[NSRCA-discussion] LIPO Question

[Peter Vogel]

IT's actually I^2*R, not just I*R, but since the resistance is the linear
term here, you are basically looking at 2x the heat from Brand B vs. Brand
A.  The heat has to come from somewhere, and in this case that's battery
power that could have turned your prop and is instead going to
self-destruction via heat.

Peter+


On Fri, Jul 26, 2013 at 1:03 PM, Bob Kane <getterflash at yahoo.com> wrote:

> Without doing much math, from your note below Brand B is roughly twice the
> resistance of Brand A, so it will run hotter if run at the same current.
>
> If you want to do the math, the simple way is to measure the current at
> full throttle, then plug the number into this equation:
> Power = MaxCurrent * 1000 * Cell Resistance (in Milliohms)   This will
> tell you how much power is being absorbed by the packs. More power absorbed
>  is bad, less power absorbed is good.
>
> Converting power absorbed into temperature rise over time is more
> complicated.
>
> Bob Kane
> getterflash at yahoo.com
>
>   ------------------------------
>  *From:* J N Hiller <jnhiller at earthlink.net>
> *To:* NSRCA Mailing List <nsrca-discussion at lists.nsrca.org>
> *Sent:* Friday, July 26, 2013 3:30 PM
> *Subject:* [NSRCA-discussion] LIPO Question
>
> HELP!
>
> I'm trying to understand battery heat gained from internal cell resistance.
> Total resistance of brand A = 13, Brand B = 28 (Twin 5S 5000 packs - new -
> unused).
>
> Can someone point me to a formula?
>
> Thanks
> Jim Hiller
>
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-- 
Director, Fixed Wing Flight Training
Santa Clara County Model Aircraft Skypark
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