Thanks, I have the Razr Maxx too. The guy at my local shop in Mobile told me that he thought the Ewerks cache battery would be sufficient, without using the charger, which he felt resulted in many fried devices due to failure to change the output with varying devices. The output on mine is 1.5 amps, which matched the phone and Kindle Fire for input. In re-reading the specs tonight on the Ewerks cache battery, I think I may need the charger after all, and that the cache battery alone won't work. Here is a link I found on the cache battery
http://www.starbike.com/p/Busch-M%FC...y-461A-4152-en
No, the Ewerk I have does not allow selection of output current. I appreciate your thoughts.