Thread: Discussion A simple LiPo performance tool
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Old Jan 26, 2012, 06:56 PM
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You seem to be playing your usual game of changing the discussion to have it on your own terms.

No one ever claimed this simple technique was about a precise way to measure particular battery performance in flight.

Which part of

"The forums contain a wealth of information about battery performance from respected regular posters who have devoted enormous energy and time to creating a valuable treasure trove of battery data; and if you are serious about battery performance and want to have the best possible understanding of how your cells will perform you need to spend time with the test data."

from the first post didn't you understand?

Put bluntly:
1) The current labelled values of C are largely irrelevant and for people who neither want nor need a lecture in battery characteristics downright misleading. I don't see anyone disputing that.
2) A couple of people with a great deal of experience in practical battery testing and usage have suggested a very simple technique that anyone can use that may be significantly better. If it proves even reasonably accurate it will be extremely valuable.
3) It is just a rule of thumb, and like all such rules may prove inaccurate, or there may be cases where it doesn't work. I thought that would be the case for very small cells but so far I have been surprised by the results. However it wasn't developed in an armchair. It was developed by two people (not me just to be clear) who have spent a great deal of time ACTUALLY LOOKING AT BATTERY BEHAVIOR. If you have similar data to contribute it would be welcome.
4) The only way to find out is if people correlate the predictions it makes with what happens in practice. The very essence of a rule of thumb is that it gives useful predictions of behaviour without needing a detailed analysis of the underlying phenomena. Much of what we take for granted in our lives was developed that way - sometimes giving it an air of precision by calling it a "Factor of Safety".
5) This thread was an attempt to start that process of discussion and debate. I think it was a case fairly put and described and so far what have we had - a bunch of the usual nitpicking questions from you and microwave "Why not this, why not that?" and a stupid discussion about how to write Celcius temperatures - which was an entirely sensible point by HarryD and promptly addressed.
6) So here's a suggestion about how to return to the armchair discussion which you so clearly love.

Go start your own thread entitled "Problems and Issues with the proposed LiPo performance tool."

I will be happy to contribute positively and it may well turn out to be really important.
Quote:
Originally Posted by LeszekJ View Post
Returning to the armchair discussion which some of us dislike so much...

How do you understand "performance"? If you automatically think about "punch" or "climb rate" I'm with you at the moment.
Cell power loss = 6*capacity is not a straight performance indicator. Of course, it may help to protect battery from overloading and resulting overheating. It is also very important, I know by experience.
However simple limit of voltage drop is much better as an index of performance.
For instance: max amps = 268.3mV / Ri
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