Will battery cycle count change with calibration?
I just bought a used battery for my wife's MacBook.
Her battery had 450 cycles or so.
Now I know I am taking my chances on a used battery from eBay, but the seller deduced that this battery has less than 100 cycles. He explains that it came out of a broken computer and is 'good as new.'
I plugged it in cold to her computer today and the cycle count was 732!!!
So I am going to calibrate the battery of course, but will my cycle count change after calibration? And if not, what can I do to determine the true cycle count? Maybe it is 732, but if it is, I think I want my 20 bucks back.
Good questions! I can't answer all of them, but you might want to download and install Coconut Battery and see what it says in terms of cycle count (consider it an impartial 3rd party opinion, if you will):
I'd have to guess that the 732 count is not correct, especially if it seems to be a good battery. Most batteries do not reach anywhere near that number, and are completely dead far in advance of 500, let alone 732. Also, I've encountered many batteries with various messed up numbers, and they were not necessarily bad batteries, so it's possible that despite the fact that it thinks it has 732 and it is obviously confused, it might still be somewhat of a good battery, with a lower actual count than that.
732 cycles-wow! As long as your showing a Full Charge Capacity of nearly 4800 mah then the cells are in good shape. The cycle count is held in the Smart Battery firmware. It is set to zero when the firmware is set up at the factory and is incremented by one every time the controller determines that a battery cycle has occurred (you can find this info by looking up TI Gas Gauge)
It will never be reset unless the battery is set up on the equipment used to set/reset parameters in the firmware. No big deal, it is just a counter. Remember the number that is was when you started using the battery, then subtract the current number from that number. It sounds like one of two things here. Someone could have taken an old battery and put in new cells in it, this would leave the old cycle count intact. Or, if this is an aftermarket battery that someone programmed in their basement and didn't set up the parameters correctly. Want to know more about your MacBooks smart battery? Just google 'charlie miller smart battery'. You can download the white paper and other info. I ended up buying a cheap aftermarket battery to replace my Apple branded battery. After about 40 cycles I started getting some really bizarre symptoms. So I pulled out the lipo cells from the new battery and attached them to the board in my old Apple battery - no problems since. (The cells in the Apple batterys and the after-market batteries are the same , Sanyo 2500 mah 3.7 volt set up in a 3s3p arrangement.)