As far as I know the only battery that T-Mobile sells is the same as the battery that comes with the phone. (As a side note, it is identical to the battery that AT&T sells for the SGS2 Skyrocket.)

I bought a genuine T-Mobile battery on eBay for $25 + $5 shipping, or thereabouts (forgot the exact numbers.)

Beware of third-party batteries. There are two issues:

• The T-Mobile SGS2 and the AT&T SGS2 Skyrocket use a battery that has different dimensions than the battery in all other SGS2 phones. Be sure it specifically says it is for the T-Mobile SGS2 or the AT&T Skyrocket.
• The batteries in the T-Mobile SGS2 and the AT&T SGS2 Skyrocket contain the antenna for NFC communications. Even if you find some htird-party battery that is physically the same dimensions, it probably won't have the antenna.

An alternative is to get an add-on battery that plugs into the USB/charger socket on the bottom of the phone. Then you won't have to worry about the physical dimensions of the battery or the NFC antenna.

 

Have you cycled the battery a few times? What kind of times are you getting out of it now, with what kind of usage etc.? Seidio does have an extended battery and back cover, but it's a big hump and expensive. ( seidioonline.com )

 

Root the phone. I used to get only 6-7 hours. I now easily get 14-16 hours.

Once rooted you can do a number of things to make the battery last.

If you don't want to root (which I would recommend) you could try 2xbattery app from market. It works wonders.

 

Blue, how much heavy lifting do you do with your phone? I'm just curios as I'm running a Uni computer lab and all day on data, wifi, bt, music, with annoyingly constant texting etc... I guess I'm super lucky, but I seem to get great battery life. I'm starting to wonder if some of the OE batteries out there are just really bad.

 

I'm on my phone all the time. Twitter, messaging, rdio music steaming, and youtube. And answering questions on androidforums

Easily 14 hours. Some days 20 hours

 

I see, you're a busy guy! I guess being so long in the labs or studios cuts down on my actual talk time a lot, which I guess seems to be great for my battery!

 

i say I get get approximately 70 percent of my iphone 4's battery life. I guess im spoiled by that. i may try 2xbattery to see if that helps some.

 

oh,

is the NFC antenna the only difference between the aftermarket batteries and the stock battery? I was looking at picking up a few higher capacity batteries for traveling on my bike. i would not be using NFC then, so I guess i would be ok getting some!

 

No, the dimensions are different as well.

 

have you rooted your device? after loading a custom rom on mine..im getting about 14 to 16 hours of normal use..also mugen is coming soon with a 2k mah battery

 

Awesome....I searched ebay under tmobile g2..there was a bunch of batteries...they are all no good?

 

what is "rooting" the s2 and how do I do it? My battery life is not great, thanks!!

 

Here is a simple guide to root: http://androidforums.com/galaxy-s2-...oot-optimization-guide-steps.html#post3718113

Rooting is like jailbreaking: you are opening access to system files and apps that you normally would not be able to see or edit. You can freeze certain apps to improve battery and you can make modifications to the device that you normally are not able to do.

I would try the app 2xbattery. It made a big difference to my phone (root not needed)

 

I get great battery life from stock, my usage is different day to day so its hard to pin down the exact amount of hours I getfrom a single charge. I guess I charge it every 1.5 days. Surf, chat, games from Sentinal 3 to Angry Birds, texting, oh and phone calls too

 

I bought three Samsung batteries on Ebay for cheap. I hope they are real samsung but......

 

I would suggest get an external battery charger to carry around. There're many options out there

Amazon.com: micro usb external battery

I have the New Trent 7000mAh one. Works very well. Took it to several trips already that I don't have access to USB charging for a few days.

 

And they are good for other phones too. Just in case in the future you change your phone, you can still use this external battery charger, compared to buying second battery just for this particular phone.

 

how do i sync with my outlook email at work?

 

probably my best bet is to get a couple of external batteries. I have so many devices. I have 2 archos tablets, Ipad, Ipod, 3 iphones, my galaxy. If we travel all of that goes with us. So, it makes sense to get the external batteries....good call on that one! thanks!

 

This is the one I have. 7000mah with 2 USB ports to charge. One has a higher current for charing iPad. I like it the best compared to other similar product as it uses the same microUSB cable to charge devices and being charged.

Amazon.com: New Trent Arcadia Pack IMP70D 7000mAh USB External Battery Pack and Charger for iPad2, iPad, iPhone 4S 4, 3Gs 3G (AT&T and Verizon), iPod Touch (1G 2G 3G 4G 5G), Motorola Droid Phones, HTC Android Phones, Blackberry, Samsung Galaxy S, Sam

also here's my review
Amazon.com: T. Cheung's review of New Trent Arcadia Pack IMP70D 7000mAh USB ...

 

John Jason and Crystal,

Not to contradict you, but I just spoke with a Samsung representative over live chat a few minutes ago regarding this very issue and the answer that I received about my Galaxy S II Skyrocket is that the NFC chip is housed within the phone itself, not the battery. Why the battery says "Near Field Communication" on it if this is the case is beyond me, but, to me, the answer makes sense. Authentication would be a rather complicated feat for those who wish to make use of multiple batteries, as many are wont to do. If each battery housed a unique NFC chip, each battery would have to have a different unique ID associated with it, which would then have to interact with the phone.

Though I'm not 100% up-to-date on the technical workings of NFC, I do know that this is a possibility, as NFC chips require very little power to operate, but my doubts arise when I think about the chip's interaction with the phone if it is housed on the battery. I see no special contacts in the battery compartment of my phone that would indicate some sort of direct connection with the chip itself and I do not think that the relays that provide power from the battery to the phone would be an efficient data transfer medium.

So far as I know, all other NFC-enabled devices have opted to install the NFC chip itself within the device proper, not the battery, though Samsung is prone to wild flights of whimsy when it comes to design.

I will provide an excerpt of the transcript of my chat session with the Samsung rep. I should also note that, though the rep states clearly that the chip is inside the phone and no special battery is required to power it, he/she did not know whether a third-party battery would work with NFC functionality. My feeling is about 90% yes, seeing as no special power standard for NFC exists (as far as I know through my research), but you never know.

Transcript:
Visitor: My question is specifically about the location of the actual NFC chip. Is it housed within the phone or inside the phone's battery? If it is inside the phone, is a special battery required to power it?
Jamie: The NFC chip is housed with in the phone and there is no special battery required to power it. It works with the provided default battery only.
Jamie: Is there anything else I can assist you with?
Visitor: So as long as a third-party battery is designed to fit and work with my Galaxy S II Skyrocket, NFC features will work, once they are activated by Samsung/my wireless carrier?
Jamie: Yes, the NFC features will work with the default battery on the phone.
Jamie: Do you have any other questions?
Visitor: Yes, will NFC work with a third-party battery?
Jamie: I am sorry, as I may not able to provide you the exact information regarding that. However NFC works with the provided battery in the phone.
Visitor: Well, thank you for answering as much as you could.
Visitor: That's all the questions that I had for today.
Jamie: I am unsure if it works with the third party battery or not.
Jamie: You're welcome.
Visitor: I will continue to research, then.

 

So does anyone have any feedback yet on whether the cheap eBay batteries will work in the phone, and if yes how well?

Also could someone point out to me what NFC allows you to do (excuse the noobines)

 

Sorry to quote the entire long post, but there are several points that kimj2y failed to grasp and failed to ask the representative, and that the representative did not clearly mention:

1) Yes, the CHIP is inside the phone.

2) No, the NFC will not work with third-party batteries because the ANTENNA is inside the battery. Even if you find a third-party battery that is the same dimensions as the battery in the T-Mobile SGS2 and the AT&T Skyrocket, it is doubtful that they will contain the antenna.

If you want NFC to work, either buy a genuine Samsung battery for the T-Mobile SGS2 or the AT&T SGS2 Skyrocket, or take LunchBB's advice and buy an add-on battery.

And having said that, chips and antennas notwithstanding, NFC won't work at the moment anyway, because the software is not yet available.

Plus, I should add that Phandroid recently announced a new SD card that contains everything for NFC, which will make NFC possible on phones without an NFC chip or antenna.

 

Even with a genuine OEM battery, NFC doesn't seem to work with it. I assume its because the rom is used to the original battery and the change in antenna messes things up. I will test this out buy installing a rom from scratch with my spare battery to see what happens.