OK. When you get it fixed, I'd be interested to read if also in practise can be charged through N900 microUSB and N900 software doesn't go nuts because it takes longer time and resistance may be little different that with single battery.

[Some manufacturer could make tiny enough "pass through connector", so 1st battery still would fit in and 2nd battery would nicely clip on top of it to its own 2-pin connector.]


I'd be most interested in a DIY mod, where there would be another battery connector coming from the case parallel and before the original battery connector.

N900 is disassembled
http://sites.google.com/site/svcr0c0/n900

In picture below the obvious place where two cables would be soldered is seen, A, under the original connector and then lead cables (+ and -) nicely through the plastic cover, making hole in the place B. The cables, extra connector and extra battery would be nicely under Mugen cover. Batteries would not need any modification and N900 would had only one small extra hole under the back cover if the hack would be removed later.