One other thing I wanted to point out is if one compares a typical 6.6 volt, two cell LiFe pack to a standard 7.2 volt, six cell NiMh pack, the LiFe pack looks a little weak. What is important to remember though is that we run our packs under a load. Sometimes a severe load, and under a load like that, nonimal voltage ratings drop off a lot with NiMh packs. Not so much with a LiFe pack, or LiPo pack. Your 7.2 volt NiMh pack might be capable of maintaining a 6 volt or less rating underload, especially as it reaches the point where it has given up half it's capacity already. At it's very near discharged state, a good NiMh pack might only be providing 5.4 volts or less. A LiFe cell will maintain it's 6.6 volt rating right up to the end of it's capacity. So even if you are worried about the LiFe pack looking like it has less voltage, it's more capable of maintaining that voltage, even under load. It really doesn't give any performance away to a NiMh pack like you could think. Don't just look at the nominal voltage ratings, in other words.
Now let's switch subjects. The forumla for figuring out a LiPo pack's max continous current rating is to multiply the pack capacity by the C rating.
Pack capacity is the mili-amp rating. The C rating is the discharge capacity, or how fast you can discharge the pack. To figure out the maximum continous discharge rating you have to multiply the C rating by the battery capacity. Example - a 2200 mili-amp pack that has a C rating of 10C.
Convert the 2200 mili-amp rating to full amps. One mili amp is .001, so we multiply 2200 by .001 to get 2.2 amps. Simple, right? Now take 2.2 amps and multiply that by the C rating, which is 10. That would be 22 amps, and this is the continous discharge rating for your pack.
Hope this will help.