Battery technology changes fast right now. Most current laptop models use Lithium Ion batteries. These are really odd things. They store an insane amount of energy for their mass. Any time you have that kind of energy density its dangerous. These batteries have complex electronics inside their packaging that's designed with a number of fail safe circuits so they don't just burst into flame. As we've seen recently, they haven't always been successful.

I'd forgotten how long this laptop could run without a charge when I first bought it. I'd gotten down to 30 minutes and would have been happy with an hour. it's a dual core machine with two gigs of ram. The new battery I put in -- an OEM replacement -- gives me that original 4-5 hour charge again.

I'd like to keep this one performing so well, so I did some research. What did I do wrong with the last one? Is there something I could have done to make it last longer?

The short answer is No. I didn't do anything wrong. I just used it for two years. Lithium Ion batteries do not have a "Memory". You don't need to be careful of discharging them all the way then recharging. It does not matter. What matters is just how many times you use them. They're good for around 250-300 full charge cycles before they start show real serious deterioration.

That's it. If you use your laptop every day doing a charge/discharge cycle, your battery is good for about one year. No matter what you do, this is the case. There are a couple of things you can do to help the situation, but they don't change the basic characteristics of 250-300 full charges.

Here's some tips that I've been able to find at least two sources for:

1. Keep in mind, its 250-300 times. After that, you're seeing diminished results. For me, in two years, I went from 4.5 hours to 30 minutes. Replacement is the only solution.

2. Keep them cool. If you use them and they hit temperatures over about 60 degrees Celsius they will not last long. A laptop cooler is a good idea. Using your laptop on cloth, your lap, or a bed is not as good a plan.

3. If you plan to store them, discharge them to about 40% first. Don't store them long term with a full charge. I don't know why, but all the tech people agree its bad.