Toshiba 6-Cell Replacement Li-Ion Battery Pack for 10" Thrive Tablet (PA3884U-1BRR)
Review by CBStanfield "CB Stan" : Best recent investment

A typical flight for me is 5 hours and often I do quick turn arounds. Having the extra battery has been a great problem solver.
I would be the first to admit, Toshiba could assign an engineer or two to making it a tad easier to remove the back cover. Having accepted that, it's still 30 seconds more or less, and the new battery is in and I'm good for another 4 or 5 hours. These seem to recharge close to 100 % in less than 2 hours. Strong plus for Toshiba.
The battery being flat makes it a natural to slide in the sidepocket of the CaseCrown Faux Suede Zip Sleeve Case for Toshiba Thrive Tablet, which I also love. About $6 on Amazon ?? At least it was.
Toshiba could solve a couple of problems by making the tablet chargeable in a car or by one of the battery packs via USB cable. Til then, this is a reasonable alternative.
Probably wont be long before the non-oem battery makers come to market with this at an attractive price.

Toshiba 6-Cell Replacement Li-Ion Battery Pack for 10" Thrive Tablet (PA3884U-1BRR)
Review by J. A. Singer "NoClue-Really!" : Add 11 Hours to your THRiVE (20111011)

This battery complements your THRiVE beyond what can be written. You might think that 11 hours (and the THRiVE really gets 11 hours in our use - we have two) is really enough. "NOT!" There are times when charging the battery is just not possible. The spare battery is a wonderfull accessory to have. It is not all that big and it fits very comfortably in a backpack. Remember to put it in a ziplock bag.