How to Install a USB Charger on a Motorcycle




There are plenty of items that could benefit from accessory power on a motorcycle. Dedicated GPS units, audio systems, and phones are just a few. I installed a RAM phone mount on my bike a while back so I can use the GPS without pulling my phone out over and over. GPS apps drain a phone battery more than just about anything, so I decided to install a USB charger to fix that. This instructable is for a CBR250R, but the principles can be used for most motorcycles. This is how I did it.

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Step 1: Where to Mount It.

I want the USB port to be close to the device it is charging. I'd rather route the power cable through a noisy, hot, dusty bike than a USB cable. I decided to mount it on the fairing, next to the instrument cluster. This location does not move, so I don't have to worry about things pinching or failing prematurely. This location will also keep the USB cable short.

Step 2: Things You'll Need

To mount a USB charger in the location I selected, I will need these things.

USB Charger -

Extension cable -

Fused battery terminal kit -

Zip ties -

Double sided tape -

Side cutters -

Hex key (5 mm) -

Step 3: Preparing the Cable

It's going to be easier to install this cable if you assemble it ahead of time.

  1. Snap the USB charger into the extension cable
  2. Snap the fused battery connection cable into the extension cable.
  3. Cut the double-sided tape to fit the profile of the USB charger
  4. Peel the backing off the double-sided tape and press it onto the USB charger
  5. Apply firm pressure on the double-sided tape for approximately 30 seconds.
  6. The cable is ready to install.

Step 4: Access the Battery

To make the necessary connections to the battery, we'll need to access the battery. The battery in a Honda CBR250R is located under the seat.

  1. With the motorcycle key, open the rear seat/trunk of the bike.
  2. With the 5mm hex key, remove the two seat bolts.
  3. Lift the rear of seat and pull back to remove the seat
  4. Place the seat in a safe place.
  5. The battery is now accessible.

Step 5: Mount the USB Charger

We want to mount the USB charger in a location where it won't hinder steering or block the instrument cluster. The CBR250R has a nice place just below the instrument cluster that works great. Here's how I did it.

  1. Clean the mount location with rubbing alcohol
  2. Pull the back off the double-side tape on the USB charger.
  3. Firmly press the USB charger onto the location you have chosen, for approximately 30 seconds.
  4. The USB charger is mounted!

Step 6: Install the Wire

We need a pathway to route the wire without leaving it exposed to the eye and elements. We don't want the wire contacting or tying to anything that moves or generates heat, and pinch points should be avoided. Here's how I did it.

  1. Remove the hex screw on top of the side fairing, near the handlebars
  2. Gently pull back on the fairing and slide the wire behind it, avoiding the mounting flange for the screw you just removed.
  3. Guide the wire along the fairing, using zip ties where possible, keeping the wire hidden and safe from hazards.
  4. Route the wire into the battery box, avoiding seat pinch points.
  5. Remove the battery bolts.
  6. Install the black ring terminal to the negative battery post.
  7. Install the red ring terminal to the positive battery post.
  8. Your wiring is installed and the USB charger should work.

***I routed the connection between the extension cable and the fused battery connection cable to the trunk of my bike. This will allow me to easily pop the trunk and connect a Battery Tender to my battery if there is any reason I can't ride it for an extended period of time.

Step 7: Clean Up the Install

The wires are installed, but I like to keep things organized.

  1. Zip tie any loose wire along the pathway to locations that will keep the wire from being pinched. DO NOT tie to the front suspension or handlebars if you can avoid it.
  2. Reinstall the hex screw on top of the fairing. If the wire is on top of the mount flange, push it beneath it so it doesn't get pinched.

Step 8: Reinstall the Seats

With everything installed and working, it's time to reinstall the seats.

  1. Slide the seat, tip down, until it engages with the hooks on the bottom
  2. Lower the rear of the seat onto the mount flanges.
  3. Install two hex bolts with the 5mm hex key
  4. Slide the rear seat, tip down, until it engages with the two metal hoops.
  5. Push the rear of the back seat down until it clicks
  6. The seats are installed.

Step 9: Connect the USB Cable

Your USB charger is installed and ready to use. DO NOT use the charger for a prolonged period of time without the engine running. It may drain the battery on the motorcycle. If you get off your bike to go somewhere, it is probably best to unplug your devices and take them with you for security reasons anyway.

Step 10: You're All Done!

Use this information to make your riding more convenient, not more dangerous. Don't watch Breaking Bad or anything else while riding.

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    12 Discussions


    Question 4 months ago on Introduction

    One thing I noticed, as other pointed out, is that this is directly to the battery. I noted that others said they ran it to other items that only powered when the ignition was on. would putting a power switch in-line with this solution also work? I don't want to chance splicing into something and screwing my power / lights up, and I figured that a simple rocker or toggle switch attatched to the handlebar out of the way would likely be an ideal solution?


    Tip 5 months ago on Introduction

    Hi, nice explanation...but i would advise not to connect the + wire to battery, instead you should find a wire with positive charge that would only give energy if the ignition key is on. The main reason is the abusive use from anyone that finds out that charger is working without the owner is nearby, draining the battery.


    3 years ago

    Man, great idea. I really could use a phone mount on my bike too. I have a heater system that runs off the battery as well, and what I did to prevent drain while the battery was off was install a relay that is triggered by the tail light. Has worked flawlessly for years now.

    2 replies

    3 years ago

    Not sure if its best idea to hook up charger directly
    It could drain your battery if you forgot to plug something out of it

    4 replies
    Stonewall CraftworksCekpi7

    Reply 3 years ago

    It's something that you really need to be careful with. You can connect it to the low beam headlights, but I don't know how this would affect the Battery Tender.

    Cekpi7Stonewall Craftworks

    Reply 3 years ago

    good idea would be to connect it so when you turn your key to on position it would work but when you turn your bike, off usb charger would also turn off

    Stonewall CraftworksCekpi7

    Reply 3 years ago

    That's what wiring to the low beam would do on most bikes, as motorcycle headlights come on with the key. I don't think the Battery Tender would work with that, but I could be wrong. You could possibly install a manual switch to turn it off when not in use, but a state-sensing circuit would remove human error.

    You could also just wire in another fused pigtail directly to the battery specifically for the Battery Tender, and wire the charging/accessory line to the low beam.

    Cekpi7Stonewall Craftworks

    Reply 3 years ago

    i have experience with cars but not so much with bike :P
    well if low beam light gets 12v like on car then it should be fine
    or you could add relay on light that would disconnect battery tender when your bike is turned off