Battery Cell Votage Fluctuating

[Zombi]

Guys, anyone heard of this before...

When charging my 3S battery light night, one of the cells started fluctuating voltage during the balance mode, going from about 2v to 4.2. The other 2 cells were fine though.

I'm guessing it must either be the balance board or the connector on the battery, as surely voltage can't actually fluctuate like that?

Anyway have any experience with this at all?

Cheers

 

[Solitaire]

Yeah, my guess would be in the balance circuitry. Either at the board, the board extension, the plug(s) or an internal issue with the LiPo itself. Try some different LiPo's to determine which area it is. Also, give each wire in the balance circuit a little tug and see if there is a loose connection at one of the pins.

 

[micro racer]

I had this happen once at the hobby shop I work at. The guy said he had ran his truck in some salt water and then his battery wouldn't charge and his charger said "Low Voltage." We tried it on the shop charger and one cell had about 4 volts and the other had around 2, just like yours.

So, has this battery seen any water recently? If it hasn't, it is probably a bad connection like Solitaire posted.

 

[TacoCrawler]

I had this occur when charging my 3s
a coupla' times actually.

turned out to be a bad connection on the balance plug.
Not the battery plug nor it's wires...
but an aft. mkt. extension lead from the battery's plug to the charger.

I guess I tend to pull on the wires when disconnecting
the balance plug.
doing it that way, is likely what caused a break in the wire.

I was frustrated with it initially...
because the wires and connections at the balance plugs
looked fine.
It was intermittent at first...
and wiggling the wires would make connection
but eventually it failed altogether
and my charger would not balance charge it.

a closer inspection revealed the issue.

After repairing the damaged connection...
I put brush on electrical tape at the base of the plug
and on the wires leading into it.

Not sure if it's the best solution...
but so far I haven't fubar'd that balance plug/ext. again.

 

[Zombi]

Thanks for the replies so far guys!

So yes, it has seen water action, this very weekend. And after that trail is when i got the problem Does that mean the battery is a write-off then?

I've sent it back to the shop now and they'll do some tests on it and work out what to do next.

Looks like although the Yeti might be waterproof, you can't dunk it due to the battery. All seems rather pointless having a waterproof rig then huh.

 

[Zombi]

Turns out it's the balance board and the battery itself is fine. Damn crappy balanceboards need to be made a little more sturdy :x

 

[robertjpjr]

Fresh Water is VERY different than salt water.
LIPO Batteries are Waterproof by nature.
That being said, connections can rust or oxidize. Salt water increases this dramatically.
The salt also increases the chance of shorting electronics because of its conductivity.

If your electronics are waterproofed Fresh water is fine. Still check for rust periodically.
Salt water is the Devil :twisted: It ruins everything, very quickly.

 

[thehighroad]

My balance board that came with my eco-8 does this too. I have to massage the connector a bit until it's stable. I've also shaved the locators off the balance leads themselves and plugged them into the charger directly.

 

[Zombi]

Fresh Water is VERY different than salt water.
LIPO Batteries are Waterproof by nature.
That being said, connections can rust or oxidize. Salt water increases this dramatically.
The salt also increases the chance of shorting electronics because of its conductivity.

If your electronics are waterproofed Fresh water is fine. Still check for rust periodically.
Salt water is the Devil :twisted: It ruins everything, very quickly.

All noted, thanks for the tips!