Yes, in the industry we call those "Spicy Pillows". Handle with care! The mechanical stress can cause separator failure and if the cell still has a high charge, it can go into thermal runaway. Yeah, If you are going to replace cells, it's always a good idea to discharge them before taking the compression off.
On Thu, Aug 6, 2026 at 3:57 PM Mr. Sharkey via EV <[email protected]> wrote: > Last time I bothered the list about this, replies from Cor, Jay and > -Phil- who all chimed in to say that it's not necessary to discharge > Leaf modules before removing the compression, just don't charge them > without recompressing. > > Today, finally, I'm getting around to replacing the two > half-defective modules in the 2P5S Leaf pack in my ElecTrak tractor. > After removing the pack intact from the front battery bay, I put it > on the bench and began loosening the 5/16" threaded rods that provide > the compression. I reached the end of the threads on the rods, and > there was still excessive compression, and a 3/8" gap had opened > between the two defective modules, exposing the threaded rod at the > top of the modules, which are side-by side in the pack. It appears > that the defective modules have swollen appreciably, while the > remaining healthy modules in the pack maintained their positions and > don't seem to be excessively puffy. > > So, question: Is this normal and expected for defective modules? I > have a feeling that one of the two bad modules had dendrites, as it > would slowly lose charge while in storage with no other load > connected. It would drag it's buddy-pair module to the same lower > voltage, as each half-module is parallel connected to it's mate > before being connected in series with the rest of the pack. > > I've begun discharging both of the defective modules completely, > draining the charge with connected 12 volt, 50 and 100 watt > incandescent lamps. I was going to do this anyway before sending them > off to the recycle facility at our local town dump, but as a > precaution, decided I'd drain them completely before releasing the > remainder of the compression. > > Other then having a big steel bucket of water handy, would anyone > like to offer suggestions on what I should expect once the bar clamps > come off? I've clamped the pack such that I can remove the nuts from > the threaded rods without blowing a hole in my garage wall. No sure > how much expansion to expect or how many changes of clamps I'll need > to reach full release. > > _______________________________________________ > Address messages to [email protected] > No other addresses in TO and CC fields > HELP: http://www.evdl.org/help/ > OT: If you use an Android device, please read https://keepandroidopen.org/ >
_______________________________________________ Address messages to [email protected] No other addresses in TO and CC fields HELP: http://www.evdl.org/help/ OT: If you use an Android device, please read https://keepandroidopen.org/
