[the roadie]

1) Using the main cig lighter wiring is a bad idea for one very subtle reason. Blowing that fuse also disables the OBDII power feed, so that if you need your Service Engine Soon codes read, the plug in scanners will barf and not light up. Using an aux cig lighter is advisable for small radios.

2) The main radio power feed is permanent 12V, not switched by the accessory position of the ignition switch. There are actually few circuits fed directly by the ignition switch, which is a high failure rate item anyway.

3) I would recommend a relay fed by the battery (or the megafuse terminal up front) and controlled by accessory or run signals. I've posted these before, but I can trace a few if you want to use an add-a-fuse to snag a control signal. Unless you always remember to turn off the radios and don't need a relay.

 

[the roadie]

You are the one who says you should never pull anything off the mega fuse?

Don't remember that. I remember posting that you CAN steal 50-60 amps off the rear fuse block without worrying because the megafuse DOESN'T feed every fuse in there. I wired my rear seat deep discharge battery this way, and it draws 40-45 Amps when discharged.

But in this case I should have been more precise - "a relay fed by the battery (or the megafuse terminal up front that's fed by the battery)..."

 

[the roadie]

yeah Coyote.. watts and amps are totally different things.. :yes:

He's my ankle-biter ..... I mean protege ..... we've talked. :coffee

 

[the roadie]

Running a capacitor is silly idea.

Coyote isn't running one. He just said he heard it discussed in the amateur radio community and wanted to make sure we had heard of that. I've also PMed him the proper equation, which is:

I = C * dv/dt

and why caps might work in an audio application but not in a radio transmitter install.

It seems they don't teach this stuff in high school physics anymore, or else the subject gets skipped over.