High curent charger not showing charge increase

[eelpout]

So I bought one of those new Griffin Tech PowerJolt's for the iPad, which puts out up to 2.1 amps of current. They say it's OK for iPhones and iPod's too. I have a jail broken iPhone 3G (Pwnage 4.0.1) on iOS 4. I got it for keeping a better pace with some nav apps that drain the battery like crazy.

It charges the 3G just fine BUT, the battery level percentage sits on whatever number it was when you first plug it in, no matter how long that is. I only know the new charge level if I either reboot the phone or oddly, plug it into a different power source.

I talked to Griffin about it and they said they didn't understand why it might do that. I've plugged a few HTC phones into it and they charge fine (including showing battery level increase). It's something to do with this iPhone. I'll have to try my wife's iPod to see what her's does.

So I was wondering if maybe it's the jail break. Anyone else have a high current charger on a jail broken iPhone?

The other thing is I saw a thread on the Apple support site where someone claims a Genius they encountered said NOT to use chargers with high iPad-level current on iPhones because you'll damage them. Griffin claims otherwise.

[Captinsmooth]

I would have to agree with apple on this one, using a high power charger will definitely decrease overall battery life. Just like using a car charger on your phone does, because of the extra power over heating the battery.