Hardwired USB Charger

by jgeepers

16K520

Intro: Hardwired USB Charger

So I have a situation where I need to mount a wireless camera. The camera is powered by a USB 5v, 1000mA charger, which is supplied with the camera when purchased.

My dilemma is I DON'T have an outlet where I am mounting the camera. However I DO have nearby a old light fixture about 8 ft high on a 10 ft wall. I am no longer using the fixture (an electrical sconce fixture). So I will remove the sconce, and hardwire the USB charger to 120 volt power located behind the light fixture. I want to keep this as clean as possible, and I don't want to install an outlet on the wall.

I did this because I could justify some risks. For example, I know I will likely risk voiding any warranty with my little USB charger, and if the manufacture knew I was hardwiring their USB charger to power my camera, they may void the warranty of the camera too. I'm willing to take these risks.

Other risk: Electrical fire is always a risk, even in the most ideal situations. Did you know you can cause a fire by charging your cell phone (you've heard stories, right?. Sure the batteries are what normally cause the fire, but USB chargers fail too. They can cause a fire. That's why many phone manufactures don't recommend you charge your phone by your bed. This is all rare, but possible.)

In any case, I don't believe for a moment that will happen to me with the charger, in the manner in which I am doing this. How can say that? Because I am enclosing the final project (what you see pictured) in covered, metal electrical box. THAT will eliminate the risk of fire of the USB charger in my case. Could I do this WITHOUT enclosing the charger? Sure, but I don't think it is wise.

Disclaimer: This is how I did this project. I'm not suggesting you do it. However if you DO choose to duplicate this project, please do it at your own risk. Electrical work is inherently dangerous. Please do NOT attempt this project if you cannot do it safely.

So if you want to how I accomplished this...read on.

STEP 1: Supplies

My supplies

- The charger of course

- File

- Solder

- Mini torch or soldering iron

- Flux

- Wire (I'm using 18 gauge rated for up to 5 amps, even though I won't come near drawing this.)

- Wire strippers

- Helping hand (optional)

STEP 2: Prep

I filed the two leads first.

I cut shrink tubing to size and had it ready.

STEP 3: Solder

I can't photograph and solder the wires onto the leads at the same time, but this is pretty straight forward.

I threaded the stripped wire through the hole for some added strength.

I used flux. I didn't pre-tin.

Since I used a torch, I needed to work FAST. I did NOT want to overheat the leads and risk melting the casing of the USB charger. If I was in doubt, I could have used an soldering iron to play it safe. (But I could have overheated the leads with the iron too.)

STEP 4: Shrink Tubing

After I my soldered wires cooled, I "shrinked" on some tubing for each lead, I put on an additional piece of tubing as shown on the wires. I did this because I had split the lamp chord and wanted it to be brought back together for a little added strength and stability.

I used thin wall tubing rated to 600v.

STEP 5: Final

I can now safely hardwire it to a 120v source. There is no polarity on the charger (at least on my USB charger there isn't) so I'm not worried about which lead goes to the hot wire (the black wire) or neutral (the white wire).

Again, I am keeping the charger in an approved covered enclosure, one big enough to dissipate heat. Chargers do get warm, but I've never had one get so hot that it would melt plastic. I first mocked this up and tested it out for a day to monitor it. My wireless camera doesn't have much of a draw, so I'm not concerned about heat at all.

Feel free to share your thoughts and comments.

11 Comments

TimB78 2 years ago

That's the issue with these latest "outdoor" security cameras, they run off USB and the plugs aren't rated for outdoor use. I have several wyzev3 cameras and ended up running the USB wires right thru the walls, 3 I actually drilled holes right thru using a long drill bit and 1 I was able to fish thru at a light location. I recently found a product that looks like a screw in lamp base, screw in into an existing light socket and has 2 USB plugs on the side then you screw the bulb right into it. It's not rated for outdoor use but I'm sure it will work ok if it's in an enclosed outdoor light. This instructables is ok but I'm worried about it failing due to water or even condensation getting in there and shorting it out. I've had outdoor rated dusk till dawn sensors rust out and fail and they were specifically made for outdoors.

aolbob 3 years ago

Soldering 110v wires is a bad idea and I'm sure violates code everywhere. Unlike low voltage, if the current flow makes the connection hot enough to melt the solder and the wire becomes dislodged, the risk of fire is very high since the dislodged wire can short. Low voltage doesn't spark and rattle and cause fires. There are other ways to secure high voltage, just don't ever solder high voltage wires together. This is electronics 101.

An alternate solution is to use an extension cord and cut it in half. Use the female side to connect to the USB power supply.

louap 3 years ago

You might want to crack that usb brick open and see what is inside. You miiiigggght just find out that those prongs are, yes, soldered to to the circuit board on the inside. So, no, a proper solder joint is not a fire risk in this (or most) situations. In fact, many years ago prior to wire nuts, it was the standard. And no, soldering is not reserved for low amps. For example, the heating elements on my dishwasher are soldered to the circuit board. I know this because it failed and I had to re-solder it. But it did not spark or make a fire. It just stopped working. It is not code because to do it correctly requires skill and time, two things that might lead to lots of improperly soldered wires. Done properly, soldering high voltage and even high amps is excellent. Now, in this situation, the metal alloy of the prongs may not be a good substrate to accept the solder. Probably on the inside of that brick, the wires are welded to the prongs and then those wires are soldered to the circuit board. Also, that usb plug is at most pulling 10 watts, or less then .1 amps at 120v. Not exactly a tricky connection to make. Anyway, what he did is not code, but code and being safe are not necessarily the same thing.

dincon 3 years ago

1/2" cord grip. Here's one from Lowes but you can get nylon on Amazon (in bulk) and other places. Ideally you want the wire to be a round cord but you can use electrical tape to create the bulk or squirt some silicone seal into the hole with the wires and then tighten down the fitting to compress the grommet and sealant around the wires.

DJL51 4 years ago

Why not simply convert the light fixture to a proper receptacle,and plug-in the charger???

User20201 4 years ago

Because some people still need a light fixure maybe with a ir sensor for security

dincon 3 years ago

Also, because it is outdoors and the USB adapter isn't weatherproof. Sure, it's under the eave of the house but that's still outdoors.

RincewindT 4 years ago

Putting aside the code where you live, and assuming you have a circuit breaker. The standard range for light fixtures could be around 10amps (with a corresponding breaker for that circuit), if you change a section of this to 5amps and you had a short circuit with the usb charger... the 18awg section you have added from the fixture to the charger could burn and the circuit breaker will not jump in time to save your home... If your home insurance insurance picks up on that then you are not covered.... Assuming the set-up needs around 1 amp, add a 2 amp fuse between the fixture cable and you 18awg (you may need to fuse both cables to be on the safe side of things). If one day you need to change a fuse you can thank me for still having a home (overdramatising but who knows ;-) )

jorabi1 3 years ago

Basically all he did was extend the ac prongs. Why is this any different than plugging it into an outlet? Are you saying he should use heavier gauge wire? Also if he adds an inline fuse, where do you want him to put it?

RincewindT 3 years ago

He needs a cable that is at least the same gauge as the outlet (assuming the installation is correctly set-up), a proper connection between the cables and an enclosure for the new CABLE. Forget the comment on the fuse, just have a proper extension of the cable for the required gauge in the house installation, not less). Thing here is he worries about the warranty on the charger, camera and charger enclosure, but the smaller gauge cable (I guess also not enclosed) could burn down the house... Specially with some dodgy cheap chargers...