Wiring power AND ground for GMRS and CB radios direct to battery?

MiamiC70

Active member
Wiring Power AND ground for GMRS and CB radios direct to battery?
I’ve always powered comms direct to battery on Jeep and Discovery and that’s what I was going to do with my 2019 Subaru Outback. However, there is a lot of confusing and conflicting information online as to what is best practices in wiring ground. One says wire direct to battery negative terminal the other says wire it to the battery negative grounding point on car. I am wiring up using one of these.


The reason for avoiding battery post ground is apparently new cars have battery monitoring systems that “could” cause issues or interference. New to me..

Thoughts?
 

Verkstad

Raggarkung
Provided not trying to avoid or include a current monitoring device somewhere in the negative path, I dont think it makes much difference.
For the most part, I like to minimise adding clutter on battery posts, I would connect the new negative at the same place the negative battery conductor bolts to the chassis.
Said that, were it a winch or similar high current load, I would connect direct to battery post.
One says wire direct to battery negative terminal the other says wire it to the battery negative grounding point on car. I am wiring up using one of these.
 

Billoftt

Active member
I would consult your vehicle's owner's manual and see what IT says. On my Xterra it states:

"When installing a CB, ham radio or car phone in
your vehicle, be sure to observe the following
precautions; otherwise, the new equipment may
adversely affect the engine control system and
other electronic parts."

"Do not ground electrical accessories directly
to the battery terminal. Doing so
will bypass the variable voltage control
system and the vehicle battery may not
charge completely. Refer to “Variable
voltage control system” in the “Maintenance
and do-it-yourself” section later
in this manual."

Thus, I install the negative to the grounding point the battery goes to, vice directly to the negative terminal.
 

Robert Bills

Explorer
I wired the communications in my Xterra exactly as @Billoftt for exactly the same reason.

I do not have a similar "variable voltage control system" in my Jeep and wire directly to the battery terminals using a Blue Sea #5024 battery terminal fuse block.

Blue Sea Fuse Block.jpg


That being said, the current draw of the typical CB or mobile ham is so small that I doubt that wiring comms directly to the battery terminals would cause a problem even with a "variable voltage control system."
 
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