How much of a performance hit will there be running CB off of a fuse block like this on a shared circuit vs wired directly to the battery?
How much of a performance hit is there running CB off of a fuse block?
- Thread starter toximus
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I run my CB power to my stereo amp under the steering column, fused of course. Amp runs direct to battery via 10 gauge cable.
I can't imagine a CB using enough power for this to be a concern but if you are worried just make sure the size of the wire feeding the block is sized to handle the max load the block is rated for. Based on your pic, you have a max of 80amps installed. An 8 gauge wire would handle up to 150amps with a distance of 4 feet.
http://www.offroaders.com/technical/12-volt-wiring-tech-gauge-to-amps/
http://www.offroaders.com/technical/12-volt-wiring-tech-gauge-to-amps/
You could install a stiffening capacitor in the system. The closer to the CB, the better.
You'd probably want to find something smaller, but here is a 62 farad capacitor designed for automotive use:
https://www.digikey.com/product-det...cs-division/XVM-16R2656-R/283-4464-ND/4879996
That capacitor is likely too large to be hooked in through the fuse block (charging it would draw several hundred amps or more), but a smaller one could suffice.
You'd probably want to find something smaller, but here is a 62 farad capacitor designed for automotive use:
https://www.digikey.com/product-det...cs-division/XVM-16R2656-R/283-4464-ND/4879996
That capacitor is likely too large to be hooked in through the fuse block (charging it would draw several hundred amps or more), but a smaller one could suffice.
Performance isn't the issue, electrical noise that can make it into your transmitted and received signals is the biggest potential issue. So it depends on where that fuse block is getting its power from. If there is something electrically noisy sharing that power source, like the fuel pump, alternator, etc. the CB would probably pick up that noise.
Which is why Basic- 2-Way Radio Installation 101 says 2-way radios should be powered from as close to the battery as possible. One good source of power is the 12v input lug on the firewall-end of the Power Distribution Center. The input lug is under a small black flap that lifts up to expose the lug.
This is mine, I have my two 2-way radios and a small aux fuse panel connected to it. Both this point and the battery are two very quiet (electrically speaking) attachment points, no filter capacitor is needed for either.
Which is why Basic- 2-Way Radio Installation 101 says 2-way radios should be powered from as close to the battery as possible. One good source of power is the 12v input lug on the firewall-end of the Power Distribution Center. The input lug is under a small black flap that lifts up to expose the lug.
This is mine, I have my two 2-way radios and a small aux fuse panel connected to it. Both this point and the battery are two very quiet (electrically speaking) attachment points, no filter capacitor is needed for either.
OP
I suppose I used the wrong word. I should have said noise finding it's way into the CB signal.
The fuse block will be fed directly from the battery with a 6 or 4ga line with a large fuse right off the battery. But there will be heated seats, led lights, stereo amps, etc connected to that fuse block also.
@Jerry Bransford based on your example, it sounds like my proposed connection is about the same as yours in terms of other items being on the same wire? So I should be fine?
The fuse block will be fed directly from the battery with a 6 or 4ga line with a large fuse right off the battery. But there will be heated seats, led lights, stereo amps, etc connected to that fuse block also.
@Jerry Bransford based on your example, it sounds like my proposed connection is about the same as yours in terms of other items being on the same wire? So I should be fine?
OP
While everybody is here, how much can I ground through the dash? Am I safe to ground an additional 200-250amps* on top of factory? (*calculated total of the fuses, so actual load may be lower since it's unlikely everything will be on at once)
Or should I be using a bus bar with a ground directly to the battery?
Or should I be using a bus bar with a ground directly to the battery?
OP
I just thought about this. If grounding this much through the dash is a concern, I can run a grounding cable between the battery and the dash. No bus bar required.
I taped into the cigar lighter/accessory port fuse in the behind-the-glovebox fuse panel to power my CB. It was thought of as a temporary measure but I have not changed it yet. Works fine but at soon as I turn on my LED fog lights the CB becomes unusable on all ch due to constant static.
You will need to add a grounding strap to the battery at the minimum if you're using a lot of current. In my Jeep, I used a 1 foot section of 2 AWG cable straight to the radiator support bolt.
It is the yellow wire in the below photos.
Amperage testing proved that the new strap is a far better ground than the stock one. Notice that 80% of the current is flowing through the new yellow wire, not the stock one. This not only improves the efficiency of the system, it also reduces noise due to grounding issues. For larger systems, it even reduces the fire hazard due to the stock strap becoming overloaded.
It is the yellow wire in the below photos.
Amperage testing proved that the new strap is a far better ground than the stock one. Notice that 80% of the current is flowing through the new yellow wire, not the stock one. This not only improves the efficiency of the system, it also reduces noise due to grounding issues. For larger systems, it even reduces the fire hazard due to the stock strap becoming overloaded.
FWIW I installed my CB on a shared circuit and had a terrible amount of accessory whine. I ended up getting a ring terminal from Autozone that fits under the positive terminal clamp to attach a spade. Worked like a charm.
OP
I wonder how much of that is due to the factory battery clamps on your 05-06.
The LED's connected to your fuse block may create electrical noise in your CB.
My simple fuse block powers radio communications and my Viair compressor which is never used at the same time as any radio Tx and almost never during Rx thus not a source of electrical noise. The third fuse is the circuit for temporary 12v accessories also seldom if ever used at the same time as my CB or ham radio. (This last circuit does double duty as the input to the battery from my Battery Tender used when the jeep sits idle.)
I experimented with LED lights plugged into the temporary circuit. They wreaked havoc on my CB, hence my suggestion that your comms be wired independently of any wiring connected to LED's.
My simple fuse block powers radio communications and my Viair compressor which is never used at the same time as any radio Tx and almost never during Rx thus not a source of electrical noise. The third fuse is the circuit for temporary 12v accessories also seldom if ever used at the same time as my CB or ham radio. (This last circuit does double duty as the input to the battery from my Battery Tender used when the jeep sits idle.)
I experimented with LED lights plugged into the temporary circuit. They wreaked havoc on my CB, hence my suggestion that your comms be wired independently of any wiring connected to LED's.
OP
That's probably part of it. The other part is probably where the wire terminates hasn't been cleaned up in 13 years. The stock wire is significantly smaller AWG and longer, which will have a significant effect on how much current flows through it.
OP
I have mine ran straight to my battery, inline fuse, when I turn my AC fan on it makes horrible noises through my CB. Lol
My Jeep makes terrible RF noise at CB frequencies. Just use a 12V jumper battery or a friends car and jumper cables to power your CB if you suspect power noise. If your problem doesn't go away then power supply isn't your problem. I would strongly suggest not wasting a single minute re-wiring a CB without doing this simple test, it is in my opinion a big waste of time.