Battery switching without tears

On Sat, 04 Apr 2020 18:23:41 -0700, 2G wrote:

On one of my flights last year I had to switch between my avionics
battery and engine battery when the avionics battery voltage dropped too
low (I had left the master on after the last flight and could only
partially charge the avionics battery before launching).

Some years back I had a momentary disconnection problem with the XLR plug
supplying power to my panel: it carries a common ground plus a positive
line from each of the two batteries I carry - one supplies flight
instruments, the other drives radio and T&B.

I added small capacitors (18mm diameter x 35mm long, 35-50v, so 1000-2000
uF capacity or thereabouts for each capacitor - thats a guestimate since
I can't read their markings without major surgery), one for each battery,
and with a 0.1 ohm resistor in series with it.

This solved the problem completely, but my current draw is lower than the
yours: 500 mA for flight instruments and 200 mA with T&B running and
radio on and receiving.


--
Martin | martin at
Gregorie | gregorie dot org