24V Stereo & 12V Ham Install (1 Viewer)

[blastronaught]

Thought I would share my process for installing a 24V head unit and a separate 12V system to power a ham radio. I previously spent quite a bit of time getting acquainted with the condition of my power supply behind the dash. Discovered I had a 12V converter powering the old stereo (which has never worked since my ownership began last year), however the 12V output ranged 1-12V consistently, seemingly busted. See: 24V Radio Troubleshooting - https://forum.ih8mud.com/threads/24v-radio-troubleshooting.1313933/

New plan is installing a 24V stereo, and wiring a 24V-12V converter. Switch in place before the converter to avoid parasitic loss and so I can run the ham without the ignition on. No other 12V plans, but I'm going to put in a fuse box for future use, whatever that may be. Here is my plan for that, based on estimates of wire runs necessary; dotted lines indicate chassis ground.

Hardware has been ordered:
Converter - Victron Energy Orion, 25A non isolated 24V-12V
Switch - I'm tired of crappy switches so splurged on an aircraft salvaged MS24523-22 (1TL1-2). Hopefully used doesn't equal tired out.
Ham - Kenwood TM-V71A, 12V/15A
Radio - Continental TR7423, 24V/10A
Voltmeter - I'm still on the fence about this one. This should be switched with the ignition, so that complication may make it not worth it to me.
Distribution fuse panel: TBD

Few questions off the hop:
1) the converter supplies an OUTPUT of 25A continuous and 35A peak. I don't see the amp rating for the 24V input, but is it fair to assume it can be half of the output at peak (or something like 15-20amp)?
2) Is it okay to ground everything at chassis, despite the different voltages?
3) The only firewall penetration I see is on the right side, oposite the battery. Are there any on the left side/battery side I can use to shorten the run?

 

[blastronaught]

On further thought/research, answered my own questions (mostly).

1) Convert all loads to Watts, way easier to work with. On batt side, using 15A (360W) and on output side using 30A (also 360W). Both sides of converter are equally protected, which is probably overkill. I'll have plenty to cover the continuous capability of 300W, and can handle most of the peak range but still will blow before hitting the absolute max of 420W.
2) Research indicates this is fine/commonplace.
3) Still need to look closer to see if I can find a better firewall penetration to snake the wire through, but planning for around 10' should cover worse case of going through the opposite side of the battery to get through it.

Updated schematic reflecting these decisions, and re-wiring the volt meter so it is only on when the converter is on (which makes sense) below. By golly, I think I'm ready to start buying the harness equipment.

 

[JDM Journeys]

Just some feedback on the Vic dc->DC converters. I'm using mine to charge my rear battery, and really enjoy the ability to turn the voltage exactly where I want it using the built in pot. My AGM battery likes a little more juice for longevity so I'm able to turn it up a little.

Flawless performance now for 18 months on lots of rough surfaces.

 

[jblueridge]

I have two wires that go through the left side of firewall. They pop out behind the glovebox.
Yes, ground all to the body or chassis.
I used a circuit breaker in the spot you plan for a in-line fuse.

 

[blastronaught]

Still waiting on harness stuff and converter. However, got the radios wrangled up into a double-din type thing. The radio came with the usual cage thing that the body would slip into, but the LC doesn't need those and mounts in a way I think is better. So I cut that cage part up and reused it to make a a filler piece that nestles next to the smaller bodied ham and takes up the dead space. Went ahead and mounted the switch into that. It took a lot of drilling and trial fitting, but I think I got the radio mounted just right and the dash piece sits on it just right. May repaint the switch panel, ended up a bit too glossy I think. Interesting to note with this radio that even though I hooked up the accessory wire to an ignition-dependent 24V supply, it can still be turned on without the key in place? I assume this will have a parasitic draw on the battery even when off then right?

 

[danmcph]

Fantastic Info!

 

[jblueridge]

If the radio has a clock, it will draw power 24/7. Sometimes power is needed for “remembering” stereo settings, radio channels, etc.
Use an ammeter at the battery to measure current draw with key off.
Should be no more than 80 ma.
Mine is about 25 ma.

 

[blastronaught]

Thanks Jb, I'll give that a check. Routed a wire through the firewall by following what look like the heater lines, which gave me a shorter run and pop out right by the battery. Planning on routing it with a loop before going through the grommet to prevent water from following the wire into the cabin. I am a little woried about having created a gap in the grommet, I can see a little bit of daylight from inside the cabin. Thoughts on sealing this better? The heater tubing has a soft sleeve on it too which the wire will hopefully settle into nicely. The new wire has the yellow on the shrink tubing in the photo.

 

[jblueridge]

Where does the wire pop out on the cabin side?
Those might be your ac pipes.

I had a water leak made by running extra stuff through firewall grommet.
I cleaned the engine side as well as I could then dribbled some flowable silicone on the grommet and wires.
silicone

 

[blastronaught]

You are probably right, they do look much more like pressurized lines, i.e. AC. Picture below where they come out, down low on the passenger (left) side footwell.

Got a lot of mounting and wiring in today. Used a piece of stainless scrap I had that worked out perfectly for a new mounting bracket. Needed a new mounting solution to fit everything in above the glovebox, which after considering my options seems like the best. Fortunately, Toyota blessed us with a lot of drilled and captive nuts on the original bracket, even though in my case several werent even in use. This allowed a lot of flexibility, and with a big slot drilled out in my scrap I was able to mount it down the center and my converter/fuse box on either side. Was able to mount with 3 bolts in it because of this. The fuse panel being mounted here wasn't my favorite, but pulling the glove box out to access it isn't the worst. I did relocate the heating timer, which I had to creative to find room for. Ended up just mounting by one bolt, but it is very light and I have wedged in a bit, so should be alright. On mounting terminals, was careful to heatshrink everything up to the terminal ring itself to avoid shorts.

 

[blastronaught]

Was also lucky to find an accessible but not obvious ground lug on the left side footwell, was an easy run to tap into that. Most of the main wiring for the converter and fuse panel is in. The converter has two grounds (12v and 24v), but they are shared with an internal bus bar. So I ran one ground to this lug, and on the other ground wired the ham ground wire direct. This means the chassis ground wire is really doing double duty... does that mean it should be even larger gage or in a DC circuit is most of the wattage is used up in the devices themselves? If I'm worried about it, is putting a fuse in the ground run a thing?

 

[jblueridge]

I would set it up and run it with whatever 12V loads you have planned for.
While all that is going, just touch the ground wire to check for heat.
In theory, the 12V current exits the converter, goes to and through the radio, then goes back to ground through the vehicle’s steel body. How the 12V grounded current and the 24V grounded interact is nebulous to me.
I grounded my converter, both voltages, to one of the bolts holding the box in place.

 

[hoser]

24v to 12v converter or a battery charge equalizer in this application…. Can any electronics guru tell us why one would choose one over the other?

I have neither but sometimes I test my two batteries and their voltages are slightly off. Both batteries are the same age/type.

It seems a charge equalizer is beneficial to keep the batteries balanced even if you never drew 12v power off it…

Charge and Battery Equalizer : 12V Power Supply

Manage a high current 12 volt supply with Charge Equalizers from REDARC. Ensure that your batteries remain at equal charge. Check out one today!

www.redarcelectronics.com

 

[blastronaught]

Thats a topic tackled several times within this forum and others. This thread is specifically sharing how I was able to install my converter setup.

Good luck finding a 24v mobile ham radio.

 

[hoser]

You wouldn’t need a 24v ham radio with an equalizer.

Okay, regarding your install... have to tested the system yet? Are you getting any RFI with that DC-DC converter and the engine on?

 

[blastronaught]

Personally, I went with the converter as it was easier for me to wrap my head around, and gave me a 12V fuse panel that was easy to put in the cab with 24V leads through the firewall/thinner wires. Haven't tested the radio yet, just now got to wrapping up the details. I'm sure I'll need some additional noise suppression as I didn't even put a choke on it. I also don't have a great ground plane, so I'll be handling all that troubleshooting in threads to come. Parasitic draw with key off I measured to be around 110uA.

Everything is now wired up, and it is a bit of a tight squeeze but I'm happy that everything fits with no modification to stock parts. Flowable silicone looks very promising at sealing the grommet, but only time will tell. Tried a couple antenna locations and landed on back door. Fished the wire through the liscense plate light grommet and along the wires at the door hinge area. Was able to easily conceal it all the way up following the left side of the cab and up into the dash. It did take several annoying connecters: needed a 90 elbow at the radio to clear at the back (PL259), then a adapter from PL259 to SMA, then a 10ft length that could've been more like 5' but I wasn't messing around at this point, then another 13' length SMA to NMO.

A note for anyone installing the same 24V music radio: it comes with this type of antenna jack that had me looking for adapters all over the place. Then, I had the great fortune of playing around with it and found that it pulls out to reveal a connection that works with my stock radio antenna.

Was able to feed the handheld through a hold made for some lights/indicators that my truck didn't have equipped. My truck did come equipped with two holes on the right side by the speaker that appear to have been performed by a previous owner. I was able to use these to mount the handheld clip and keep it secured. This location also makes it easy to use the radio from outside the vehicle.

While I was behind the dash I also replaced all the vent's foam sealing material, which was totally crunchy and useless. We'll see how well that holds up.

 

[blastronaught]

Last thing to do is mount the voltage indicator that kicks on when I turn on the 12V supply/ham radio. Found these super cheap units off amazon. Has anyone happened to come across a switch blanking panel that happens to be a dark, smoked but translucent material? I don't want to cut up a stock one in case this ends up being a problem and I nix the voltage display. If anyone can point towards some cheap regular opaque blanking pieces I'll take that as well and make my own.

One thing I love about this setup is both the radio and ham displays are orange backlight, makes it all looks like it was meant to be together.

 

[blastronaught]