I now started building my selfmade charging device. The electric-circuit is finished (and works) but there are problems with the case... (This f*****g german electronic online shop has wrong descriptions of its parts and now the battery pack is some mm too big for the case and it has to be external.)

here a pic:



The good thing: with the snap-fastener I can connect every size of battery-holders.

I even could test it: 3:05 hours runtime with a completely empty internal battery, 4 external AA batteries, display and gps running. I noticed, that the internal battery doesn`t get charged - its power level is at about 0% all the time (read out with kcbatt).


Thats really bad efficiency. I`ll have to try the direct version. Just ordered two verry cheap BP-4Ls from Hongkong (just for the connectors to build a dummy for the internal battery leading out the cables to power it external).

In theory (I know there can be other loss or the device shuts down before the batteries are completely empty if the voltage drops to low) 3 AA batteries with about 2800 mAh should be able to run the device 1,8 times as long as the internal battery (1500 mAh). With the internal battery its runtime with display and GPS on is about 4 hours. So it should be 7,4 hours (connected directly without charging-loss)... I`ll give it a try.