I have noticed since software version 2.0 that any charger not plugged into a wall is much slower. My car charger, Richard Solo battery pack, and even PC usb charger seem to work much slowerrrrrrrrrrrr
I've got a Belkin that is pretty slow, too. Perhaps a bit faster than USB charging, but definitely slower than the AC adapter.
It all depends on the current output. The iPhone battery has a 1400 mAh battery. Most non-AC chargers put out about 600-800 mAh, so it's gonna take about 2 hours to fully charge. Check and see if your Griffin gives a power output rating.
I noticed you bought the PowerJolt SE, while the griffin website shows compatibility with iPhone, if you look at the 'Powerjolt' product (the one that charges anything with usb connection) it shows compatibility with iPhone 3g.
I'm just wondering if this makes a difference? Maybe the normal Powerjolt has better output? Anyone know?
I've got the Griffin car charger and it seems to work very well charging my 3G. I can't say how long it takes to charge fully because I rarely drive distances that would require that much time but I'll try and test it out somehow.