Originally Posted by projectorkid
battery from 7100 CS-1 works perfect in 8700c. Note CS-2 battery is square vs CS-1 which is more round on the edges. CS-2 lasts much longer
I'm going to have to disagree.
The C-S1 battery will display a Battery icon with a slash through it. The new generation BB's are specifically designed to only work with the secure batteries.
Aditionally the C-S2 is only rated at 100mAh more than the C-S1... so "much longer" might be 5-10% IF in fact it worked... which it does not.