Voltage then nothing will happen.
You can start at 3.3V.