I have a Macbook CD 1.83 GHz which is about 11 months old. I calibrate my battery about once a month (the full charge and discharge) and haven't had any problems until about 2-3 weeks ago. When I am using my Macbook it says that I have about 10% battery left, then all of a sudden the laptop turns off. I don't get any message about running on reserve (which I used to get). When I plug the laptop into mains and restart, it says that I have 11%+ battery and it begins to charge. How can I calibrate my battery properly, as it appears that the internal counter is stuffed up and does not recognise that it is flat.

On another side note I have noticed that my battery health has been fluctuating between charges from 82% up to 98% and a few places in-between. Each charge/discharge cycle of my laptop seems to result in a lucky dip of battery health either increasing or decreasing by about 10% either way. Is there something I can "reset" to get everything back on track, or is this normal battery behaviour?

Thanks for the help.
Leon

see www.batteryuniversity.com

Get it replaced under warranty. Some Macbooks did have funny batteries. I got mine replaced because it's health was at 45% after 100 cycles.

I thought it might be a dodgy battery. Has anyone else on here had issues with the Macbook battery similar to this that was diagnosed as a bad battery. I would hate to take my laptop in and have them tell me that there is nothing wrong, or the problem can't be replicated.

That's pretty much EXACTLY what was happening to my blackbook battery (the health was yo-yoing, and it would cut off the power without going into deep-sleep). The MyMac Service Centre on Flinders st sorted me out pretty quickly. My new battery has 100% health after 17 cycles.

Yeah I've got a macbook and with iStats Pro it is showing some strange things with my battery: every time I discharge it completely then re-charge it the health is going down..... now at 68%. Guess a battery replacement looms on the horizon.

Basically if iStat shows the battery health is dropping, or low then it's a pretty good indicator the battery is stuffed. You can also see the battery health in the System Profiler. There should be no problem getting a battery with these symptoms replaced.

hahaha my battery replacement (which I got in may/june from memory) for my macbook pro due to the recall.. at 28 cycles, it jumps from 94-98%. Should I be fussed? it tends to sit at a 100% charge at least.

My problem is that the battery gets low (82%), then on the next charge jumps up to 92%, then it will go to 88% on the next cycle, then to 98% and so on. I have also noticed that when my laptop is working hard (CPU reads about 70 deg C), that my battery health decreases by about 1-2% every five minutes that the laptop is hot. When the laptop finishes working hard and begins to cool down, then the battery health stops dropping.
Guess I will book it in an get it fixed ASAP. Will this require a long time to get fixed or can I ring Apple and request a replacement battery and have it shipped out to me. It is just that the laptop is being used everyday for a project until the end of November, so a single day away is a really big deal.

Or this can happen too:
Fat MBP battery...

I had the exact same problem and have had it replaced no dramas at under warranty. There is a current battery replacement program through apple too for Macbooks your age

Just an update to this post. I have had my battery replaced under Applecare and everything appears to be back to normal.

Thanks for all the help.
Leon

I had this type of problem and i was procrastinating about sending it in, and cycled it a few times and mine fixed itself