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johnrobholmes
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Join Date: Aug 2007
01.21.2008, 09:45 AM

My plan is to simply data log with two methods. First method is in a vehicle or sled pull. Burst currents will show the true burst rating of the cells (assuming enough amperage is drawn). Second method is on a test bed with a variable pitch prop and appropriate motor. This will give an easy to find continuous current rating. There will need to be a voltage standard set, such as 3.3v/cell under burst for "good" performance. Lower is poor, higher is excellent, etc. Same for continuous rating. All cells will need to be tested at the same temperature.

We will need to set a voltage standard and temp, as well as sampling rate standard for burst amperage measurement. Seeing as how most eagleltree loggers are 10hz, that is a fine sample rate. 95-100*f would be a good pack temp to start with as well. As for voltage standards, I would like input on that.


What got me thinking about this is the wild variation in pack sizes and weights between brands. For example, between two brands of 20C 4000mah cell there is 25gm/ cell difference and about 20 cubic mm volume difference. One brand is smaller and lighter, the other is heavier and bigger. My gut is telling me the larger and heavier pack will have better performance.
   
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