I've come to bump on this excerpts where according to one of Google Engineer, deleting the 'batterystats.bin' won't really improve the battery performance or usage of your battery... I myself have tried this method of deleting the batterystats.bin using the recoverymode and also using the root explorer (/data/system/batterystats.bin) but I find it very interesting that Google acknowledged that this process doesn't really do much in getting an optimal performance on our battery...
Deleting Android's 'batterystats.bin' Won't Grant More Juice