PPRuNe Forums - View Single Post - 787 Batteries and Chargers - Part 1
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Old 24th Feb 2013, 21:56
  #810 (permalink)  
syseng68k
 
Join Date: Jun 2009
Location: Oxford, England
Posts: 297
Back at the beginning of the thread there was detail about the BMS using a
patented system that managed the charging of the cells using software that
predicted the temperatures from the voltage across the cells. It would appear
that 'patented' is not the equivalent to validated as working.
Actually, the patented method doesn't look at temperature, but fwir, tracks
the voltage curve towards the inflexion point. Then when it gets a match
with an internal model of a cell's charging characteristics, predicts end of
charge from that. Might be a very good idea, but is a bit simplistic in terms
of what else needs to be done to properly manage the cells. While temperature
and voltage are loosly related, you can't predict temperature from voltage
alone. Edit: In fact, you can't predict temperature with any degree of accuracy
at all.

It's much easier and more complete to measure each cell's temperature and
voltage, since they are the critical limiting factors in terms of maximum
charge or discharge currents...

Last edited by syseng68k; 24th Feb 2013 at 22:09.
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