This is probably going to be similar to my Vpower/CammyCC repair thread here:
http://www.endless-sphere.com/forums/viewtopic.php?f=14&t=22750&start=45
except that this is a repair for RTLSHIP, whose pack drops by several volts not long after charging.
Based on his results, including a test he did of unplugging the balance wires from the BMS right after charging completed, and getting the same voltage drop then, it is likely to be a cell or cell-group issue just as mine (from Bluestreak) was.
If it were the BMS, it should not have dropped so far down after unplugging the balance wires from the BMS, as it could not then drag cells down (assuming a problem with the balance circuit(s)).
I suspect a bad cell dragging down a group, or a spotweld problem, or both.
Bonnie the chief inspector had to approve it upon arrival to the repair facility, of course.
View attachment 24
It was well-packed, and has not suffered any shipping damage that I can see.
View attachment 23
View attachment 22
View attachment 21
View attachment 20
View attachment 19
View attachment 18
Total pack voltage is 52.9V, across the BMS pads.
View attachment 17
I tested each cell (pics attached but not inline to make reading post easier) via the balance wires a few minutes after it arrived. I unplugged the balance connectors from the BMS and taped them to the top of the BMS for easy hold-down while I measured things. Note that the reading on screen is not the cell-voltage; I just noticed that it must've snapped the pic at a moment I didn't have good contact. It was the same as the next one up, 3.56V
View attachment 16
Also note that due to my arm being in the flash's path for most of the pics, it's a little hard to read the values on screen in these smaller versions of the pics.
There is only one cell group, number 6 from the most negative end, that is significantly different in voltage, and it reads very dead, at 0.75V.
View attachment 15
Marked on connector for easy locating next time:
and it happens to be the balance wire with the most blue markings, thus easy to trace, too.
Everything else reads about 3.48V up to 3.65V, with the majority at 3.56V or 3.57V.
More info later, after I begin disassembly to verify connections, welds, etc., and start determining the actual problem cell(s).
After that, I'll have to find a source for the cells to repair with; I have a couple of leads here on ES but have to see if they still have any.
View attachment 16
View attachment 14
View attachment 13
View attachment 12
View attachment 11
View attachment 15
View attachment 10
View attachment 9
View attachment 8
View attachment 7
View attachment 6
View attachment 5
View attachment 4
View attachment 3
View attachment 2
View attachment 1
http://www.endless-sphere.com/forums/viewtopic.php?f=14&t=22750&start=45
except that this is a repair for RTLSHIP, whose pack drops by several volts not long after charging.
Based on his results, including a test he did of unplugging the balance wires from the BMS right after charging completed, and getting the same voltage drop then, it is likely to be a cell or cell-group issue just as mine (from Bluestreak) was.
If it were the BMS, it should not have dropped so far down after unplugging the balance wires from the BMS, as it could not then drag cells down (assuming a problem with the balance circuit(s)).
I suspect a bad cell dragging down a group, or a spotweld problem, or both.
Bonnie the chief inspector had to approve it upon arrival to the repair facility, of course.
View attachment 24
It was well-packed, and has not suffered any shipping damage that I can see.
View attachment 23
View attachment 22
View attachment 21
View attachment 20
View attachment 19
View attachment 18
Total pack voltage is 52.9V, across the BMS pads.
View attachment 17
I tested each cell (pics attached but not inline to make reading post easier) via the balance wires a few minutes after it arrived. I unplugged the balance connectors from the BMS and taped them to the top of the BMS for easy hold-down while I measured things. Note that the reading on screen is not the cell-voltage; I just noticed that it must've snapped the pic at a moment I didn't have good contact. It was the same as the next one up, 3.56V
View attachment 16
Also note that due to my arm being in the flash's path for most of the pics, it's a little hard to read the values on screen in these smaller versions of the pics.
There is only one cell group, number 6 from the most negative end, that is significantly different in voltage, and it reads very dead, at 0.75V.
View attachment 15
Marked on connector for easy locating next time:
and it happens to be the balance wire with the most blue markings, thus easy to trace, too.
Everything else reads about 3.48V up to 3.65V, with the majority at 3.56V or 3.57V.
More info later, after I begin disassembly to verify connections, welds, etc., and start determining the actual problem cell(s).
After that, I'll have to find a source for the cells to repair with; I have a couple of leads here on ES but have to see if they still have any.
View attachment 16
View attachment 14
View attachment 13
View attachment 12
View attachment 11
View attachment 15
View attachment 10
View attachment 9
View attachment 8
View attachment 7
View attachment 6
View attachment 5
View attachment 4
View attachment 3
View attachment 2
View attachment 1