Aftermarket stereo installation question...

[Bocephus]

Got a question for some of you electrical guru's. So I installed an aftermarket stereo in my Humvee (couple of amps, and a head unit and some speakers). I have some pretty healthy noise coming through the speakers when no volume is being sent them. My gut reaction to this in any other scenario is a grounding issue, and that is my thoughts here.

My question is, should I ground to the battery, or actual frame? I currently have the amps mounted under the rear passenger seat, and them wired to a single battery and the runs are only 2.5 feet or so.

I didn't know if because this was a 24v system, even though I'm only tapping off of one battery, if that was causing the issue being grounded back to the battery. And if so, should I just go to the frame.

Hope that makes sense, thanks in advance.

-B

 

[Dock Rocker]

I would grab a ground off off the block on the rear driver. Just clean it well while you are there.

I would also put on a supplemental grounding harness while I was pulling wire. That will solve a few future problems and may solve this one.


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[911joeblow]

These trucks are electrically noisy. Grounds are key as Dock Rocker said above. Grounding the stereo equipment to the battery will help. Ultimately you might need a noise filter.

 

[rchalmers3]

Here is a explanation of the causes for noise and a diagnostic routine that you might find helpfull:

https://www.crutchfield.com/S-LhgfF...car/noise_suppressors_installation_guide.html

 

[spoonsc1]

Definitely add the ground harness. all components in a 12v voltage system like you have need to be grounded to the chassis and NOT straight to the negative battery terminal.

also place a 12v system fuse/CB/disconnect at the battery to disconnect first, before pulling the ground off the batteries. as mentioned above, these things have horrible grounding and corrosion issues, so if a 12 volt stereo or CB is grounded straight to the battery, the antenna also being grounded to the chassis which may be the best path for the return of a 24v component, which burns up the 12v stereo/CB the minute you plug in the antenna. (solved this issue in the past for a builder)

the 12v fuse/circuit breaker/disconnect should be open first before disconnecting the battery ground and last after reconnecting. (if left connected, the power for the 12v is physically connected to the negative of the "second" or "24v" battery, this is just precautionary as it may still cause damage to the 12v components (similar to connecting the polarity backwards)

Ive been running a touchscreen stereo, rough country lights, CB, FLIR camera and back up camera and monitor(all antennas properly mounted using the ground plane of the HMMWV) off of the battery with a 100 amp cooper bussman battery equalizer without problems for a while now.

also, FYI cheap LED drivers in headlights etc will cause horrible RF interference

 

[Bocephus]

Appreciate the reply fellas.

As an electrical newbie..... spoonsc1 - when you say add an electrical ground harness, is that component that can be purchased, or is that simply adding a ground wire to the actual steel frame of the Humvee?

This is the second Stereo system I have installed in a Humvee, both times I connected straight to just the negative side of a battery. The first system had a little noise too, but since it was primarily built for hunting, I didn't care. That system has been working for about 2 years now with no problem (when I say system I'm referring to amps, subs, speakers, head unit).

But with this second system build, after spending about $3k on all the components, I don't want any speaker noise, hence why I'm trying to solve that issue.

And I did learn what you are talking about with cheap LED lights. This build I'm running front and rear cameras to an LCD screen, and when I turn on the rear LED light pods, it will make my cameras fuzzy.

 

[Action]

do low frequencies from the subs attract deer?

 

[Bocephus]

Only the big ones.

 

[spoonsc1]

Ground harness, can be locally made or purchased from a vendor. I believe there is a sticky or great info about it on here somewhere.

One of the reasons for not going to the battery post (-) is the shunt. basically a resistor, but bypassing the shunt by going to the battery terminal, this basically gives a better path through that wire than that of the shunt to the chassis add bad chassis grounds and it gets more likely a better path. naturally no two vehicles are the same, some never have a problem, some blow up 2 stereos before deciding to not install an antenna and just isolate it from the chassis and deal with crap reception.

One more thing is stereo installation practices. usually you isolate the RCA cables from the power cables (usually in the trunks, RCA low voltage signal down one side of the car, power down the other). how it affects the amps being right there in with the batteries I cant imagine what can happen. in industrial networks and even low voltage with high voltage wire you make sure you cross the higher voltage wire at 90 degree to avoid noise or inducing a voltage into the low voltage or network wires(even with shielded cables).

 

[Bocephus]

Great info spoon, I appreciate it. I will look for some of those threads and read more on it. I haven't installed an antenna on any of my builds so far, so that's probably why I haven't fried a head unit like you are talking about.

 

[Bocephus]

Just ordered the grounding kit from Kascar, so I will get that installed.

 

[spoonsc1]

Just ordered the grounding kit from Kascar, so I will get that installed.

same place I got mine a while back. Great bunch of guys there, glad I have them right up the road!!