Was this for a 1/18th Sidewinder or 1/10th Sidewinder? If 1/10th we do not state anywhere on the site that it works with 4 cell NiMH...only gives the "up to" ratings. Did you assume 4 cell operation was ok? Contact us prior? Trying to get a handle on the whole situation. Sorry it's taking time to get back to you. Been hectic at work lately.