Nathan Mann (Yahoo!, FZ10 group, 29 June 2004)...
The FZ10 external power jack is spec'd at 8.4 volts, not the 7.2 volt rating of the internal battery.
According to Panasonic, the difference is due to the internal voltage regulation & filtering within the FZ10, which would be needed when plugged to a less than ideal AC adapter/DC conversion. Of course the circuitry would not be needed if one only used a true DC external power source, but that's unrealistic.
Therefore, anyone constructing an external AA battery supply should plan on using seven (7) NiMh rechargables to attain the correct voltage.
In the United States, Radio Shack has all the necessary parts -- AA battery holders for 2 or 4 batteries, as well as the wire and 4.7/1.7mm tip needed for construction.
On mine, I glued two 4-AA holders together and wired them in series. I added a 4 foot 2 conductor cable with the proper 4.7/1.7mm tip. I used a dummy battery to jumper the 8th battery position, so only 7 positions are active.
The whole thing fits nicely in a small/old camera belt pack, with space for extra memory and...another battery kit for {my} Vivitar 283 flash.
Will the FZ10 operate on an external 7.2v source? Yes, for a while, maybe. I also rigged an Remote Control Hobbiest 7.2v NiCad battery pack up to my FZ10, and it did work, but possibly due to the initial over-voltage on the NiCads due to a fresh charge. I have not compared a 7.2v 2000mAh NiCad pack to the 8.4v 1800mAh NiMh AA pack to see where the NiCad voltage drop-off cuts the FZ10 off. I actually have a mix of 1800-2300 mAh rechargables, and I do not worry about mixing them.
As always, be sure you have correct polarity on the external power tip before plugging in your FZ10.M Arnold, of CameraShed, describes how to make a battery pack for the Fuji. This provides a 5 volt supply, and will be need to modified to provide at least 7.2 volts. More interesting is part 2 of the project, which describes how to make a battery monitor. I am not sure, but this part of the project may also need to be modified for the FZ10 with the help of LM3914 datasheet.