Because the battery of the bold 9790 is not so amazing I decided to buy an extended battery to recharge the bold 9790 when I am not near a computer or a power line.
Unfortunately that extended battery is not working.
I would like to know if someone could publish the specs of the output power to find another extended battery.
Some of the after market batteries need to be calibrated for your phone. Many will include the device that is required for this procedure, unfortunately some don't.
Ike1, I think what you are referring to is commonly called Portable Mobile Booster, or also called Powerbank. The one you bought might be faulty or not compatible for 9790.
It is more simple with no USB cable needed. Very efficient and surely powered my 9790 for 24 hours and more. You may to consider looking for this product in your country.