External battery for timelapse photography?

[Bad Navigator]

Does anybody have a suggestion for an external battery to use for extended time lapse photography? As it stands, the battery only allows roughly 400 shots before dying... Any info would be much appreciated!

 

[ivanouchkine]

I used the sector adapter plug of the GH1, linked some AAA batteries to it in parallel and it works like a charm. You might also buy this kind of product, but more expensive:

http://www.bhphotovideo.com/c/product/655687-REG/Switronix_XP_DSLR_P.html

Voilà !