A few months ago I reported on a test of the BatteryMinder where I took a Concorde RG25XC that had been sitting around unused for two years after removal from my 360.  The initial recovery which started from 50% capacity rose quickly to about 80% in a few weeks.  The most recent check showed 86% capacity which I find truly remarkable.  It has proven to me that letting the battery sit inactive for the week or two between flights was very damaging and causing premature degradation of capacity.  Concorde's criteria for discarding the battery is the capacity falling below 80%.

Some have asked how I test capacity.  Not having an official, and expensive, battery tester, I use the poor man's method - a corn cob resister sized to give me the required 1C discharge rate.  Current is monitored using a shunt resistor and a high quality voltmeter.  I manually record current and integrate after reaching the cut-off voltage of 10V.

Chris

 

 

Chris Zavatson

N91CZ

360std