I can't help you with an original battery pack, but what I did was to purchase a 3500 mAh Tenergy six cell NiMH battery pack that was designed for high drain applications (SC type). I cut the pack in half to get two three cell series packs. Since I hardly ever used the low light function of the 9N, I did not miss it. The high output works just fine without the fancy head on the original pack which allows high and low output.