Hewlett-Packard says they have addressed the battery life conundrum with its new EliteBook, a laptop they claim has a battery that lasts up to 32.5 hours. I tried the HP EliteBook 8460P to see if it could truly last 32.5 hours as promised. The computer itself is a fully loaded enterprise laptop with platinum casing, powered Intel Core i5-2520M Processor and 2 GB RAM. Yet the battery included in the laptop runs about 10 hours. I discovered that the key to battery longevity is using more than one, and using a bigger battery. Once I used up the original battery, (it took me about 9 hours), I had to plug in the  fairly sizeable HP BB09 ultra-extended life notebook battery, which attached to the bottom of the laptop. This battery adds more than a pound to the weight and has nine cells that add 100 watt hours. Apparently this is the legal limit. If was anymore HP would have to ship it as dangerous goods. Yet it isn't just the battery that extends the power. The key to reach the 32 hour level is to keep computer operations at six or seven watts of use, said John Wozniak, HP’s battery guru. That can be achieved by reducing the number of times the laptop sends out wireless signals and by reducing the screen brightness. HP also made the Elitebook more energy-efficient by replacing a hard drive with a solid state flash memory drive rather than a standard hard drive, which improves battery life 18 percent. HP also found energy savings by using Intel’s Sandy Bridge GPU, which combine a microprocessor and graphics on the same chip and achieved another 26 percent in power savings. The biggest consumers of energy in laptops and tablets today are the displays, so HP put ambient light sensors on all of its EliteBook models. Those sensors adjust the display brightness based on how much light is available in a room. For me, I got back on my computer the next day, after using it for about 8.5 hours and had it on for an additional 10 hours. I became a believer the following day when I ran it for another 8 hours. The following morning it began to warn me the battery was low and I plugged it in. Still, I had to give HP some leeway since it had been on standby and still using energy overnight. It’s an impressive feat, no matter if I had to use two different batteries. What is more important to you: extra long laptop battery life, a lightweight laptop, or a thin laptop?