The Accucycle seems to have problems with cycling NiMh's... better to just slow charge the NiMh's and don't worry about it.

If you open the battery up far enough... the 3rd wire will most likely just end and do nothing. Some packs will have a tap-in for a lower voltage, but for R/C... we just don't use it. To verify that you are connecting correctly, check with multimeter and use the leads that read the highest.