So my battery drained down to 2.5 volts over the winter storage. I thought I left it on the charger, but somehow it did not stay charged and actually drained down.
So now I can’t charge it directly from the charging port on my board. I am able to charge it going directly to the XT battery connector but that only gets me to about 29 volts and my charger stops charging. My guess is it sees no current flow and the light turns green.
Anything I can do to try to salvage or save this battery?
Leaving it below 3V/cell over time, theres a great posibility of dendrites starting to form inside the cell.
At 2.5V the cell start to take permanent damage. Under 2.5V/cell the recommendation is to recycle and never use those cells again.
This particular info comes from a senior chemist in the specific field of lithium-ion batteries. (collegue of mine)
Shit happens but I’d def toss it if pack voltage was that low!
So I measured each cell at the BMS and found 4 of the 10 cells at 0 volts. The other 6 all have 4.6 volts. Looks like those cells are bad. Is there an easy way to replace the bad cells or anyone that does this?
A battery builder or tech that could perform that kind of repair well enough, and safely enough, isn’t likely going to want to perform it for a number of reasons.
The cells at 0v are gone, and need to be decommissioned. The cells at 4.6v are also now compromised, and need to be decommissioned.
Trying to charge the battery without the BMS was not the wisest idea, as bringing lithium ion cells to 4.6v is fairly dangerous.
At that point, the whole pack needs to be safely recycled. Not charged, and ABSOLUTELY not shipped.
Trying to ship that would be a hazard, and not a good idea.
Just condemn the entire battery. It’s not going to work.
This is a list of awesome and safe battery builders in our community, depending on your location any of them can build you a pack (likely with better cells, better performance, and better longevity)
It’s good to see somebody being receptive to the experts around here, you might be surprised by how many people will 1: ask for help with a dead battery 2: get told by experts that battery isn’t safe. 3: get combative and/or ignore said experts and decide that a house fire isn’t THAT bad, wash rinse repeat.
I wish you the best of luck, it also may be worth doing a bit of research on lithium ion batteries, depending on their handling lithium based batteries can be incredibly volatile and unsafe, any questions you have someone here is sure to know, just ask here before you do anything with a battery that you’re not fully and entirely confident in your ability to do and understanding of risks.
And if it wasn’t already clear,
GET THAT BATTERY OUT OF YOUR HOUSE AND AWAY FROM ANYTHING FLAMMABLE.
Here’s why:
(esk8 sized battery explosion)
(Approximately 5-10wh battery ~1/100 the size of a “normal” esk8 battery)
(Big esk8 battery)
(Not sure of pack size)
Edit: I don’t intend to fear monger at all, and I hope this doesn’t come off that way. I just think it’s important that everybody understands the risks we all take when using and handling lithium batteries.
