I should learn not to trust the % on my battery

[revaaron]

So I left my iPad 2 and HP TouchPad at home and left to FedEx to ship a package. All I had to do was look up in an email the address to ship a package to. I left home with 26% battery life. Mind you, this was my 3500MAH battery. 5 minute drive to FedEx and I was at 13%. Got inside and the phone started rebooting. One reboot and it was at 8% and then it just kept shutting off over and over again. After 30 minutes of fighting with the phone/getting my 1/2 charged original battery from the car, I got the address and shipped my package. It is terrible that no matter what ROM or battery or battery calibration or phone (my phone was replaced once), I still have the issue of the battery % just dropping 20% on a reboot.