Certified FOCBOX Suppliers | Get Focbox Unity

Liion Cells Reading 0.6v?


#1

So I tested my liion pack with a multimeter today, it’s a 10S pack, reading a voltage of 6V!? There may be a split in one of the wires or something somwhere, but when I measure the individual cells they read between 0.5-1.3v? I only tested a couple but this seems really dangerous! I have no idea how they got this far discharged considering I’m using a VESC, and the limits are set to 30v cutoff…?
Any ideas?
What about the pack? Is it totaled?


Carbon Stealth Bomber | Dual Hubs | Dual VESC | 10S3P 18650 | Freebord Bindings
#2

They’re gone if their individual voltage is that low. Internal resistance increases and there cell loses capacity…

I wouldn’t charge them again…

Did you short circuit or leave a load on without knowing?


#3

They have shorted before… this sucks, never even used the pack.


#4

Dang… Did you have a BMS on it?

One of my multimeter probes fell out of my hands as I was measuring individual cell voltage and it short circuited the pack but my BMS saved it somehow. Not a single volt down or loss of capacity.


#5

Nope, do now tho


#6

Unfortunately having one now doesn’t really help


#7

All right just got home, took a look at the batteries and measured him with the multimeter again, and I think I must’ve just overreacted way too quickly earlier because I must not have had proper contact with the pad, because now they read 3 V


#8


#9

Weird… Each one is fine now? Kinda odd that you got that reading for all the cells individually. Maybe you had flux or adhesive on your probes.


#10

Yeah I think my probes have been like coated with something, I think I might’ve used one of them to scratch something recently, and that may have left a coating on them :grimacing:… I had only measured like three or four cells originally


#11

Dude - that’s awesome! i was bummed for you when i thought your pack was dead. that’s some serious $ down the drain if it’s dead.

I might check each individual cell w/ your MM and just confirm none have any issue. Did you also wire your pack for balancing already? I don’t see any balance leads in the picture above your MM?

Fingers crossed and GL!


#12

I originally thought the issue with having to do with the battery, when the VESC and the LCD were not lighting up, But it happened to be that the XT 90 anti-spark blew up… As far as I believe. I just took a look at my XT90S, and it’s bulging and very hot


#13

Pic? Wonder if you have too long of a “loop” and smaller wire or resistance caused an issue?


#14

It’s actually not a loop key, just the connector on the battery… Is that not recommended?


#15

I’m going to switch it out to be an xt90s loop key and a regular xt90 battery connector


#16

the direct connect w/o it being a loop key is actually preferred.

sounds like a qc issue, or you didn’t fully seat it - so it was running through the resistor section of the connection?


#17

That’s what i do, simply so i don’t need a ton of the anti-spark connectors (one for ea battery) vs a single loop key for all batteries.


#18

I don’t think it was properly connected.


#19

Ahh so you use the anti-spark side as the actual key, and the female end in the board so you only one key? Interesting…


#20

Yep! I did a quick how-to. Remedial, but for your perusal:

Simple and works. Just don’t do a huge loop. Paracord works well if you need a handle…