



Discussion
Lets play 'guess the advertised capacity'
The initial voltage of the 3S lipo was 11.42 volts. The lipo was charged at less than 0.2 C. The lipo accepted 542 mah.
You know the formula for voltage and % full/empty for a lipo. Do the numbers in your head, or cheat and use a spreadsheet, and play "guess the ADVERTISED capacity" for this lipo. 




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Calculates to approx. 813 mah but tht would be an odd capacity. Charles 




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Brisbane
Joined Nov 2005
2,392 Posts

~800Mah




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Thanks!




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So tell me, if you calculated 800ish mah, how did you come up with an advertised capacity guess of between 1500 and 2000 mah? 




It is common for Vendors to rate capaicty and C much greater than their true numbers.
The industry standard for capacity is based on the 0.2C rate. http://www.rcgroups.com/forums/showp...13&postcount=1 Snip Quote:
The capacity game is much the same as the cycle life game. Manufactures graphs show 500 cycle ilfe but if you look closely the 500 cyclles are based on discharge rate between 10C and 0.5C and they do not say how many at each dicharge rate. Charles Charles 




Ok, now if I told you these were brand new cells. At what mah rating from the seller would you feel that you were given 'incorrect information'?
Lets see if I can be a little clearer. Given these cells are brand new, what would be the appropriate mah rating from the manufactuer? (or perhaps, at what rating from the seller would you feel 'ripped off'?) 



Charging mah into a battery of unknown initial charge (1/2 charge voltage varies from brand to brand) is of marginal value to calculate the capacity.
Discharge it at 0.2C and also at the maximum continuous duty rating and see what it gives you. The former might be over 100%, the latter probably around 90%. If it was under 90%, I'd be disappointed. 


Sydney, Oz.
Joined Mar 2006
441 Posts

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I dont see that the charge taken from 11.42v to (I assume) 12.6v has much to do with the total capacity claimed of the battery. Tell us what the battery delivered from 12.6v down to 9.0v and then I'll tell you what a reasonable claimed capacity would be. 

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