I just set up my 2.4 Volt Mod on my new WRX. I also have a 3 Volt charger set up to charge it. My question is about my run time. I charge it on the charger for exactly 2 minutes, but when I run the car it only goes for about a thirty seconds of super speed then drops to super slow. Why does it do this? Do I need to charge it longer? Do I need another, bigger charger?