If you’re reading this article, you’ve encountered a similar problem to the one that I recently solved: you bought an Echo Show 15 and wanted to either 1. power the device without wires showing, 2. deliver power to the device over a long distance (the included power supply is only 6 feet in length), or 3. avoid installing an AC power outlet. For me, I wanted to accomplish all three of these items: I wanted to run a single Cat6a cable from my PoE network switch in the basement through the wall and power the Echo Show 15 in the kitchen.
After reading dozens of threads online, I couldn’t find any answers to this niche problem. I have experience powering IT equipment over PoE+ (e.g., PTZ cameras, HDMI extenders, etc.) so I decided to give this a try. The typical disclaimer applies — try the below at your own risk.
If you do not know what Power over Ethernet means or how it functions, you will gain a very basic understanding through this guide. Recently there have been advancements in the PoE standard (PoE+, PoE++) and you can deliver significant power over low voltage cables (e.g., Cat6a). You can use a network switch with integrated PoE or a dedicated PoE injector to deliver power over the Ethernet cable. The benefits to PoE for this particular project: You can run Cat6a cable through the wall and at a distance of 328 feet, and provide power and data over a single cable. Also, you don’t need to work with high voltage wiring or pay someone else to work with high voltage wiring.
After reading the manual to the Echo Show 15, I realized this would be tricky for a few reasons.
- It uses 18V. Most PoE splitters operate at 5v and 12v.
- It operates at 30 watts. Most PoE splitters provide max 25 watts.
- It uses a very odd dc barrel plug size of 6.5mm x 2.5mm. Most devices use either 5.5mm x 2.5mm or 5.5mm x 2.1mm.
After some initial research, I found two PoE splitters that seemed like they would work:
- ALFA Networks PoE Splitter
This splitter has a selected output to 18v and max power that exceeded 30 watts. When I tested, it outputs slightly more than 18v at 18.45v. I liked its form factor because it will fit inside a wall mounted to a 2×4 stud.
- Centropower PoE Splitter
While the ALFA Networks splitter has a better form factor, the Centopower is more available online (around $24) and is closer to the mark on 18v in my tests at 18.01v.
Important: The barrel plug cables included in the product boxes do not fit into the Echo Show 15. You will need to order a separate male to male 5.5mm x 2.5mm DC barrel plug cable that is rated to handle 18v.
Keep in mind that this still won’t fit perfectly into the Echo Show 15 because it wants a 6.5mm x 2.5mm. But I didn’t have any problems with the slight “jiggle” in the connection. It’s very difficult to find a 6.5mm x 2.5mm but, if you were feeling ambitious, you could splice the cable that comes with one of the splitters above with the end of the Echo Show 15 power supply that ships with the device. I used this male to male 5.5mm x 2.5mm and it worked great.
Putting It All Together
You will run an Ethernet cable from a PoE+ integrated network switch (that provides at least 30 watts per port) to the Centropower PoE splitter (make sure you set it to 18v) and then run a male dc barrel plug to the Echo Show 15.
Equipment That I Used
- TP-Link TL-SG108PE PoE+ Network Switch
- Cat6a 30 ft cable
- Centropower PoE splitter
- Male to male 5.5mm to 2.5mm DC cord
- Echo Show 15
- Optional: I used a Commercial Electric 1-gang flexible opening wall plate behind the Echo Show
Hopefully this is helpful to other people looking to do something similar. This general approach works for most PoE gear.