What's up with the battery?

I've been using my Canon G1 quite successfully for many, many months and many, many pictures. My battery finally died last week (no warning), so I went to the Battery Barn site and purchased another battery (not the Canon battery, but one that's supposed to last longer). Now the camera won't take more than about 25 pictures before it shows me the low battery icon, and then the display screen won't light up anymore. I recharge the battery, the light goes from orange to green after several hours, and the whole problem repeats. Do I have a dud battery, or is this a camera problem? In the past, I could take 200 pictures in an afternoon without any problem whatsoever, and the power was still going strong. Now I'm lucky to get 10 minutes out of it before I'm out of power. What's up?

Mimi, contact Battery Barn - I bought one from them - no problem with it. 'Lanmar' or something like that. Also, I had 'battery trouble' sometime ago, and the 'firmware' was updated by Canon (free) to 1.0.0.3. You should check your camera. Connect your camera to Zoombrowser (use mains power if no battery power). You can check what version of firmware is in your G1 through one of the menu options...I can't just recall which. Someone else may advise.
Goodluck