Help Needed: Flat Battery

ESK8 Electronics
1

Hello, guys. I built my board about 4 days ago and never had a chance to test its limit. Well, today I went to the central park and rode till my battery runs out of juice. I set the cutoff limit to 3.2 V. I got some pretty happy result. Seried three 3s1p 5000mah and it went 13.2 miles with a top speed of 24.2(I think it can go faster but I am not able handle speed above 24.) Got back home, trying to charge, the battery told me that I have a low voltage pack. I lowered the charging current to 1/10 of the C so 0.5A according to some tutorials. However, the charger is only able to detect 2S instead of 3S. What is the problem? Is the battery still good for use? Addition to that, another battery pack is fine. How come the motor did not draw current from each of them equally?

Thanks for your help.

2

Put charger on NiCD mode and charge for 40seconds to a minute until the voltage is high enough. Then go to Lipo mode and charge normally

3

Check he cells with a multimeter and report back

4

Unfortunately, my charger is LiPro Balance Charger, it can only charge in lipo mode, no other modes :frowning:

5

Another unfortunate that I do not have a multimeter:(

6

Ahhh well in this hobby it is a very important tool and I highly recommend one. They are a few bucks from a hardware store or maybe automotive shop

7

alright, I will pick them up tmr in my local hardware store. Thanks.

8

No worries

9

Get a bms they arent expensive

10

I’ve had this, in fact I still do, I need to fix it but basically one of your balance leads have come off of its connection inside your lipo pack, maybe desoldered or just plain broken… This is why it can only detect two cells.

You need to take your pack apart, use a multimeter to detect which wire has disconnected and solder it back on…

11

That is my plan. But do you think I should just throw these batteries to trash?

12

Wow, solder a lipo pack sounds like a fire hazard.

13

Lol, how do you think the balance wires were connected in the first place?

14

I will leave these things to the pro lol. Do you think I should throw them or sell them at a very low price?

15

Don’t throw them, someone could salvage them. Sell them with full disclosure if you don’t want to solder it yourself, as long as they’re not all puffed up…

Where are you based? What’s the spec of the batteries?

16

I got three 3s1p 5000mah. $32 each. I am planning to sell three for $40 and get three new ones.

17

Ahhh if you EU based I’d have had them off you :confused:

18

I got my batteries fixed.

So basically I charged it at 1A(for safety issues), although the charger only detected 2 cells, I still went ahead and charged at 3 cells. After the voltage climbed up to about 3.2 V per cell, the charger is able to detect it as a 3 cell battery pack. So if anyone have this same issue, please charge at a much lower rate and always charge your battery pack in a Lipo safe bag.

19

one of my battery can only charge up to 12.5V and the other 12.47. Am I able to connect them to serie or will this cause a fire?

20

It sounds like you have a bad cell if the voltage dropped below a detectable level. You may get lucky and it may be ok from now, but it sounds like you’d be better off towing that dodgey cell.

Putting them in series now though will be fine, it doesn’t matter about the voltage difference.