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View Full Version : Strange Lithium-Ion behavior


CobraGeek
2008.02.26, 11:54 AM
I just upgraded my monster to lithium-ion. I purchased the parts off ebay and put it together myself, but it's not complicated. I followed the directions off jaw-drop racing's page. I have 2, 4/5 AA 650mah batteries hooked in series. The problem is that one cell discharges MUCH faster than the other.

When new they were both 3.8V. I hooked them to my 2 cell charger (which unloaded supplies 8.2V, but with the cells hooked up peeks at around 7.6-7.8V. They appeared charged. I ran the car until it would no longer wheelie and strangely the left cell was at 2.2V and the right one was at 3.5V. Yes, 2.2V is bad and that cell was pretty much dead.

So I bought a couple more cells and used one to replace the dead one. This time I watched closely and after about 10 minutes of running both cells were still in pretty good shape, but the left one was down a bit more than the right one (3.6V vs. 3.7V). but after another 5 minutes it was 3.0V on the left and 3.7V on the right. It still charged up OK and was still doing wheelies, but the left definitely discharges faster. The next run only lasted 10 minutes before the left was at 3.0V and the right was still 3.7.

Do any of you have any ideas why this might be occurring? Should I replace the right cell too? Any other ideas?

Thanks! -Bret