Power source for USB ports

I think it should be possible.

There should be a small fuse box, if I'm not mistaken, at the driver knee side, by the left. That fuse box controls all the accessories.
You could trace the power source of the current cigarette lighter, and hardwired it from there.
But to do that, you'd need electrical wiring diagram for the car, to point you to the right power and ground for the setup.

If you don't have access to an EWD, you'd have to do it the hard way. Visually tracing the harness from the lighter, that gets connected to a dedicated fuse on the fusebox.


Dxta

 

Even if you spend $15 to look at the wiring diagram, that's a ton easier than trying to visually trace. Wire harnesses in these modern beasties are pretty much completely covered in tubing or wrap tape—not to mention the internal routing at the junction/fuse box, shown in the wiring diagram but hidden from the eyes unless you dissect the whole box.

-Chap

 

Chargers are available with multiple output ports that plug directly into the "cigarette lighter" socket.
No modifications or wiring necessary........IF there is enough space to plug it in, that is.

 

The lighter harness locations shouldn't be difficult, if the plastic coverings are
removed to expose the harnesses.

 

What about just looking at the fuse diagram printed on the inside of the fuse box cover. There is also a,similar diagram in the owners manual. Gizmos are made that allow you to tap off of a fuse directly.
Also, every car USB car charger I have seen plugs into the cigarette lighter.


Posted via the PriusChat mobile app.

 

Also remember that a USB device requires 5V, so you can't just connect a straight through socket. They make a USB socket with the appropriate circuitry that replaces one of the black rectangle switch blanks.

Posted via the PriusChat mobile app.

 

I am going to post 4 messages in succession to this thread. I've written a thorough step-by-step guide for USB power access in the front cabin, rear cabin, and trunk door. However, my account is new and I must meet the minimum requirements of 4 posts and 1 day.

I will post my work tomorrow.

Post 1​

 

Post 2

 

Post 3

 

Post 4

Now that I have my minimum of 4 posts, I will post my guide tomorrow. In the mean time, it is available on my google drive:

docs google com/document/d/1rKc8oR8jfRNO-0RCvEjb0nwTV368_tDPGjd4mTsLgFk

 

Incoming post.

 

2014 Prius - USB Power Sources


I recently installed additional USB ports in my 2014 Prius. Below are instruction for three major points on the prius (front, rear, trunk door).

In order to achieve this, I purchased the following items:

1. 4 Port USB Charger with Extended Cable
2. Flush Mount 2port USB with 6ft Cable
3. 4pc Plastic Trim Removal Set
4. Assorted Wire T-Tap and Connector Set or Automotive Terminal Set
5. 2 Port USB Car Adapter

Additional Requirements:

1. Heatshrink
2. Soldering Iron
3. 12g Automotive Wire
4. Pliers
5. Multimeter

Front of Prius

Access The 12v Source
First I removed the center panel (PN: 58818-47040) under the front dash which has the 12v outlet on it (instructions here). My car also has seat heaters, but I believe there would otherwise be an empty accessories port here. When you're done you can simply snap the panel back in place - be sure all connectors are connected or you'll do this twice (speaking from experience). This power source is only on with the ignition.

The 12v Outlet - Connecting
On the rear-side of the 12v outlet, where the plug is, you can remove the cast nylon port by prying 3 clips. Here you will see two components of interest - the body of the cigarette tube, which runs through the interior of the plug, and serves as the neutral connector and then a top plate, which routes through to the center of the plug and serves as the 12v hot connector. I scratched, fluxed, and soldered wires to both, ensuring the positioning would allow the nylon port to reinstall without complications. The USB port will raw approximately 20 watts so wire gauge is not an enormous concern, but if you have spare automotive wire it will be sufficient. Be sure to check your work.

The USB Charger - Connecting
Now that the 12v hot and neutral have been sourced from the previous step you can proceed with the USB charger. In my case I used the smallest small plug terminals, a male on the hot and a female on the neutral. I attached the opposite connector on each of my 12v source wires. Be sure to check your work.​

Checking Your Work
I recommend checking your connections each step of the way - for example, in the "The 12v Outlet - Connecting" step I would recommend confirming your ground wire does not show connectivity to the 12v source plate. You can use 20 ohms of resistance and ensure it does not fluctuate on test points.​

The strategy is two part:

1. Check that your connection works as intended (Resistance drops to 0, or as low as possible)
2. Check that your connection does not work on other test points (e.g., resistance is high when a ground lead is probed and a 12v lead is probed)

​

Back of Prius (Rear Passenger)

Access the 12v Source
I did not find a 12v source in the rear, so I simply ran cables to the front through the center console. The rear panel is removable but be careful! There are two large clips about 2/3 of the way toward the bottom of the rear panel which will not tolerate directional (side to side) movement. The clips require a great deal of pressure to remove successfully but I was able to do this without dents by using the plastic pry set.

I accidentally broke a clip by twisting the panel too much during removal. If this happens just use super glue to set the clip in place and then JB Weld to hold it (wait for the super glue to dry, then apply JB Weld).

I measured the vertical center of the panel and installed the flush mount USB ports about 2/3 of the way down. Remember, this is forever so take your time and double check your alignment (measure twice, cut once ... or measure 10 times, cut once)

There is a gap within the center console housing which will allow some space for the back of your USB ports. I ran the cable along the driver side of the center console - the wire simply tucks beneath the wall of the center console. You can carefully feed the USB port connectors through to the 12v Center Panel I described in "Front of Prius" section.​

Back of Prius (Trunk Door)

Access the 12v Source

This connection is actually 14.5v, but it is within the tolerance of Automotive USB charger I checked - be sure to check. Start by removing all panels on the trunk door. The center most panel will reveal the wiper motor (and power plug). This power source is only on with the ignition.

The 14.5v Source - Connecting
Remove the shortest distance of cable wrap from the wiper motor power harness - this wrap is about 3" long. Tap the wire white wire with blue stripes and white wire with black stripes. Check your work with accessory power on or the motor started. You should a constant find 14.5v across your taps. If your harness varies, be sure to check for the source before tapping.

The USB Charger - Connecting
Remove the body from your 12v USB Adapter. Inside you will find two arms which serve as pressure fit connectors across ground and a central connector for 12v source. Remove the connectors and solder 12g wire on both. The wires will connect ground to the white with black stripes and 12v hot with the white with blue stripes. Double check your work and that your USB adapter is rated for 14.5v.​

I've been running this setup for ~3 weeks now without an issue. If anyone knows a convenient route to install an additional 12v Outlet in the trunk area which will engage with the ignition please share!

 

It's easy. I piggybacked one like this onto the back of the 12v port- pulled the 12v port, did it all on the work bench. Then, snapped it right in to the blank where the seat heater controls go.

I got tired of the USB adapter pulling out of the 12v port.

 

All so-called 12V connections are between 13.8 and 14.8V when the car is on. I have a USB charger plug installed where the cigarette lighter used to be and it has a digital voltemeter. It usually reads between 14.5 and 14.8 when the car is on.
Only when you turn off the car the voltage drops to the actual battery voltage.​