OhmGrown
Member
- Joined
- Sep 13, 2018
- Messages
- 55
So I created a few "standard" sized packs of 100 paralleled cells in order to power a project of mine recently. I created four of them about two months ago and they've essentially been sitting, not connected to any loads or in parallel or series to each other since they were completed (I needed to create a tray, plexiglass cover and ensure they could fit in my enclosure in the time being hence the storage period).
They were all close to full at that time, hovering around 4.1V or so. Just tested them again and three of them are still above 4.0V, however one, of course, is now down to 3.2V. Obviously I have one or more bad cells in the pack (really disappointed in myself that I didn't weed them out during the cell harvesting and testing phase but I likely just mixed a handful up during one of those late nights testing or it possibly went bad on me since then).
So, my question is, now that I've got all these packs welded up with fuses and tabs soldered to busbars, essentially all completed with not so cheap terminals and materials, can anyone think of a way to locate the self discharging cell(s) in the pack of 100?
The only things I can think of, without having to undo the entire pack, is to maybe point a thermal camera at it and see if maybe one cell is hotter than all the others? But I'm also pretty dumb so I'm not sure that the cell would register a higher temp, even if I happened to have a nice FLIR camera (which I don't).
I suppose I could also undo the fuses on the positive end one by one, checking the current running to each cell with a multimeter then (I do have a DC clamp meter but no way in hell I'll get that clamp just around one fuse leg). I'd also rather not make a brand new pack of 100 but, honestly, that may be the quickest solution. I'm hoping against hope there's a better solution that's been mentioned on this board that I just can't seem to find, so if anyone knows of it, I would greatly appreciate it. I shall send you a 12 pack in the mail.
And sorry for a new thread for such a specific, selfish question, I tried searching for a like minded existing thread or post but came up with squat. Thanks for the help and time guys!
TLDR: Any ideas on how to find one cell in a pack of 100 that's self discharging/parasitic without taking apart the pack?
They were all close to full at that time, hovering around 4.1V or so. Just tested them again and three of them are still above 4.0V, however one, of course, is now down to 3.2V. Obviously I have one or more bad cells in the pack (really disappointed in myself that I didn't weed them out during the cell harvesting and testing phase but I likely just mixed a handful up during one of those late nights testing or it possibly went bad on me since then).
So, my question is, now that I've got all these packs welded up with fuses and tabs soldered to busbars, essentially all completed with not so cheap terminals and materials, can anyone think of a way to locate the self discharging cell(s) in the pack of 100?
The only things I can think of, without having to undo the entire pack, is to maybe point a thermal camera at it and see if maybe one cell is hotter than all the others? But I'm also pretty dumb so I'm not sure that the cell would register a higher temp, even if I happened to have a nice FLIR camera (which I don't).
I suppose I could also undo the fuses on the positive end one by one, checking the current running to each cell with a multimeter then (I do have a DC clamp meter but no way in hell I'll get that clamp just around one fuse leg). I'd also rather not make a brand new pack of 100 but, honestly, that may be the quickest solution. I'm hoping against hope there's a better solution that's been mentioned on this board that I just can't seem to find, so if anyone knows of it, I would greatly appreciate it. I shall send you a 12 pack in the mail.
And sorry for a new thread for such a specific, selfish question, I tried searching for a like minded existing thread or post but came up with squat. Thanks for the help and time guys!
TLDR: Any ideas on how to find one cell in a pack of 100 that's self discharging/parasitic without taking apart the pack?