RE: Volcano EPX Pro problem
it sounds like the ESC is going into lipo cutoff mode.
You can buy a 5000mah nimh battery from redcat...or a redcat dealer.
But your best option would be to buy a lipo battery. They are so much better than nimh its not even funny.
A good 2s 5000mah pack and a thunder AC6 lipo charger on hobbypartz.com will cost you about $75 shipped.
A 2s 5000mah lipo will ad 5mph to the top speed...as well as acceleration. And you will get 25-35 minutes of runtime!