If you’re just into good home grown hacks this may be for you, however the acquisition of parts would cost the same $100 difference in the Droid Razr and the Razr Maxx. If there are after market batteries available out there somewhere this may be the way to go, but you may void your warranty and it your Droid Razr will no longer be sealed.
The good bunch of developers over at XDA have found out that the Droid Razr Maxx’s extra large, and extra capacity battery will fit into the Droid Razr and it will function beautifully. Because the Droid Razr Maxx is thicker, to accommodate the larger sized battery, your battery door won’t be flush.
The developers that discovered this home brewed hack replaced the battery and battery door on the Droid Razr. Once they removed the battery cover for the Droid Razr, they put the Droid Razr Maxx’s battery into the Droid Razr. They were able to use the battery door from the Razr Maxx to get the battery to fit over top of the bigger battery once it was in the Droid Razr.
More after the break
The end result was a small gap between the sim card door and cover which would potentially allow water and dust go get into your Razr.
Once they restored the door onto the Droid Razr they found that they got nearly double the battery life as the original battery, as expected. The problem is obvious though, you need the battery door and the battery from a Razr Maxx, so unless you can find one that’s been junked out or buy one off of ebay that has a broken screen, you may not have the opportunity to even try this.
This particular mod is RISKY so proceed accordingly. Want the directions, click this link to XDA. Wardo5757 gets credit on this