Has anyone tried to use rechargeable CR-V3 batteries with their Pentax
*istDS?

I bought a set of Optex CamPower NiMH 2.4V 2000mAh batteries at Future Shop.
Dropped them in my camera, but can only snap off a few shots before the
batteries wear out.  I've been using four rechargeable NiMH AA batteries and
they hold a charge for a very long time.  I have also used typical lithium
CR-V3's and they last forever.  But these rechargeable ones can't seem to
take the strain.

Anybody have experiences with these or similar batteries?  I'm wondering if
they are simply unable to handle the camera's power demands or if I'm just
unlucky and bought a dud set of batteries.

Thanks,
Ken