Battery Cycles and Battery Health

But I really don't see how I could have that many. I rarely use my computer without the power cord!

From where did you buy your MBP? The reason I ask is that there are instances where some less honourable resellers sell either used stock (sometimes demo units) as new else a used battery has been swapped for your new one. One should always check when their MBP (or any laptop for that matter) battery cycle count is at a minimum in the single digits, as in less than 10. In reality the cycle count when new should be either 0 or 1.

Otherwise, the less cynical explaination is that there's something wrong with your battery. Reset the System Management Controller…

http://docs.info.apple.com/article.html?artnum=303319

… do a calibration and then monitor how quickly you accumulate cycles from that point onward. You should be accumulating them very slowly given your stated battery usage.

8 cycles in 10 days is reasonable if you are running on the battery all of the time. I get about 2:45 per battery charge. Are you using the battery for most of your usage?

See this link

http://www.apple.com/support/macbook_macbookpro/batteryupdate/

which mentions that the battery warranty is up to 2 years for core duo maachines.

A charge cycle means using all of the battery’s power, but that doesn’t necessarily mean a single charge. For instance, you could run your MBP for a 1.5 hrs on battery one day, using half its power, and then recharge it fully. If you did the same thing the next day, it would count as one charge cycle, not two, so you may take several days to complete a cycle.

Clear?

Each cycle reduces the longevity of a battery by a small amount.

191 cycles since August is heavy usage. If you got your new battery at the beginning of August, you've had it for ~70 days. So with 191 cycles, that's ~2.75 cycles +per day+. It's possible to do this if you run on battery until low, plug in to charge, then run off battery again, etc. Is that how you are using your MBP? If so, you will wear out batteries fairly fast!! If not, I would contact Apple...

(For comparison, I got a new (replacement) battery in late July, and I have 11 cycles on it. I only rarely run off battery, though.)

Hope this helps...

Just to build on what neuroanatomist posted. One cycle is considered a full discharge and full charge. This does not have to happen all at once. For example... if you start with a fully charged battery (100%), use it until the battery is down to 90% (meaning you have used 10% of the battery charge) and then charge it back to 100%, this would be 1/10th of a cycle. You would have to do this ten times before it would be considered a full cycle. Likewise... if you start at 100%, use your battery until it is down to 50% and then fully charge it, you can do this twice in order for it to be considered a full cycle. Basically any combination adding up to 100% is considered one cycle.

Having gone through that... If you got a new battery in August, I don't see any way for you to have 191 cycles under normal use. Did you get the battery directly from Apple? Did you happen to check to cycle count when you first got it... just to make sure it was at zero? It almost sounds like a used battery vs. a new one. The cycle count does affect your battery health. After roughly 300 cycles, your battery will hold about 80% of the capacity that it did when it was new. This is still perfectly useful, but... if you recently got a new battery, you should be getting the full life out of it. Nearly 200 cycles is quite a bit of use.

If you are putting your MBP to sleep, instead of turning it off, to move from place to place but connecting it to AC as soon as you get there, you will be using the battery during the transport time. If the battery drops below 95% charge during the trip then it will begin charging when connected to the AC. About 18 trips (I'm assuming that it got more that a couple of % below 95 on some trips) would result in one charge cycle. Even so it's hard to see how you cycle count got so high in two months.

If I got a new battery, would it start fresh at zero cycles, or would it start with however many cycles I >had using my old battery?

BTW, my health is at 86% and I've supposedly done 4 cycles since the start of this post...normal???????

The cycle count is maintained inside the battery so it can't remember your old battery.

If your cycle count has gone up by 4 cycles in the time it took you to type your post, then you have a problem. It's not normal. It could be the battery or it could be the charging circuit in the MBP. Do you know anyone else with an MBP that would let you try your battery in their MBP to see if the same rapid increase in cycle count happens? I would not try their battery in your MBP since if the problem is in your MBP it would increase their battery cycle count. Do you have AppleCare since you appear to be past the 1 year warranty on the MBP? Apple would cover the problem if it's the battery but not if it's the MBP and it's out of warranty. The battery warranty was increased to 2 years.

I can't understand why the cycles get this high!

That makes two of us.

Could there be ANY other explanation that would drive cycles up the yin yang?

Apart from a faulty battery there's nothing that I can think of.

If I got a new battery, would it start fresh at zero cycles

A new battery should be at either 0 or 1.