I have one of their 1400 packs in my revo. Running 2 Jr650 servos in it, after a tank and a half the truck does absolutely nothing. No twitching, no movement at all. Did the same thing yesterday, but when I charge I can only get about 600mah into it. Has anybody else used these, or seen or heard of similar problems? Do you think if I contact MaxAmps they might replace it? Thanks.