Using Bench Power supply to charge NiCd pack
Don't be fooled by early results when checking temperature.  They heat rise past 70% charge accelerates quickly from internal gas pressures and charge transfer inefficiency dissipates more heat.

from batt U.

Figure 1 shows the relationship of cell voltage, pressure and temperature of a charging NiCd. Everything goes well up to about 70 percent charge, when charge efficiency drops.  The cells begin to generate gases, the pressure rises and the temperature increases rapidly. To reduce battery stress, some chargers lower the charge rate past the 70 percent mark.

Therefore do not exceed 1.46V per cell * 13 cells = 19V



The charger from Dewalt is only rated at 18V with a current rating of 2A.

Dewalt DW9116 7.2V - 18V NiCd Battery Charger New for DW9057 DW9094 DC9071  $34.90 Ebay.

The fact that you need to drive 24V just to get 0.7A indicates your batteries have aged significantly and are on their last legs.

I know from past experience manufacturing and testing burp chargers this can rejuvenate NiCd batteries.  Can you make a pulse switch with low &lt;10% duty cycle at 24V ?  Then track your Amp-seconds of charge and useage and see if that improves it.

http://batteryuniversity.com/learn/article/how_to_restore_nickel_based_batteries

Which reminds me I have to fix my Hitachi LiPo cordless drill after left out in the rain.