Originally Posted by
seastar
Not to start an argument but you both missed the point.
Our batteries will barely start the engine under ideal conditions. The battery needs all the help we can give it.
The device I bought/built is for short time use in the winter between flights.
The simple fact is you do not need to desulphate (ie - remove PbSO4 from the plates) if the battery is not allowed to discharge when unused. Hard PbSO4 forms on the plates of unused discharged or partially discharged batteries, not on fully charged plates.
The HF battery tender applies about 13.4 volts to a fully charged battery and that is about the ideal float voltage for the AGM batteries used in our airplanes and will keep the battery just about fully charged.
By my measurements, it is also current limited to less than 30 ma.
That level of current (C/800 rate) through a 24 AH AGM battery will not "fry" it even over several months.
Most motorcycle battery maintainers that I have examined have a much higher charge rate and are not suitable for this purpose.
I am a EE with 40 years of professional experience designing and using devices powered by and charging all types of batteries including all types of lead acid cells.
I contend that my adaption of the HF "charger" is a technically correct and economical solution to keep my battery ready to start the airplane during low use periods in the winter.
I thought other CC owners might also find it a useful low cost and simple solution.
Bill