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Question Cable routing from 12V accessory socket

revmatch

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Hey folks,

Just put down a deposit on a 2020 NC750X DCT the other day and, although the bike isn’t arriving until May / June, I’m eagerly planning my accessories.

Regarding the Honda 12V accessory socket, my understanding is that it lives inside the frunk — is that correct? My dealer will be installing it, but I’m curious what’s the easiest way to run a USB cable from the 12V socket to a phone or GoPro mounted on the handlebars. I’m having trouble visualizing how the cable would go from inside the frunk to outside the bike.

If anyone could let me know and/or post a picture, I’d appreciate it. Thanks!
 
The battery, fuses, and relays are located above the engine and just in front of the frunk space. The battery is accessed by removing a maintenance panel in the frunk that is secured by two screws. The battery compartment is not sealed and there are openings on either side of the battery that allow the USB cable to run forward along frame members to the head stock and up to the handlebars. The maintenance panel could be notched for the cable to pass from inside the frunk into the battery compartment. Myself, I used a flat USB cable led up and out of the frunk and just shut the frunk lid down on it. There is a rubber gasket in the lid that conformed to the cable passage. I didn't use the Honda power outlet because it's only fused at 2 amps and I need minimum 15A to run a tire pump I always pack. I wired my own power outlet and installed it inside the frunk wall. I didn't use a phone for navigation and it wasn't on the bars 100% of the time so this worked for me. I use a dedicated GPS and led the GPS power cable out of the battery compartment along the frame like I described above.
 
3 parts to the install
  • relay kit that's plugged into a panel in the battery compartment just to the left of the battery, consists of a relay that activates when the ignition is on and a 7.5 amp fuse
  • an accessory harness that's below the seat on the left side and under the body panels which plugs into wires that lead to this rely kit, it has 3 outlets (2-12V + Ground, 1-12V + Ground + 5V on low beam)
  • a 12V accessory socket that plugs into one of the outlets in the the accessory harness and is installed in a hole drilled through the left side of the frunk & opens into the frunk
Note that the fuse powers all current draw through the accessory harness as well as the OEM heated grips, if installed. Consequently, you're not gonna be able to draw much power from the accessory socket before blowing the fuse. Better, I think, to wire directly to the battery through a separately-fused connection. That way you'll have much higher power capacity ... but you will loose the "switched on with ignition" feature. Also, FWIW, my personal preference is for a bulkhead-mounted SAE connector.

EDIT: yeah, dduelin's right - I'd forgotten that the OEM socket had such a small fuse. Just makes the current limitation that much worse.

It's possible to install a 12V->5V power supply for USB either at one of the accessory harness connectors and carry on your USB cable from there or wire from the accessory harness to a USB power supply located elsewhere. like at the handlebars. I'd suggest that you avoid a 12V USB charger that plugs into a cigarette socket if you ride many rough roads - washboard's a killer - 'cause many of these power supplies have a component standing up on their circuit boards that'll break off given enough vibration. I've killed three of 'em riding gravel roads.
 
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...... Better, I think, to wire directly to the battery through a separately-fused connection. That way you'll have much higher power capacity ... but you will loose the "switched on with ignition" feature. Also, FWIW, my personal preference is for a bulkhead-mounted SAE connector.
If one wires the power point off a switched relay or a fuse block powered by switched power you can have "switched on with ignition".
 
As already pointed out, the Honda accessory outlet is fused at a very low amount. The fuse may be hidden in a barely accessible spot, too, depending on how the dealer installs it.

For your application, I would leave the 12 volt outlet in the frunk for charging items left in the frunk. Then run a new fused line from the battery up to the handlebars for handlebar accessories. You can get handlebar mount combination 12 volt/5 volt outlet with a power switch. Leaving USB outlets powered, whether there is anything plugged in or not, can slowly drain the battery while the bike is parked.
 
The battery, fuses, and relays are located above the engine and just in front of the frunk space. The battery is accessed by removing a maintenance panel in the frunk that is secured by two screws. The battery compartment is not sealed and there are openings on either side of the battery that allow the USB cable to run forward along frame members to the head stock and up to the handlebars.
@dduelin Revisiting this now that my ‘21 NC is almost here (fingers crossed), and curious if you have to remove any of the body panels when running a cable from the battery compartment to the handlebars through the body work or if you can just fish it through with them all intact.

I know Honda moved the battery to the opposite side of the frunk on the ’21 models, but there’s still a “maintenance lid” located where the battery was in prior years so I’m hoping you’ll still be able to route cables from the frunk to the handlebars in a similar fashion.

2021 Luggage Box
E3E602BA-222E-40A4-AB73-F64BA93E6EFB.jpeg

2020 Luggage Box
2F71BD19-0B6B-45E8-90F5-29BF15DB0B94.jpeg
 
@dduelin Revisiting this now that my ‘21 NC is almost here (fingers crossed), and curious if you have to remove any of the body panels when running a cable from the battery compartment to the handlebars through the body work or if you can just fish it through with them all intact.

I know Honda moved the battery to the opposite side of the frunk on the ’21 models, but there’s still a “maintenance lid” located where the battery was in prior years so I’m hoping you’ll still be able to route cables from the frunk to the handlebars in a similar fashion.

2021 Luggage Box
View attachment 45101

2020 Luggage Box
View attachment 45102
That sounds reasonable.
 
When you were installing your GPS and ran cables from the battery compartment along the frame to the handlebars, did you have to remove any of the fairings?
I think I removed just upper fairing sections that look like air ducts but remember my bikes were gen 1 with different fairing panels than gen 2 2016-2020 bikes and the ‘21 might be different yet. The panels aren’t hard to remove if necessary to do a good job.
 
I think I removed just upper fairing sections that look like air ducts
For the old-gen models, you definitely have to remove these two to route cables from the battery to the handlebars.

If you want to have really easy access, removing the middle plastic piece (the one above the frunk lock, that you have to take out to change the air filter) gives you totally free access to that whole area, but at the cost of fiddling around with the lock and latch cables.
 
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