Li-Ion batteries, what are the differences?

I just had another of my laptop batteries fail on me, and I thought instead of spending another $130 I’d see about replacing the cells. I now have 2 dead batteries, so I opened one up.

Inside I found a tiny control board and 6 18650 Li-Ion cells in 3 pairs of 2 in parallel. From what I’ve read online this is pretty standard.

Having checked the usual sources online, I’ve found the cells cost $6 each for “made in China” or $15 for “made in Japan”. Is there really that much difference in what you get? I also seem them rated at 3.6 or 3.7 volts in different brands (independant of country).

The notebook is a Mac Powerbook, and the original batteries were recalled because a couple of people had them explode, and it turned out the recalled batteries used Chinese cells instead of the Japanese ones that Apple intended (due to poor quality, there were impurities in the electrolye which shorted out the cells internally and caused them to explode).

So I’m left with a choice of Chinese cells for $36 vs Japanese for $90 (in which case maybe I should just buy the new battery complete from Apple). Anyone have some insight into the differences? And what about the different voltage issue?


One thing that the Control-board does is send information to os x on how much juice there is left in the cells. I failed to “calibrate” (load it full,unplug, wait untill it goes to sleep,fully recharge) So mine does think I have more power in the cells then I actually do.

This might be a problem to you though, with the control board thinking that it has less juice then it does.

If you find a way to reset the control-board memory I’d be happy to know!