On Wednesday, June 20, 2018 at 9:27:33 AM UTC-4, OHM Ω http://aviation.derosaweb.net wrote:
Andy,

I have used the ideal diodes mentioned by Shaun McLaughlin (http://re-voltage.eu/ US$27 each) as I was given a pair to test with. They do what they say with minuscule voltage drops across them. Full disclosure, I am currently using two 1N5821 Schottky diodes in my panel right now (page 74 of my presentation) - small, simple, cheap, plentiful, robust, and easy to mount..

That being said - the availability of inexpensive ideal diodes has exploded in recent years mainly for use in systems like solar panel arrays. See https://www.ebay.com/sch/i.html?_fro...es%29&_sacat=0. I also like the increasing range of mounting styles available allowing for placement options behind our increasingly cramped panels.

One other comment: If you use diodes* (of any type) you can run two batteries in parallel safely. The danger was always been that without diodes, and with two batteries at different voltage output levels, that one battery could cross-charge the other. This could potentially happen without any current limit (!) until they equalize voltages. On a single bus with two batteries and diodes, the battery with the greatest voltage level would power the bus by itself until the separate battery's voltages equalized.

- John OHM Ω

* Teaching Moment - A diode only allows current to flow in one direction. In our case current will be limited to flowing from the battery to our avionics. As current flows through a diode there is a small voltage drop across the input to the output. We want to avoid, or limit, this voltage drop in our glider based power systems as we have no generating power source as found in airplanes.

I like the ideal diodes, dislike the 0.3v drop across the Tyco breakers, run my batteries to one bus through low loss Schottky diodes.

I also believe that the number of angels on the head of the pin should be represented in Roman, not Arabic numbers in base 8.