We are rigging up a power cord for a cordless drill for work. This is necessary because the batteries are starting to die on some of the models. We rigged it up so we can plug the drill into a variable DC power supply. We can control the voltage and amperage output on this power supply. When we match the batteries amperage and voltage output to the dc power supply the batteries power seems more instantaneous. The battery power causes the drill to start instantaneously with full power while the power supply takes more time to reach to the same RPMs as the battery. Also, the power supply does not supply the same torque as the battery did, this was seem while screwing in a screw and the battery was able to screw it all the way into a board while the power supply could not make it all the way. Then we decided to install a capacitor to the power input to increase the response rate, but to no avail. The voltage of the battery is 2.4 V and we have cranked the amps and the voltage up to try and get the same response to no avail...any help in describing why this happens would be greatly appreciated. I know this is a physics problem because the wiring done it correct.