dumbass
100 kW
After 5+ years my 2 24v 20ah ThunderSky packs act like their pooped out. On a full balanced charge they are having major voltage drop at only around 12 to 14a draw. I had a full set of 16 new cells that I was going to use to build a second set of packs. So instead of building a second set I used the cells to replace the tired one in my original packs. Something I noticed while changing the cells though makes me wonder if the old cells are really as bad as I think they are. These cells all have screw on connectors making cell replacement easy. But I noticed all the washers, screws and wire connections were corroded. Not really badly but maybe enough so they were taking in the charge but when asked to deliver high amp discharge they couldn't do it.
Before changing the cells I did a test by running the motor with the bike on a stand and applying the rear brake (I have a 750w Bafang mid-drive). Each pack has a CelLog8 on it so I watched them as I did this. At 1000w on the CA meter the all the cell bars on both CelLog8s dropped to zero. As soon as I let off the brake they popped bake to 3.2v. I haven't tried this again since I changed out the cells and cleaned all the connections though. It's a big risk for the controller blowing. But could it just be contaminated connections causing the cells to act defective?
I would like to do a full charge on each cell and individually load test it. I am thinking I need to do a high discharge load test on them. So what could I use for the load? I was looking at this at Harbor Freight. It's for 6v/12v but I think that's only if your interested in using the built in volt meter. I would think that a load is a load and it should work. I can connect my own digital meter to check the voltage drop while applying the load from the Harbor Freight tester. Right?
http://www.harborfreight.com/100-amp-612v-battery-load-tester-61747.html
Bob
Before changing the cells I did a test by running the motor with the bike on a stand and applying the rear brake (I have a 750w Bafang mid-drive). Each pack has a CelLog8 on it so I watched them as I did this. At 1000w on the CA meter the all the cell bars on both CelLog8s dropped to zero. As soon as I let off the brake they popped bake to 3.2v. I haven't tried this again since I changed out the cells and cleaned all the connections though. It's a big risk for the controller blowing. But could it just be contaminated connections causing the cells to act defective?
I would like to do a full charge on each cell and individually load test it. I am thinking I need to do a high discharge load test on them. So what could I use for the load? I was looking at this at Harbor Freight. It's for 6v/12v but I think that's only if your interested in using the built in volt meter. I would think that a load is a load and it should work. I can connect my own digital meter to check the voltage drop while applying the load from the Harbor Freight tester. Right?
http://www.harborfreight.com/100-amp-612v-battery-load-tester-61747.html
Bob