Are you referring to this:
I tried it and it didn't work. I first tried it with my battery power at 60%. I put my Mogul in sleep mode with no apps running, plugged in the charger using a fresh Duracell, and waited two hours. When I checked it, it was still at 60%. But about two minutes later it dropped to 30%. WTF!?!?! I tried it again the next day at 50%. This time the battery level stayed at 50% for a little while before dropping at a normal level. I have the 1% battery meter .cab installed. So the only thing I can really say is that it kept my Mogul battery from discharging while in sleep mode, which isn't very useful. Maybe I got a bad charger.
I ended up buying a second battery. It's actually easier to carry than the emergency charger. It's a pain to swap batteries, but I've only had to do it once. If you are runing low on battery power on a continuing basis then you'd be better off getting an extended battery.