[aprssig] 12V wiring ideas

KBØNLY kb0nly at mchsi.com
Sat Oct 29 12:39:41 CDT 2011

It is silly to fuse ground, quite stupid really, because you shouldn't be 
connecting an accessory directly to the battery for its ground connection.

Use the industry standard for installing two way radio equipment.  The 
negative always goes to body/frame NOT to the battery.  No fuse necessary 
and less chances of trouble.  It doesn't make it any better going to the 
battery for a ground, all you do is add a loop.

The radio if mounted to metal is grounded through its body to the vehicle 
body, also through the shield of the coax.  So if you ground the radio's 
power lead to the battery the radio and antenna mount now become a second 
path for the vehicles electronics if the factory battery cable would fail or 
become faulty with a high resistance connection at the engine block or body, 
they usually ground to the block with a heavy cable and a smaller gauge 
cable to the body near the battery.  I always ground all radio equipment at 
its install location.

Why?  If the vehicles ground cables fail everything loses power, radios 
included.  The radio's do not become a ground source for the rest of the 
vehicle.  Which is why you have to put a fuse in if you take the stupid 
route and install the ground on the battery terminal.

I spend so much time fixing radio installs, both commercial and amateur, and 
I can tell you its better to ground to the body/frame.  I have also fixed 
noise problems on many ham radio mobile installs by moving the ground.



-----Original Message----- y
From: D
Sent: Saturday, October 29, 2011 12:12 PM
To: TAPR APRS Mailing List
Subject: Re: [aprssig] 12V wiring ideas

I had specified 10a in power and ground.  The guy argued that too. He 
thought it was silly to fuse ground.

Rudy Benner <rudy at ve3bdr.com> wrote:

>I would recommend crimp and solder. Don’t forget the fusing. Do it right.
>From: david vanhorn
>Sent: Saturday, October 29, 2011 10:46 AM
>To: TAPR APRS Mailing List
>Subject: Re: [aprssig] 12V wiring ideas
>Just for laughs, I stopped by a car install place here, and asked them for 
>a quote on running the battery power with hot and gnd from the battery, on 
>#8 into the passenger compartment.  He tries to argue that he can pick up 
>hot and ground under the dash, but I insist that I want it done this way.. 
>They quote $100 for labor and 3 hours to do the job, then the guy tells me 
>that he'll just double up #16 wire.  (!!!)  If I want real #8, I had to buy 
>two amp kits for another $130.
>They said it's too expensive to stock wire by the foot.   (for WHO?)
>I shudder to think what the job would have looked like.
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