Im looking into getting a new phone to replace my SG SII, im replacing it due to battery/charging issues its developed over the last 6 months. Basically it doesn't keep track of accurate battery levels, keeps charging for 10% or so after its unplugged, randomly turns itself off and when doing so also kills battery to near 0%.
Example phone is at 90% just took off charger, slowly creeps up to 94% charge then turns itself off 5 min later(mostly turns self off within 30 min of coming off charger), I let it sit for 60 min in a completely off state, calls go straight to VM, phone responds to zero button input but when I turn it back on its hot enough to cook eggs on and reading less than 5% battery levels. It does this with 9 batteries so far that ive tried from 6 different manufactures so safe to say its the phone not the batteries.
I have had this same exact problem with an HTC Sensation. I think it's a problem at the phone motherboard level as I have also tried different batteries. It only will reliably work when plugged in