Anker 2050mAh extended battery (same back cover)
Alright so recently I purchased the [url=http://www.amazon.com/gp/product/B0078WL4YO] Anker 2050mAh battery. It's compatible with the T989 (Hercules) and I727 (Skyrocket). It fits in the standard battery cover.
Like my previous Anker batteries, this one arrived with 66%. I used Juice Offender to drain it to 0%, and then fully charged it.
I later used it moderately throughout the day and it lasted about 16 hours. 4 hours on 4G and 12 on Wifi. I DON'T have screenshots though. By moderate use I mean quite a lot of texts, IMs on Facebook, checking Facebook every half hour, about 30 pictures taken in 8MP resolution (without flash), a few quick calls with Google Voice, a bit of web browsing, about 30-45 minutes of gaming, and a few YouTube videos streaming on 4G in high quality.
The next day, I used it on a full charge. The screenshots are attached. I used it moderately/heavily this time. About 3 hours on 4G and 10 on Wifi. More texts, IMs, pictures, 6-7 minutes of HD video recording, streamed more YouTube videos in high quality on 4G, an hour of gaming, some web browsing and dictionary use, and 2 very short calls. As you can see in the screenshots, my phone was awake quite a lot.
NOTE ABOUT THE SCREENSHOTS: The battery isn't at 81%. It really died, and when I put my stock battery in, the battery stats continued (which is really strange) so that's when I took the screenshots. If you look at the chart you can see it went all the way down and then a sudden rise up to 81% at the very end.
Note 2: When Wifi was on, I was using Wifi calling, so the phone signal was turned off.
Note 3: This is on rooted stock ROM + stock kernel, with almost all bloatware removed.
Here you can save money by buying two batteries + the universal Anker battery charger
. The charger can charge almost any smartphone battery by lining up the metal contacts properly. It can take power by plugging it in a wall outlet or by a USB cable connected to a PC or wall outlet. It can also charge a phone by connecting a micro USB cable from it to the phone. So you can charge two batteries at once.