R/C Tech Forums - View Single Post - Is it better to build packs based on runtime or average voltage?
Old 12-29-2003, 02:29 PM
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seaball
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i think the question is more about the importance placed on matched #'s versus high numbers. ya'know?

i would think that matching based on runtime, or capacity would be more beneficial since each cell would want to peak at or near the same time, leaving no cells with a partial charge. would the repercussion to matching this way would be that the pack may only stay matched for a short while since the voltages of each cell may push charge back and forth among its neighboring cells? i dunno.

total average voltage is just that. add em up, divide, and that's your average pack voltage. if i had a choice between a matched 1.16/400sec, and six cells that were between 1.16 and 1.19, all at 400sec, i'd choose the mismatched votage pack since the average would be near 1.175 (middleground) and the pack would still dump hard and steep.

it just seems clear to me that if you have cells all over the place for capacity, you'll never run with a full charge regardless of what extreme voltages the cells may have, unless you charge each cell individually. what's the point of high numbers if the cells don't get charged completely. the first 20 seconds of the discharge contribute heavily to the numbers. w/o that initial section of the discharge curve to average, you'd be surprised how bad a pack will look.

this is a good thread. and i sure hope more people, with more knowledge on the subject than i have, stop in.



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