I have the V551 and this battery fully charged, lasted aobut 8 hours. I go to work and don't even talk on the phone, I get off and it's down to 1 bar. If I talk anytime during the day it'll shut off before I get home. I wish I could get 3 days out of this battery!!! Oh and I had Amazon send me another thinking the first was a defect...NOPE! 2nd one was just as bad. Shell out the money and get a name brand battery...that's what I'll end up doing.