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Old April 8th 20, 05:07 AM posted to rec.aviation.soaring
Andy Blackburn[_3_]
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Default Battery switching without tears

On Tuesday, April 7, 2020 at 8:58:53 PM UTC-7, 2G wrote:
On Tuesday, April 7, 2020 at 8:06:46 PM UTC-7, Andy Blackburn wrote:
I put a power resistor in the circuit to keep the current surge down. I undersized the capacitor so if I mess up on the with rotation I can lose power. Typically I'll shut off some non-essential equipment to lower the draw if I really don't want a computer reset.

Andy

On Sunday, April 5, 2020 at 8:45:30 AM UTC-7, jfitch wrote:

What is the inrush current when you first switch the power on? Must not be enough to blow the fuse, but that'd be something I'd want to O'scope with a current probe.


You didn't say what the resistor size was. There is already a resistor in the circuit - it is called the internal resistance of the battery,wiring resistance, switch contact resistance and the equivalent series resistance (ESR) of the capacitor.


I think it was only a few Ohms, but it was a big sucker so it could take the current. I figured bet to play it safe so you know where you are dissipating the energy. Probably unnecessary, but I am a belt + suspenders kind of guy.

Andy