Anatomy of a dead Lipo

[jkflow]

I managed to over discharge a Lipo (1.5V per cell) and the internal resistance (IR) on the middle cell went from ~ 3mOhm to roughly 7x. (21mOhm) upon recharging.
Performance went into the dumpster right along with it. Naturally the higher resistance is a sign of internal damage and subsequently the voltage on this cell will drop faster under load. This is a 'cheap' Lipo but leaving the name out as it has nothing to do with my mistake. Simply forgot to connect the Lipo alarm during discharge.

I've never taken a Lipo apart to this level, but curiosity killed the cat, so to speak. I've discharged the Lipo and the main leads were wrapped together, i.e. shorted.
Don't do this under a charged condition

Lipo IR values, they should all be similar. How similar is debatable but 7x is way too far out of the wheelhouse.
Individual cells on the right, those are the 'S' or 1S each, this was a 3S.

Opened the silver barrier of damaged cell, Individual sheets separated by insulating material.

This is a 'good cell'

Note: In the bad section, some 'leaves' turned brittle and one fell apart.

 

[Exc3l]

Accident Discharge? I came back from a run in my 4s Granite and accidentally set the charger to Discharge instead of Storage. Caught it in less than 5 mins. Was discharging at 1amp instead of like 3.

 

[MAVERICK@2]

Good info man

Glad no one was injured in the service announcement

 

[jkflow]

I have a DIY discharger, a bunch of resistors, heat sink and fans. Will discharge at ~ 6A on my 3S which is nothing crazy but will drain it in ~ 45 min. I let it go for about 2h before I realized.
Oddly enough, the other 2 cells were perfectly ok.

 

[Diem Turner]

I have a DIY discharger, a bunch of resistors, heat sink and fans. Will discharge at ~ 6A on my 3S which is nothing crazy but will drain it in ~ 45 min. I let it go for about 2h before I realized.
Oddly enough, the other 2 cells were perfectly ok.

I have a DIY discharger as well consisting of a bunch of halogen bulbs. When discharging a pack I attach one of these to the balance lead and set an alarm for 3.75V to avoid these kinds of incidents. They're also handy for passively balancing packs when not on a charger. If you're anal retentive about your batteries, this can be a nice tool on your Batbelt®.

 

[fish]

So this happend.

I left a 2S Lipo plugged into a car for like 5 days, in my trunk. :-/

Went to charge it, balanced leads don't work.

Voltage is reading 1.6v.
Slighly buldging. Not warm or anything.

What do I do with it? How do I dispose of it?

 

[slick2500]

Accident Discharge? I came back from a run in my 4s Granite and accidentally set the charger to Discharge instead of Storage. Caught it in less than 5 mins. Was discharging at 1amp instead of like 3.

I did that the other day too. Strange.

So this happend.

I left a 2S Lipo plugged into a car for like 5 days, in my trunk. :-/

Went to charge it, balanced leads don't work.

Voltage is reading 1.6v.
Slighly buldging. Not warm or anything.

What do I do with it? How do I dispose of it?



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Plug any 12v automotive light bulb into the battery then place the battery in a grill or out in an open area away from anything flammable and let it sit until the battery is completely drained at 1.64v it should not take too long. After the battery is completely drained snip the leads off as close to the pack as possible wile still being able to attach them together.

Now as far as disposal I think I remember someone saying that Lowes does battery disposal. Your local hobby store should know where to go, mine actually will take dead batteries and dispose of them for you.

 

[jkflow]

Once you do the full drain, just dispose of them in normal garbage.
Lowes, Home Depot etc stopped taking these batteries several years back, but really depends on your state. Trash can works and there is no danger, just keep those leads twisted.

 

[sumguy75]

Batteries Plus will take old lipo batteries. I have a location about a mile from my apartment so dropping it there is faster and easier than doing a full discharge. They told me its supposed to be a $1 fee, but I've dropped off 2 batteries there and they told me don't worry about the fee both times. Don't know where all they are located but they have a bunch of them in the PNW.

 

[ZooKeeper]

Batteries Plus will take old lipo batteries. I have a location about a mile from my apartment so dropping it there is faster and easier than doing a full discharge. They told me its supposed to be a $1 fee, but I've dropped off 2 batteries there and they told me don't worry about the fee both times. Don't know where all they are located but they have a bunch of them in the PNW.

I do this same thing, Batteries plus is the way to go. I just stock up batteries I need to recycle. Once I need to go over to the store to buy something (usually UPS batteries), I'll bring my box of dead batteries and turn them in. My local store has never even mentioned a fee for recycling and I've never had a fee on my purchase receipt for recycling.