1. 8 gauge positive wire from the positive battery terminal to the fuse block
a. I am going to look for marine-grade wire on genuinedealz.com
SAE J1127 or SAE J1128 is my preferred choice. That's easy to find on Amazon. You want high count of fine strand conductors. That makes for a flexible cable that is not only easier to route, but will stand up to flex and vibration.
Good choice, I used on of those on my 2011 F150. Word of advice: The terminal screws will clamp the fuse in place when you tighten them down. When you install all this, leave the fuse out and the screws loose, or you'll have a hard time getting it in.
3. 30 Amp Auto Relay
a. I would prefer to have one that is sealed/waterproof since it will be under the hood. Do I need to use one that specifically says it is sealed or are the typical name brand relays usually sealed (EX: Bosch or Dorman)?
b. believe the relay should be mounted after the 40 amp fuse but before the fuse block - also in the engine compartment?
c.
https://www.amazon.com/Dorman-88069-Universal-Pin-Relay/dp/B00NF0ICSO/ref=sr_1_5
crid=24495P6MVC0QC&dchild=1&keywords=30+amp+automotive+relay&qid=1594730416&sprefix=30+amp+auto%2Caps%2C156&sr=8-5
If you are going to fuse your system for 40 amps, then you'll need a 40 amp rated relay.
You want it after the fuse, the fuse is there to protect the wiring and everything attached to it, so a short jumper from the battery to the fuse, then everything goes after the fuse.
30 amps would probably be just fine for what you are doing, but you'd need to replace the 40 amp Maxi-Fuse with a 30 amp fuse. If you changed your system to 30 amps, using something like a Lind shutdown timer instead of the fuse would give you more options. It wires into the ignition and will automatically turn on when you start the engine. When you shut the engine off, you can set a timer for how long the radios will remain on. It's easy to wire a manual trigger switch to it to allow you to turn on the radios without starting the vehicle.
4. Fuse Block
a. I liked this one from Blue Sea Systems because it has a cover and places to label the wiring
b. I looks like this one can handle up to 6 devices/circuits?
c.
https://www.amazon.com/Blue-Sea-Systems-5025-Blade/dp/B000THQ0CQ/ref=sr_1_1 dchild=1&keywords=Blue+Sea+Systems&qid=1594729133&sr=8-1
Yes, that will work, the one you linked to has several options depending on how many circuits you want to add. BlueSea makes good stuff.
5. DPDT Toggle Switch
a. I have been chatting with ladn about his setup that uses a DPDT switch. I like the idea of having 3 power modes - all radios OFF, radios on with ignition ON and all radios always ON
b. I am trying to find a DPDT switch that will fit in the OEM center bezel slot. The main one I have found so far is on Amazon, but it looks like it is probably from a Chinse company.
c. Is this switch sufficient for my needs?
d.
Amazon.com: Bandc Marine Boat Car 7 Pins 2 Light Blue Led On-off-on Rocker Switch Dpdt Waterproof 12v 24v: Sports & Outdoors
Yes. All that sort of stuff is going to be made in China, some of it is good, some is crap.
Only issue I'd see is there is a risk of leaving it on. Installing a lamp might be a good reminder, or just using the Lind timer I mentioned above. The Lind timers cost more, but make the system pretty much fool proof. I use them in my own personal vehicles, and I never have to touch the radio. It turns on with ignition and will shut itself off after about 30 minutes after shutting the truck down. If I want to turn the radios on without starting the engine, I just turn the key on for a second and it turns it on.
These are the other questions I noted down while reading through the threads:
1. For the fuse block ground - should I run a local ground near the block to the Jeep body? Scrape off some paint and screw the ground in?
2. Also for the fuse block ground - do I need to also run a negative ground back to the battery negative terminal?
3. For the radios - the positive wire runs to the fuse block, but how should I wire the grounds for each radio? Ground them by running a wire from the radio chassis to unpainted metal or do they also need a negative battery ground. Both power cables for the MXT400 and the IC-2730A have fuses on both the positive and negative power leads.
There are two trains of thought to this. Both are valid.
1. Run the negative to a local grounding point. That uses the vehicle body as the return. If the battery strap for the negative terminal is in good shape and properly sized, there's no issue with this. The added benefit is that you are grounding your radios close by and that can solve some RF noise issues. It also saves you some money on wire. The existing vehicle electrical system does this.
2. Run an 8 gauge wire from the fuse block ground all the way back to the battery and ground to the body where the battery negative lead is attached. This gives you a return path that doesn't rely on the body. What it doesn't solve is issues with an undersized negative strap connection from the battery. On newer vehicles (probably not your Jeep) they have a hall effect sensor on the cable running from the negative terminal of the battery to ground. This is used to monitor current consumption of the vehicle and control things like alternator, auto shut off, etc. Bypassing that by running your ground all the way back to the negative terminal can create some issues. Usually the manufacturer will call this out in the manual.
I've never had an issue with grounding to the body. Those that claim it can create problems with corroded negative straps from the battery to ground are often people that do not maintain their vehicles and wait for things to completely fail before addressing them. I've never had that issue.
You —do— want a short ground for the radios to the body. This can prevent some RF interference issues. Relying on l-o-n-g paths to ground for radios, either through the antenna mount or the power feed is not a good idea. Long wires become good antennas and can either pick up noise or radiate noise. No matter which of the two options you choose above, run a short as possible ground strap from the radios metal chassis to a body ground point. I've solved some nagging issues with this. DC power ground and RF grounds are two different things.
Your fuse block has a negative buss, so you can use that for your power ground. Running the negative power lead for the radios to that is a good option. Just make sure you don't ignore properly grounding the radio chassis with a short ground strap.
Grounding the fuse block ground buss can use one of the two options above, either using an 8 gauge wire to the body, or run it back to the point where the battery grounds to the chassis/body.
4. Also on the radio grounds - I have both of them mounted to an overhead console that is metal in the Jeep. I'm thinking I could remove some of the finish on the console and attached the grounds to it - does that work properly?
See above. You need to consider your DC power ground and your RF ground. They can be the same thing if you do them right, or you can make them separate. Here's what I'd probably do:
1. Ground each radio to the metal box using a short strap from the radio mounting screw to the box. That'll work as a good RF ground.
2. Ground the radio box with a short strap to the vehicle. Sounds like that's going to be the windshield frame or roll bar. Make sure that the windshield frame or roll bar has a good connection to the vehicle body. Paint can get in the way….
3. Run the positive and negative power leads for each radio back to the fuse block.
Might be easier to just install your fuse block in the radio box, if it'll fit.
5. Which fuse block fuses are correct for the radios? The MXT400 can push up to 40W and the IC-2730A can push up to 50W. 20 or 30 amp fuse for both?
Check to see what the manufacturer recommends. Likely they have a fuse installed on the power leads. You don't need both fuses, you can use the one in the fuse block and run the power straight to the radio. I think you'll find that the radios will either have 15 amp or 20 amp fuses. 15 amps should be sufficient for a 50 watt radio.
6. I currently have
14 gauge Autocraft auto primary wire from Advance Auto running to the radios in the Jeep cab. Is this wire sufficient to use as well?
Looks sufficient. The 'right size' depends on how long the cable run is. As the wire gets longer, the resistance increases and that will cause voltage drop. Keeping your power leads short is a good idea. Running the fuse block in the radio box is a good idea to reduce the length of smaller power cable runs. Rely on the 8 gauge wire from the battery to do the hard work. Keep the power leads that run from the fuse block to the radio short.
7. I'm not quite clear on how to wire up the DPDT switch - if you could point me towards any info on that it would be much appreciated.
You'll need a single pole double throw switch with a center off position. Double pole will be fine, but you won't use half of it. Might be easier to find the DPDT switch, though.
The center connection (Common) will be the connection to the relay coil. The other two connections will be used for:
1. full time power, that'll need to come off the battery or full time power source. Fuse it for 5 amps or so, just enough to run the relay coil.
2. ignition controlled power. That'll need to come from an ignition switched source, and also needs to be fused.
Or, just use the Lind Timer like I mentioned above. You'll still need a fused ignition controlled power feed, but it'll take care of the on/off for you. Cost more, but it's pretty much fool proof.
I apologize in advance for all the questions, but I think this should round up the rest of the install details. All of this information has been incredibly helpful.
No apology necessary, those were good questions.
