LiPo 22.2V discharged to 8V. Help on discharge cut off!

ESK8 Electronics
1

Hey, so I unfortunately left my skateboard on for the night. I have 2x3s so 22.2v and i checked that they are now at 8.6v. I know that at this point it’s better to just throw them away, since it is dangerous to charge them and 1 cell is actually fully dead.

But now I need some help. Is there a way to have a device between the batteries, that cuts the power off, when the batteries come to the cut-off voltage. I have a 12v to 5v adapter also between the vesc and the batteries. Even if I switch the whole thing off, the batteries still discharge. I did a quick schematic as well.

Thanks in advance.

Untitled
Untitled1152×648 4.91 KB

2

What for you need that 12V adapter? Did you set cut of voltage in vesc? What kind of switch? Batteries obiviously shouldn’t drain themselves very fast if they aren’t connected anything.

3

I use the adapter for 5v led strip. As a switch is use a loop xt-90, so no power can go through there. Yes, cut off voltage is set

4

Do you mean that the batteries drained themselves after you had pulled out the XT-90? Cause according to your diagram, thats not possible…

5

no, i had the xt90 attached, but i want to know that is there a way to have another autoswitch that cuts the power out when the cells are too low. Like the lipo alarm but as a switch.

6

People use vesc and bms. I think that the fault is your batteries. You have over drained them multiple times or they are faulty in some other way. For example you shorted them in some point.

7

I actually have shorted them before, but the batteries were basically new, charge count was maybe 4 or 5.

Forgot to mention that the charger is always connected, it’s in the board. Maybe the charger is drawing power?

8

One short was enough to ruin my lipos. Not saying that shorts always ruin your batteries, but it might. What kind of charger?

9

Its the vesc that have drawn current. If you let the XT90 stay in, the vesc will get power, and the LED`s will light.

10

I use this charger rn, but I’m already replacing it with a proper bms:

https://hobbyking.com/en_us/turnigy-b6-compact-50w-5a-automatic-balance-charger-2-6s-lipoly.html

11

Yeah I know that, but the batteries still discharged even if the xt90 wasn’t connected.

12

Now I’m just confused, since first you said you had the XT90 switch connected.

And then 1 hour later you say this…

Was the XT90 switch connected or not?

13

lol

Basically, when the batteries went dead fast, the xt90 was connected. So i want something to cut off the power incase i forget the xt90 connected.

BUT another problem is that if the xt90 isn’t connected, the batteries still discharge but a lot slower. So I want to know that what draws power then.

I have two problems!!

14

just get a charge only bms for 20$ dude, its worth it

15

Any suggestions on what to choose?

16

Im not sure if you can fix these batteries somehow, but if you get new ones go with supower,bestech diebie but this one is a little expensive, bestech ones are great and small, and cost around 20

17

The device you are describing is called a BMS.

18

Maybe I can every time just remember to take the xt90 out. But do you think that the charger draws the power?

19

Can’t say for sure but it is possible. I would say that buy new batteries, bms and some charger

20

Is this one too sketchy to buy?

Can anyone hit me up with a link to a good and cheap bms that includes discharging at 50-60A as well?