car not running long, and some charger help..

[tegboi]

hey, i have a TOMY bit char-G, nsx-r. i ran it stock with a 2.6 for a while, then did a dual nicd with the 2.6, then after a while, about 2 weeks. it started not playing for so long. (within the 2 weeks, i played it about 3 times) then now, i removed one of the batteries. so it runs one nicd on a 2.6 motor. and when i charge it for appr. 45 seconds using a stand alone charger, running straight from the batteries. it only runs for about 15 - 20 seconds. then now, when i charge it for appr. 30 seconds, it runs for about 5 seconds, then stops. does anyone know what it may be? also, when i was doing the batt. mods, i did alot of soldering, and im thinking it may have been the solder iron touching both (-) and (+) at the same time that might have killed the battery a bit.
can anyone help me with suggestions?

about the charger help..
while trying to build a stand alone charger, i lost one of the metal arms that connect to the bottom side of the car from the charger. does anyone know a alternative to having a charger? other then having the wires from a battery holder, and holding it to the connections on the car. or does anyone know where i can purchase just the charger station for it.

thanks in advance..