Is 12gauge power-wire and 20 Amp fuse Overkill for a Stryker SR955HPC?

[wingclip]

Hi Folks,
I have a Stryker SR955HPC (V2) radio that's been converted to 11 meter and has been Peaked & Tuned. I don't have a 'kicker' (I don't know if they say that anymore but when I was an OTR/48 driver, that meant a power amp to boost the output), and I don't intend to get one.

Right now, the SR955 transmits about 20 to 25 miles w/o skip. I've checked the transmit power with 3 different meters and they all say the PEP is about 70W to 80W. However, I can see when I transmit, the voltage drops from the 14.4V (not transmitting), to 13.3v-13.4v!

I have it installed in a 2022 Jeep Grand Cherokee WK and at this time. I plan to change the present power lines to a 12-gauge wire and run it directly to the Jeep's battery, (which is under the front passenger seat). The radio is presently powered by a 16-Gauge 3-pin wire, plugged into a cigarette lighter port. The 16-Gauge power wire has a single15 Amp bus fuse in-line on the positive side.

It took quite a lot of searching before I found a 3-Pin power cable in the 12-Gauge size. I found this one, (linked): "3 pin POWER CORD Extra HEAVY Duty 12 Ga for CB / Ham radios - Workman CB3AXX". The Workman CB3AXX has 2 inline fuses. The positive line has a 10-amp fuse and the negative line has a 4-amp fuse.

OK, so because it was hard to find any 12-gauge, 3-pin, power wires for CBs, I began wondering if there was a reason for that. It seems to me that the heavier gauge wire would be a step up from the 16 gauge, but am I missing something? Should I avoid the 12-gauge wire for a direct connection?

Also, the Workman's CBAXX has a fuse in each line, but neither is 15 amps. I thought I should maybe replace the 10-amp fuse in the positive line of the CBAXX for a 20-amp fuse. Would that be a generally good idea?

And what about the 4-amp fuse they supply in the negative line? I didn't plan to change that fuse, but then, I'm not so sure what I should do with it. Does anyone think I should remove or change the 4-amp to something else?
My thanks to anyone who may help me decide.
Rich

 

[mmckenna]

Hi Folks,
I have a Stryker SR955HPC (V2) radio that's been converted to 11 meter and has been Peaked & Tuned. I don't have a 'kicker' (I don't know if they say that anymore but when I was an OTR/48 driver, that meant a power amp to boost the output), and I don't intend to get one.

Right now, the SR955 transmits about 20 to 25 miles w/o skip. I've checked the transmit power with 3 different meters and they all say the PEP is about 70W to 80W. However, I can see when I transmit, the voltage drops from the 14.4V (not transmitting), to 13.3v-13.4v!

I have it installed in a 2022 Jeep Grand Cherokee WK and at this time. I plan to change the present power lines to a 12-gauge wire and run it directly to the Jeep's battery, (which is under the front passenger seat). The radio is presently powered by a 16-Gauge 3-pin wire, plugged into a cigarette lighter port. The 16-Gauge power wire has a single15 Amp bus fuse in-line on the positive side.

Cigarette lighter plugs are poor performers. It relies on springs to keep the contacts touching. Seeing a voltage drop like that isn't surprising.
Other issue, those lighter plugs are usually only rated for 10-20 amps, which might be OK for your radio, but isn't ideal.
Also, the power for the plug is often bundled in with a lot of other wiring under the dash, and that can often be a source of noise.

Getting away from the cigarette lighter plug will do you a lot of good.

It took quite a lot of searching before I found a 3-Pin power cable in the 12-Gauge size. I found this one, (linked): "3 pin POWER CORD Extra HEAVY Duty 12 Ga for CB / Ham radios - Workman CB3AXX". The Workman CB3AXX has 2 inline fuses. The positive line has a 10-amp fuse and the negative line has a 4-amp fuse.

I think you'll find that the 4 amp fuse is actually on the yellow wire, which is usually connected to an unswitched power feed to keep the memory alive.

The negative lead should either NOT be fused, or at least have a fuse the same size as the red primary power side.

OK, so because it was hard to find any 12-gauge, 3-pin, power wires for CBs, I began wondering if there was a reason for that. It seems to me that the heavier gauge wire would be a step up from the 16 gauge, but am I missing something? Should I avoid the 12-gauge wire for a direct connection?

Also, the Workman's CBAXX has a fuse in each line, but neither is 15 amps. I thought I should maybe replace the 10-amp fuse in the positive line of the CBAXX for a 20-amp fuse. Would that be a generally good idea?

Fuses are a safety device and should not be increased in value unless the -entire- circuit is appropriately sized. Simply increasing the fuse size can result in overcurrent that -may- result in the wiring overheating, fire, damage, etc.

And what about the 4-amp fuse they supply in the negative line? I didn't plan to change that fuse, but then, I'm not so sure what I should do with it. Does anyone think I should remove or change the 4-amp to something else?
My thanks to anyone who may help me decide.
Rich

Double check that it is actually on the black (-) wire. 4 amp fuse on the negative lead with a 15 amp on the positive side isn't going to work out very well….


Here's what I'd suggest:

A "CB" running 70 watts is probably going to be happy with a good circuit fused for 20 amps. Best way to do that is to get some 10 gauge wire. Run a short piece of 10 gauge from the battery positive terminal to a fuse block/breaker as close to the battery as you can safely make it. Reason for that is you want that fuse to protect the entire circuit.
Run the rest of the 10 gauge from that fuse/breaker to the radio positive.

The larger gauge wire will give you plenty of capacity and reduce voltage drop.
12 gauge might be fine if the run is really short, but if you are going to put all this work into it, do it right the first time.

As for the negative, DO NOT run that all the way back to the battery. Modern vehicles have a load sensor on the negative battery post to chassis lead. Running the radio back to the negative terminal will bypass that and can cause some headaches.
Instead, run a SHORT piece of 10 gauge from the radio negative connection to a grounding point on the chassis or under the dashboard. Keep that run as short as possible. This gives you two things: It lets the battery load sensor do its job. It also gives your radio and good short path to ground, which can help with noise and other issues.

 

[wingclip]

Thank you Mmckenna! In fact, I think I have read a that info a few days ago in a similar reply to someone else with a power line question, and it was probably yours. That's why I decided to go with a direct power wire.

I could only go by the CBAXX ad and picture in the Amazon about the 4 and 10 amp fuses because I haven't got the item yet. It's due to be here tomorrow.

If you click on that link I supplied, you'd see that it's only 2 wires and they clearly say the 4 amp fuse is in the negative line, (the 10 amp is in the positive).

The CBAXX wires are only 6 feet long but because the Jeep's battery is under the passenger seat, I only need about 3 or 4 feet to reach the radio, (closer to 3 feet than 4), so based on what you said, 12 gauge should be OK.

I'd gladly go with 10 gauge or even 8 gauge but I can't find a 3-pin power plug with 10 gauge wire. Hell, just before I found that CBAXX wire, I almost gave up trying to find one with 12-gauge wire!

As for connecting to ground, I read your other posts and I certainly will connect the ground to the metallic part of the Jeep and not a direct connection to the negative of the battery.

That leaves just one concern; I can replace the CBAXX's 10 amp, inline, fuse on the positive wire with a 20 amp fuse, no problem. And, I'll cut the wire so that the fuse is close to the battery.

But I'm thinking that I should probably do away with that 4 amp fuse altogether, no? I mean, why would I want that fuse in there in the first place?
Thanks for the fast reply!
Rich

 

[mmckenna]

Thank you Mmckenna! In fact, I think I have read a that info a few days ago in a similar reply to someone else with a power line question, and it was probably yours. That's why I decided to go with a direct power wire.

I could only go by the CBAXX add and picture in the Amazon about the 4 and 10 amp fuses because I haven't got the item yet. It's due to be here tomorrow.

If you click on that link I supplied, you'd see that it's only 2 wires and they clearly say the 4 amp fuse is in the negative line, (the 10 amp is in the positive).

I would not buy from a vendor that sells something like that. The amount of current carried on the positive and negative conductors is going to be the same. If you have a 10 amp on the positive lead and a 4 amp on the negative lead, and the radio draws more than 4 amps. the fuse on the negative side is going to blow.

If some of the return current is carried through the antenna mount or the chassis mount, then you have other issues.

Red flag.

The CBAXX wires are only 6 feet long but because the Jeep's battery is under the passenger seat, I only need about 3 or 4 feet to reach the radio, (closer to 3 feet than 4), so based on what you said, 12 gauge should be OK.

Should be fine. My only concern is with the "Peak and Tune". That will make it pull more than the original design/alignment. Might be fine.

I'd gladly go with 10 gauge or even 8 gauge but I can't find a 3-pin power plug with 10 gauge wire. Hell, just before I found that CBAXX wire, I almost gave up trying to find one with 12-gauge wire!

The goal is to run the larger wire most of the way, and then connect the smaller right at the radio. Less voltage drop.
But, based on what you are saying, I think you'll be fine with the 12 gauge.

As for connecting to ground, I read your other posts and I certainly will connect the ground to the metallic part of the Jeep and not a direct connection to the negative of the battery.

That leaves just one concern; I can replace the CBAXX's 10 amp, inline, fuse on the positive wire with a 20 amp fuse, no problem. And, I'll cut the wire so that the fuse is close to the battery.

But I'm thinking that I should probably do away with that 4 amp fuse altogether, no? I mean, why would I want that fuse in there in the first place?
Thanks for the fast reply!
Rich

The 4 amp fuse, if it really is on the negative lead, is a major red flag.

As long as you have a short run, and the conductor is 12 gauge, a 20 amp fuse ~should~ be fine. My only concern would be the quality of the wire, connectors, fuse socket, etc. Sometimes the Chinese stuff gets a bit fast and loose with the specifications, and they really don't care since all they want is your money.

 

[wingclip]

CORRECTION UPDATE: I've been calling that Workman item a "CBAXX". However, I just realized that I should have been typing it as "CB3AXX". Otherwise, everything else I wrote about it is correct and from the ad.

 

[wingclip]

Thanks Mmckenna! Based on what you've said, I have to guess that you can't click on the link for that CB3AXX ad that I supplied. If you could, you'd see that it's a "Workman" product. They've been around a mighty long time.

The ad is from Amazon and yes, I assure you that there's only 2 wires and the ad states that the fuses are in-line; the hot wire is 10 amp and the negative is 4-amp. However, I agree about those little, white plastic, inline fuse cases for the glass bus-fuse. I'm going with a 20 amp Blade fuse rig that I already happen to have.

You said: "My only concern is with the "Peak and Tune". That will make it pull more than the original design/alignment. Might be fine." It sounds like you may not be entirely comfortable with that setup. Do you suppose I should maybe consider a 30 or 40 amp fuse?

Anyway, I have to agree with you, the 4-amp to Neg and 10 amp to Pos doesn't make any sense. Replacing the 10 amp fuse with a 20 amp fuse was what I thought you suggested, but do you think I should go with an even higher amp fuse?

Also, I'm going to cut the wire on the negative line just above the 4-amp fuse and remove it. Like I said, the 2022 Jeep's battery is right under the passenger seat. That puts the Positive pole of the battery less than 16 inches from the back of the radio.

Still, I didn't know that I could get away with soldering a 10 gauge wire to a stubby end of the 12-gauge plug's wire! If I knew that, I would have bought the 10-gauge wire in the first place.

I've got all kinds of shrink tubing and soldering experience and it wouldn't take any time for me to do it.

So, now that I already have the 12-gauge power wire on its way here, I'll probably go ahead and use it as planned. But if I still see more voltage drop than .3v, I'll yank it out and put together a 10-gauge (or maybe even an 8-gauge?), power wire with a fuse block.

You've been a bigger help than you may think!
Thanks a lot!

 

[mmckenna]

Thanks Mmckenna! Based on what you've said, I have to guess that you can't click on the link for that CB3AXX ad that I supplied. If you could, you'd see that it's a "Workman" product. They've been around a mighty long time.

No, I know who they are, and I looked it up. Amazon, Walcotts, a few others and Workman's own website all show the same thing.

I think it's probably a typo and they all just keep cutting and pasting the same thing over and over again.

DC power doesn't work that way. The 4 amp fuse will blow when exceeding 4 amps. The 10 amp will blow when exceeding 10 amps. Having a 4 amp fuse and a 10 amp fuse on the same circuit is pointless as the circuit will open at 4 amps, and why I expect it's just a typo. No one who's been doing this stuff for a while would set up a circuit like that.

The ad is from Amazon and yes, I assure you that there's only 2 wires and the ad states that the fuses are in-line; the hot wire is 10 amp and the negative is 4-amp. However, I agree about those little, white plastic, inline fuse cases for the glass bus-fuse. I'm going with a 20 amp Blade fuse rig that I already happen to have.

OK. As long as the circuit is sized to carry 20 amps, a 20 amp fuse is fine.

You said: "My only concern is with the "Peak and Tune". That will make it pull more than the original design/alignment. Might be fine." It sounds like you may not be entirely comfortable with that setup. Do you suppose I should maybe consider a 30 or 40 amp fuse?

No. If it was me what I would do is bench the radio, hook it up to a power supply and a ammeter and see what the thing actually draws at fully power/modulation. Then multiply that by 1.2. That's the minimum size of the wiring/fuse that you should use.

Some peak/tune jobs are done by guys that know exactly what they are doing. Some are done by guys (often called "Golden Screwdrivers" that watch a few YouTube videos, start twisting slugs, messing with coils and simply look at the power output.
Truth is, you need to look at not only the power output, but also the current consumption of the radio, spectral purity, if the power is on the frequency or splattering all over the band.

If you trust the Peak/Tune shop and the radio seems to be working right, 20 amps should be fine for a radio putting out 70 watts.

Anyway, I have to agree with you, the 4-amp to Neg and 10 amp to Pos doesn't make any sense. Replacing the 10 amp fuse with a 20 amp fuse was what I thought you suggested, but do you think I should go with an even higher amp fuse?

Also, I'm going to cut the wire on the negative line just above the 4-amp fuse and remove it. Like I said, the 2022 Jeep's battery is right under the passenger seat. That puts the Positive pole of the battery less than 16 inches from the back of the radio.

Still, I didn't know that I could get away with soldering a 10 gauge wire to a stubby end of the 12-gauge plug's wire! If I knew that, I would have bought the 10-gauge wire in the first place.

I've got all kinds of shrink tubing and soldering experience and it wouldn't take any time for me to do it.

So, now that I already have the 12-gauge power wire on its way here, I'll probably go ahead and use it as planned. But if I still see more voltage drop than .3v, I'll yank it out and put together a 10-gauge (or maybe even an 8-gauge?), power wire with a fuse block.

You've been a bigger help than you may think!
Thanks a lot!

I think you'll be fine. 70 watt radio, 20 amp circuit, short power lead, should work just fine.

 

[wingclip]

Thank you Sir! I have to agree about the ad's Picture and the type-O because, as stated many times, it just doesn't make sense. However, I may post an update tomorrow night when I get the wires. If it really does have two fuses (and they're rated as said in the ad), I'll even post a picture, LOL.
Thanks again,
Rich

 

[wingclip]

UPDATE:
Well, as I promised, I have included a picture of the Workman CB-3AXX power wire. It was late getting here, (I expected it Tuesday), but it got here.

Incredibly, the ad was accurate!! No type-O's or distorted duplicate images. They REALLY did place a 4-Amp fuse in the negative line and a 10-Amp fuse in the positive line!!

That makes no sense at all to me, but I confirmed it by checking each fuse with a magnifying glass so I could be sure I wasn't misreading the ratings. Please see Picture:

 

[merlin]

A couple pointers from my installs.
You are best with 12 ga wire and 60 watt PEP, at least a 20 amp fuse in the positive side.
Negative you can run shorter to a good negative ground. (no fuse)
Positive is best run straight to the battery with the fuse near the battery.
My mobiles were a Kenwood TS440 and Barrett 550, both 100 watt PEP
Fuse block was 30 amp to both radios. A Hustler antenna with ham coils for the Kenwood
and a Wilson 1000M to the Barrett that was a 10/11 meter setup. (mostly CB)
Neither radio peaked over 25 amp, so the 30 amp was a little overkill.

 

[prcguy]

UPDATE:
Well, as I promised, I have included a picture of the Workman CB-3AXX power wire. It was late getting here, (I expected it Tuesday), but it got here.

Incredibly, the ad was accurate!! No type-O's or distorted duplicate images. They REALLY did place a 4-Amp fuse in the negative line and a 10-Amp fuse in the positive line!!

That makes no sense at all to me, but I confirmed it by checking each fuse with a magnifying glass so I could be sure I wasn't misreading the ratings. Please see Picture:
View attachment 141316

In many installations the antenna and/or radio is grounded and the ground current will divide between the antenna path and the black wire with fuse. If the radio is floating with a mag mount antenna a 60w radio should make the fuse go off like a flash bulb.

 

[mmckenna]

Wow, I guess they are relying on no one using this on more than a bone stock CB, or that they'll have the chassis and/or antenna well grounded.

Gotta wonder what they are thinking with that.

 

[mmckenna]

Having a 4 amp fuse and a 10 amp fuse on the same circuit is pointless as the circuit will open at 4 amps, and why I expect it's just a typo. No one who's been doing this stuff for a while would set up a circuit like that.

UPDATE:
...
Incredibly, the ad was accurate!! No type-O's or distorted duplicate images. They REALLY did place a 4-Amp fuse in the negative line and a 10-Amp fuse in the positive line!!

Wow, gotta wonder about these guys.
I guess Workman is what I always thought they were, a front company reselling Chinese parts. There's zero reason to sell a power harness like that, unless they are secretly in the fuse business also.

I wonder how many CB radio operators this has completely confused?

 

[wingclip]

Thanks to all!
@ Mmckenna: "I wonder how many CB radio operators this has completely confused?"

Seriously, I feel like no one even needs to know specifically about radios. I think anyone who knows even a little about why a fuse is there in the first place would know that this 4A/10A setup is just not right.

As you and others have said, the 4Amp fuse would trip long before the 10A would, which makes the 10A good for nothing at all. To me, that seems obvious, but maybe some don't know that, (...I don't know...)

In addition to the double fuses, Workman placed them within 10 inches of the plug, making it impossible to connect the wire with the fuse as close to the battery as I intend to do.

I'm simply going to cut the wires just above the fuse holders and then reattach the fuse-less 12 gauge wires, (or, maybe even 8 gauge).

Then I'll attach a 20A fuse to the positive wires and it'll be within 3" of the "+" battery post. I'll run the negative wire to a grounding point on the chassis or body, (or both). It won't be the perfect ground but it'll be a lot better than my cigarette lighter connection.

The Stryker SR A-10 Mag-mount has a good ground plain and for that 2022 Jeep GC, it couldn't be in a better position.

BTW, I just didn't like the SWR/Power meters I had so I bought a Diamond Antenna SX-200, (won in an auction), and it gave me a much better, (clearly shown), reading of the Average and Peak power of the SR955HPC. In fact, the radio is putting 55W to 63W, NOT 70 to 85.

The 55/60W was what CB Shop tech, ("Tiny's CB & Ham" in Oregon), said he had brought it to.
My thanks to "Merlin" & "PCRGuy" too!
Rich

 

[mmckenna]

Thanks to all!
@ Mmckenna: "I wonder how many CB radio operators this has completely confused?"

Happy to help. I'm kind of waiting for someone to pop up on this thread and claim that they have been running their super peaked/tuned gonzo CB/10 meter/11 meter super station radio on this wire for "years and never had a problem".

In addition to the double fuses, Workman placed them within 10 inches of the plug, making it impossible to connect the wire with the fuse as close to the battery as I intend to do.

This is why I usually make my own cables.
Most LMR companies will either include really long power cables, or at least sell them as an option. Motorola includes the fuse holder as a separate item (or at least they did last time I bought their stuff). Upfitter shops will run a larger gauge wire with breaker from the battery, then distribute with a fused distribution block at the radios.

BTW, I just didn't like the SWR/Power meters I had so I bought a Diamond Antenna SX-200, (won in an auction), and it gave me a much better, (clearly shown), reading of the Average and Peak power of the SR955HPC. In fact, the radio is putting 55W to 63W, NOT 70 to 85.

The Workman stuff kind of looks like the low tier meters that MFJ sells on their amateur radio product line. Not great stuff, but "good enough" for those getting started. The Diamond should be a good meter. Those are pretty popular in the ham community and have a good reputation.

The 55/60W was what CB Shop tech, ("Tiny's CB & Ham" in Oregon), said he had brought it to.
My thanks to "Merlin" & "PCRGuy" too!
Rich

Would be interesting to see what your meter shows.

 

[wingclip]

"I'm kind of waiting for someone to pop up on this thread and claim that they have been running their super peaked/tuned gonzo CB/10 meter/11 meter super station radio on this wire for "years and never had a problem"."

"Would be interesting to see what your meter shows.": Yes, when I got the Diamond SX-200 on Tuesday, I tested the radio and it confirmed the CB Shop's stats; about 55Watts.

The Dosy TC4002-PSW was the worst of the meters I used (and the most expensive). I bought it new about 3 or 4 weeks ago and all I can say is that it doesn't seem to be working right. (That's the one that I read the "70-85W" from).

My other two meters, (Asiatic and Workman), cost a lot less but I couldn't see the meters well enough to be sure. However they both worked better than that Dosy.

The Diamond was far easier to read and very smooth. The instructions were clear and the meter itself was well made and put together. I felt confident of what I was reading on that one.
Rich

 

[mmckenna]

Make sure you are testing into a true 50Ω load to get an accurate reading. If you are testing into your antenna, the power output readings will be flawed.


A good meter makes the difference. I started off with a cheap MFJ meter. It was good enough for tuning CB antennas.

 

[wingclip]

Make sure you are testing into a true 50Ω load to get an accurate reading. If you are testing into your antenna, the power output readings will be flawed.


A good meter makes the difference. I started off with a cheap MFJ meter. It was good enough for tuning CB antennas.

Ah Yes! I haven't bench tested the Radio with the Diamond meter but I did test it with the others, (and a 50Ohm dummy load). I plan to connect the dummy load and test again after I get the power wires properly connected to the battery.

In my opening post, I said that when the radio was connected to power via the cigarette lighter port, the output voltage dropped from 14.4V (in receive mode), to 13.3/13.4V when transmitting.

But in fact, I was going by my memory (which sometimes fails me). I checked it last night and the transmit power dropped to 12.3/12.7V from the receive mode voltage of 14.4V!! That's more than 2 volts lost in the wiring!

It was about two weeks ago when I had the radio in the house for bench tests and some software changes. I had my DC switching power connected to an Variac Transformer (to maintain 112VAC). The radio had a 50 Ohm dummy load. In the tests, the DC voltage input was 14.00V and the transmission voltage only dropped about .3-Volts.

I doubt that I can hope to expect see that when the radio is back in the Jeep (and after I rewire the power), but I certainly expect to see a big improvement, (at least a 1 to 1.5 Volt improved efficiency), with a drop no more than 1 volt.

Does anyone think that's too much to expect in a mobile powered connection?
Rich

 

[mmckenna]

Seeing that much voltage drop through a cigarette lighter plug/socket isn't really surprising. Some of it was probably undersized wire, some of it was probably poor connection with the cigarette lighter plug/socket. Those things rarely make good connections and the only thing I ever use mine for is charging my cell phone, which I rarely do in my truck.

Does anyone think that's too much to expect in a mobile powered connection?
Rich

With a 6 foot run of 12 gauge wire, 14.4 volts (engine running) and properly installed connectors, I would expect 0.5 volts loss, give or take.
That should be just fine, and you've already put way more effort into this than most do. The radio should run just fine down to a bit less than 12 volts. RF Power will likely drop off as voltage drops, but a few watts here and there won't make a difference in performance.

Your goal should be to make as few connections as possible in the power run to reduce voltage drop. Some cheap fuse holders can be pretty bad. Any crimp lugs should be the right size/type for the wire you are using, and crimped with a good crimper tool. Soldering not required.

Considering that many will happily use a cigarette lighter plug with undersized speaker wire, wire nuts, wires twisted together, bundles of excess wire, you are w-a-y out in front of most.

 

[wingclip]

Outstanding! Thank you very much!
Rich