Battery switching without tears

On Monday, April 6, 2020 at 11:33:37 AM UTC-4, Tango Eight wrote:
Switches are generally rated according to interrupt capacity, and that's why the AC and DC ratings are different. In the immortal words of a friend of mine in the business, "DC just doesn't switch worth a ****". As the contacts open, an arc is struck. With AC current, the arc self extinguishes (for small switches) when the current goes to zero. The arc persists longer with DC, causes more contact wear, hence a reduced rating.

A "1A DC" switch is not going to fail or in any way be stressed by keying the mic and momentarily running 2, or even three or four amps. Try not to turn off the master while you are talking on the radio :-).

My panel has a CN2, CNv, radio, flarm. I have the standard issue Schleicher rotary switch, no modifications. Switching between batteries is simple: turn the knob. No drama, no instrument problems.

Evan Ludeman

Case in point to illustrate Evan's statement: I've tried to use a small water heating tank to use excess solar power to heat some water. Its heating element is rated 120VAC 15A. It has a thermostat with an internal switch to match. I fed it about 50VDC 6A from solar panels. That switch died in short order. Also note that we're warned not to disconnect solar panel connectors while the sun is shining and the power is being used, because the arc will damage the contacts in those connectors.