I've been fairly unhappy with the battery life of my G1. With the stock 1150mAh battery, I am lucky to get 12 hours out of it most of the time. I was once able to use 49% of my battery in an hour and a half by driving to a doctor's office and surfing the web in the waiting room… Bluetooth was at the top of the list of battery consumers, so be sure to turn that off if you don't need it.

I found a cheap 2300mAh battery at dealextreme.com. I've ordered lots of cheap gadgets and cables from them in the past, so I figured it'd be worth spending $11.22 at this battery to try it out. They ship their items, slowly, from Hong Kong. I think it took about 3 weeks to get the battery.

How long does it last?

I haven't actually run it down to empty yet. The first day I had it, I ran it down to 25% in a little over 19 hours. I had everything enabled except Bluetooth. I watched a little over an hour of video, listened to some SHOUTcast radio with Tunewiki, played a bunch of games, read email, and surfed the web. I tried to use the phone as often as I could. That last 25% should easily have put it over 24 hours, but I was tired and I needed a full battery for the next day.

Just how big is that thing, anyway?

I looked at a lot of batteries. Nobody seems to give dimensions. Unfortunately, I don't have anything terribly accurate like a caliper to measure this thing with. I did come up with an easy way to convey the difference in thickness between the stock battery cover and this new battery cover.

The top part of the battery cover that sits over the camera is probably identical in thickness to the stock battery cover. Just below the camera it gets thicker and it maintains that thickness all the way to the bottom of the phone. I was able to stack 3 pennies on the shallow side of the cover and it came out pretty flush with the deep side. My good friend Wikipedia tells me that a United States Penny is 1.55mm thick.

My math tells me that the thickness of my phone has increased from 17.1mm to about 21.75mm. That puts it just a smidge under the thickness of my old Treo 650. I think I can live with that.

Is it heavy? Does the cover fit well?

I may not have a caliper handy, but I do have access to a shipping scale! The stock battery came out at 25g; the beefy new battery came out at 45g.

The first time I put the cover on the phone it didn't feel like it was going to fit. I may have had to press it on a little harder, but it fits very snugly with no gaps anywhere.

Update 2010-01-06:

My phone has mostly been sitting idle the last few days and I forgot to put it on the charger last night. The battery use applet is showing that I've been unplugged for a few minutes shy of 39 hours, with 29% capacity remaining. The three biggest battery wasters seem to be Cell Standby, Bluetooth, and Phone Idle, all clocking in at 29%. Wi-Fi clocked in at 9%, Voice Calls at 6%, and Display at 2%. I was on the phone for about 45 minutes.

All the power-wasting goodies were turned on—GPS, Bluetooth, Wi-Fi, and Sync. It probably helps that I live about a quarter of a mile from a cell tower.