So I found this overseas battery that fits in HTC Eris and gives you about 40-50% more battery life than the stock. It is not a stock battery, but one from Japan and before everyone chimes in on not wanting to put non OEM products on their phone for the $10 it is a definate steal. Here is the ebay link: 2000mah Spare Battery for HTC Touch Pro 2 T7373 Dopod - eBay (item 390175067680 end time Apr-24-10 22:17:18 PDT) The only drawback to this battery is the size. The back door can close shut on the corners but leaves a little space open on the sides. If you use a plastic case for your phone then there is not a problem. Also becasue of the size of the battery, the volume buttons take some wiggling with to work. IT is no biggy for my wife becasue the volume bup button works well. It is the volume down button that you have to play with. She comes from a BB Curve were she was used to going 2-3 days without charging her phone. Now with this battery she can easily hit the 2 day make and maybe a little over without charging. I prichased the Seidio 3500 battery for her but she did not like the extra bulk. To describe the issue of the gaps on the side, I have posted some photos that were posted on XDA Developers site.