Uh. Oh. What did I do to my Lipos???

[KellyC]

I have three Reedy Wolfpack lipos
They are 25c 7.4v 3000mAh.

I've been using them regularly over the last two years with my and my kids SCX10s.

I always balance change the batteries and rarely store them for more than a couple weeks either fully charged or charged with the storage mode setting on my charger.

This weekend, I recently broke the batteries out to run after what was probably their longest stretch of non-use, likely 4 to 5 weeks. It's likely between the three of them, one put away fully charged and the other two partially after the last time I used them.

When I went to balance charge them this weekend, all three of them stayed on the charger well over 100 minutes and "timed out", triggering auto shut off on my charger.

With one of them I tried to discharge to see if that would work, but the charger declined it saying "incorrect voltage."

I've run dozens upon dozens of cycles on these batteries over the last couple of years, and although I've always balance charged them, I haven't been that great about putting them away in storage mode and some of the gaps between use recently have gone pretty long. So I get it if I've toasted one battery, but, what I can't figure out is it possible that all three are toast at the same time? Or am I missing something with the charging process?

I should note that after getting "timed out" during balance charging, I'll test run the batteries in our rigs and only get around 20 to 30 minutes run time which is very low compared to what we're used to. I also cooked an older AE3 ESC in my SCX10 this weekend, causing it to smoke. I initially chalked it up to being an old ESC with a ton of cycles on it, but I wonder if it's related to the batteries...

 

[tweeter79]

Run one of your lipos until your LVC kicks in, then try a charge cycle without balancing it. Check to see if that gives you a longer runtime.
If that doesn't change anything, try another charger. Or try cleaning all your balancing leads/plugs to see if that helps anything.

 

[WHITE-TRASH]

Sounds like a cell or 3 was allowed to discharge too far while in storage. I've charged a couple packs on nihm mode for a minute or so to bring the voltage up to a level that they could be properly charged at in lipo mode. I'm sure someone will point out that I'm going to die in a lipo fueled fire some day. Ill take my chances. :lol:

 

[CM9000]

go buy a lipo safe bag and do what white trash says. it works. ive saved 3 batteries last month this way.

 

[emilsolbat]

It could also be that the charger is defective. A faulty charger would explain why all three of your batteries suddenly started acting up.

 

[CM9000]

It could also be that the charger is defective. A faulty charger would explain why all three of your batteries suddenly started acting up.

I wouldn't exactly say that... most chargers wont bring a lipo back above the lvc cutoff as a safety precaution. one cell could be just below and the charger will no longer charge it.

as I stated above, do what white trash said before you buy a new charger.

"thumbsup"

 

[mikemcE]

What is the cell voltage ?? If too low check your LVC

 

[msf1t-]

What is the cell voltage ?? If too low check your LVC

Sorry to hijack, I have two lipo's that have puffed enough to open the hard cases they're in. Cells in both batteries are all reading above 3.5V.

What causes them to puff?

 

[ADlBOO]

Sorry to hijack, I have two lipo's that have puffed enough to open the hard cases they're in. Cells in both batteries are all reading above 3.5V.

What causes them to puff?

Over charging and over heating. You should probably stop using them if they've already been damaged.

 

[durok]

Discharging too much is a major contributor as well. Battery manufacturers tend to state this is the worst of all.

 

[KellyC]

Sounds like a cell or 3 was allowed to discharge too far while in storage. I've charged a couple packs on nihm mode for a minute or so to bring the voltage up to a level that they could be properly charged at in lipo mode. I'm sure someone will point out that I'm going to die in a lipo fueled fire some day. Ill take my chances. :lol:

Ok. i will try this. So my objective is to just put the pack on the charger in nihm mode for a minute or so? Am I watching for anything on the charger or purely going off of time?

And then what? Switch back over to Lipo balance mode?


Thanks all for the suggestions.

 

[WHITE-TRASH]

If your charger has a voltage readout let it go until it shows over 3.2 volts per cell or so. Once it has that surface charge lipo mode will work.

 

[KellyC]

Ok. Here's an update.

I established that all three of my lipos will not take a "Balance Charge" with my charger. As many pointed out, this is suspect, but I was leaning towards the fact that I've recently haven't treated them that great, vs., issues with the charger.

I "quick charged" two of the batteries and due to time was able to test one which ran for around 30 minutes before I had to go do something else. Battery seems like it has plenty of "go" left.

I ended up ordering an identical battery off of Amazon because it was cheap and we can always need another lipo. My charger, a Hitec X1 would not balance charge the battery. I'm getting the same results with the new battery which are either the charger stops the process saying something like "Invalid..." or it just goes into balance mode but nothing is happening. That leads me to suspect that there is an issue with the balance board... correct?

I unplugged the balance board, no visible issues, although it does have sort of a burnt ozonish smell.

I assume a next step is to order a replacement balance board for $15 and rule that out?

Thanks for all the help. Everyone has been great. Much appreciated.

 

[JohnRobHolmes]

take the balance board apart or peel off whatever insulator is on it, see if you can spot damaged traces. Or just buy a new one. Probably a burned trace or dirty connection.

 

[KellyC]

take the balance board apart or peel off whatever insulator is on it, see if you can spot damaged traces. Or just buy a new one. Probably a burned trace or dirty connection.

Yep. That was it. "thumbsup"

I took it apart and the 2s circuit had burn marks and was disrupted. I ordered a new balance board, it got here yesterday, plugged it in and am balance charging batteries no probs.