Forget the cordless use a 120 volt drill and you wont have any trouble. The
best way to build partition walls is to make them up on the floor that way you
eliminate most toe nailing or screwing which is weak. Take a few measurments
for height at various places and subtract and inch and a half from that
measurement. Make your walls up lying on the floor. When done stand them up
slide them in place and fasten the toe plate to the floor, then place a second
2X4 on the top and fasten to the ceiling joists when level.
This is the quickest and easist way unless you floor is way out of whack. In
that case you have no choice but to do it in place and toenail it. For this a
120Volt drill will work fine. I nail gun is even better.