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Old Feb 13, 2006, 06:31 AM
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Tony Rogers
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Bath, UK
Joined Sep 2003
2,198 Posts
Rod,

First of all can I say that I like the graphs and thank you for doing them. The profile that you have chosen is not dissimilar (in average discharge and peaks) to that in one of my aerobatic aeroplanes. I also particularly like the individual cell monitoring. I guess you will be developing a set of profiles to represent different types of flying (Aero, glider, edf etc.)? It will be interesting to see how temperature and capacity delivered vary from a constant current discharge at the average current.

I have never flown a pack at full throttle for the duration so I think this type of discharge is more useful than the constant current method. Capacity delivered, temperature and maximum power available throughout the flight is very useful. For example, it is good to see that a pack can deliver 90% of peak power at the end of the discharge as opposed to say 75%. (Both of these packs seem to manage about 90% of peak power at the end which is, I think, remarkable). I guess in an aeroplane with these packs, power would be down to perhaps 80% of peak (full throttle) at the end of the discharge because the current will have dropped due to the reduced voltage. However, the profile still gives a very good approximation to a real flight.

I have quickly compared the plots with the constant current discharges for the PQ2100 and a couple of things spring to mind.

1) The temperature profile is slightly higher than the constant 9C discharge as expected but not too much so that's good.
2) The capacity delivered by the PQ2100 is disappointing to say the least. Far less than the constant 9C discharge. Were these cells known to be degraded in any way?

I look forward to your future tests.
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