All cell groups are 3.2 or 3.3v after a 2 mile ride, but the last cell group is zero. This is a 48v 15 ah life pack, but it only seems to have 15 cell groups (I could be wrong) So my voltage is about 46 to 47. There are only 15 balancing pin plugs on the bms (11 and 4). I counted it 10 times! The pack is 8 yrs old but runs well when bms is disconnected. ideas or feedback appreciated. see pics
-
Howdy! we're looking for donations to finish custom knowledgebase software for this forum. Please see our Funding drive thread
BMS or Bad Cells
- Thread starter RTLSHIP
- Start date
All cell groups are 3.2 or 3.3v after a 2 mile ride, but the last cell group is zero. This is a 48v 15 ah life pack, but it only seems to have 15 cell groups (I could be wrong) So my voltage is about 46 to 47. There are only 15 balancing pin plugs on the bms (11 and 4). I counted it 10 times! The pack is 8 yrs old but runs well when bms is disconnected. ideas or feedback appreciated. see pics
If this is the same pack as
https://endless-sphere.com/forums/viewtopic.php?f=14&t=30864&start=75#p521073
then there's probably another dud cell in that group that has drained down the other cells in the group, so it could actually be 0V.
Even if it's not the same pack, it's still probably the same problem(s).
You'd need to measure at the actual cells under the wrappings to make sure the balance wire didnt' just break somewhere, which would also result in reading 0V (measured from battery negative to first balance wire).
If it is not the balance wire, and the cell group voltage is really 0V, then you'd need to use the techniques linked in that post/thread to determine which cell is dud, and either replace the dud cells, or disconnect one end of them from the group so they don't electrically interfere with the rest of the pack anymore, then use the charging techniques in the thread to fix the rest of the cells.
https://endless-sphere.com/forums/viewtopic.php?f=14&t=30864&start=75#p521073
then there's probably another dud cell in that group that has drained down the other cells in the group, so it could actually be 0V.
Even if it's not the same pack, it's still probably the same problem(s).
You'd need to measure at the actual cells under the wrappings to make sure the balance wire didnt' just break somewhere, which would also result in reading 0V (measured from battery negative to first balance wire).
If it is not the balance wire, and the cell group voltage is really 0V, then you'd need to use the techniques linked in that post/thread to determine which cell is dud, and either replace the dud cells, or disconnect one end of them from the group so they don't electrically interfere with the rest of the pack anymore, then use the charging techniques in the thread to fix the rest of the cells.
it's not the same pack. Sanges has that one and never returned it or the charger. I have taken this one apart once already but didn't probe, but your theory seems ok. My tinkering ambition is limited. This pack has been this way for 4 1/2 years. Maybe I'll sell it eventually.
Similar threads
