checked out the two batteries and the 6 cell looks the same as mine whereas the 12 cell has a different casing/shape but as you pointed out and the website says, should be compatible with Satellite U500.
I would be interested to know how much added time I would get from a 12 cell compared to 6 cell. Going off the mAh's (7800 vs 4700) should get 60% more time on 12 cell. Just wondering if it's worth the cost.
Well, usually the battery working time depands on the notebook usage.
The battery would discharge much faster running high performance appclations like games…
But 7800mA battery provide about 65% more power than the 4700 battery… so if you use the notebook a lot on the road, then 12cell battery is worth the money