Charging Problems on Sprint Mogul

[David737]

I am a EE and thought I understood battery charging. When I have my Mogul totally discharged, the Sprint HTC supplied charger works fine. When I use a third party charger with an A USB jack and a standard syncing or USB A to USB mini 5 pin connector it will not charge a totally discharged battery. My third party chargers with a USB A to USB mini 5 pin connector works great as long as the battery is initially over 30 %. It brings it up to 100%. Does the Sprint HTC supplied charger use different pins? If so, where can a purchase a USB A to USB mini 5 pin connector cable that would send the 5 volts to the correct pins? Any technical description would be appreciated. Thanks.