EZ-Pass transponder mounting on refreshed nosecone-less Model S

[SDRick]

Thanks.. I did the same thing, but I live in Florida and have a E-pass. I guess it isn't quite a strong.

If that works, I would spray paint that thing black.

 

[Soundchasr]

Here you go:

I had mine mounted this way (also in PA) and it worked great for a while. Now, it doesn't work at all. So frustrating!!

 

[cdhowe]

I'm the person who started this thread. The Natick, MA EZ-Pass center gave me a new smaller transponder with a fresh battery. To ensure that I'm doing a scientific test of the mounting, I have reverted to mounting my new transponder in the area to the right of the rear view mirror with the arrows up as shown. About 1/3 of the transponder hangs past the black area, but I figure this will provide me with a good baseline test.

I've only had the transponder scanned once so far, but it scanned successfully that time. More data as I collect it.

 

[Soundchasr]

I'm the person who started this thread. The Natick, MA EZ-Pass center gave me a new smaller transponder with a fresh battery. To ensure that I'm doing a scientific test of the mounting, I have reverted to mounting my new transponder in the area to the right of the rear view mirror with the arrows up as shown. About 1/3 of the transponder hangs past the black area, but I figure this will provide me with a good baseline test.

I've only had the transponder scanned once so far, but it scanned successfully that time. More data as I collect it.

View attachment 185127

Why did you mount horizontal, not vertical?

 

[JPP]

If that works, I would spray paint that thing black.

I wrap mine with black electrical tape--virtually disappears....

 

[cdhowe]

Why did you mount horizontal, not vertical?

I mounted mine horizontally because others have reported success doing so, and I think it looks a bit better. If it fails, I'll try vertically, and then move to rear panel and rear window mounting. But I want to gather data on the success rate in each position to better gauge the performance of each location.

 

[ScotMaine]

I'm the person who started this thread. The Natick, MA EZ-Pass center gave me a new smaller transponder with a fresh battery. To ensure that I'm doing a scientific test of the mounting, I have reverted to mounting my new transponder in the area to the right of the rear view mirror with the arrows up as shown. About 1/3 of the transponder hangs past the black area, but I figure this will provide me with a good baseline test.

I've only had the transponder scanned once so far, but it scanned successfully that time. More data as I collect it.

View attachment 185127

Thanks for the trial, and keep us updated! That seems like the logical location, and perhaps the "black area" will get larger on future models, since the EZ Pass is fairly standard!

 

[bhzmark]

mine works better upside down, so the writing from the passenger seat is upside down. works perfectly. the other way is wasn't detected about 20% of the time.

 

[headcase]

If anybody is interested. Here's a E-ZPass taken apart. The parts are horizontally aligned.

If you are looking at the E-ZPass from the front (where the barcode/label is) note that the antenna part is on the right. So when you mount it make sure the right part of the E-ZPass is on the non-coated section of the windshield.

View attachment 184756

Disclaimer, I'm no expert on EM systems or radios, I just like to read a lot.

According to various documents on the Internet (http://www.root.org/talks/BH2008_HackingTollSystems.pdf), it seems that the E-ZPass transponder is vertically polarized (perpendicular to the surface of the Earth). So while mounting the E-ZPass sideways (vertically) may work, it is probably better to mount it horizontally. Or in Tesla's case, upside down with the right over the black non-coated area.

Additionally, the communication protocol for the transponder systems seems to be governed by something called "Title 21". The toll booth antenna sends a carrier signal to your transponder. And if the antenna of your transponder is in a position to receive it, it will modulate (backscatter) the a hardcoded frame back. This can take up to 1s on normal toll booths (not the express ones). While this may sound like its quick, the Tesla is quicker.

With that said, I did all this research to see if I can come up with a more elegant way to mount a transponder than a) on the winshield b) on the bumper c) taking apart a nosecone on the refresh by going through the frunk d) mounting in the rear trunk. (Mounting on the front will allow earlier detection aka less slow down at the booth, thusly less "unable to read" anxiety.)

My current idea is to create some sort of sticker antenna that I can mount on the non-coated part, and paint it black. With the chip/transistors hidden away inside the rearview/autopilot cradle. It'll likely fail, but should be a fun project/learning experience nonetheless.

I'm really curious to know if you had any success with building an antenna...

 

[Tangible]

I'm about to hit the Mass Pike with my new 90D for the first time. MA has eliminated all toll booths and now has a gantry system, in which EZ Pass transponders and license plates are read as cars pass under them at full highway speed.

Has anyone had experience with these? I'm having trouble sorting out all the contrary advice about where and how to mount the EZ Pass.

 

[Yinn]

When I picked up, my DS told me to mount it directly under the rear view mirror. He said it is the only place that seems to work consistently, every where else is different degrees of readability.

I followed his advice and mounted mine dead center, directly under the black plastic piece that holds the mirror/camera. I have not had an issues with any tolls reading the EZPass using a variety of retrofitted tollbooths as well as overhead/non booth readers (those that are basically an overpass to prevent slowdown)

 

[singleview]

When I picked up, my DS told me to mount it directly under the rear view mirror. He said it is the only place that seems to work consistently, every where else is different degrees of readability.

Would you kindly be able to post a picture of how/where you hung your EZ-Pass transponder? I tried directly under the rear view mirror, but does not seem to work consistently. Thanks!!

 

[Tangible]

I stopped at an ez pass service center on the mass pike after passing under several gantries with my transponder mounted at the top of the windshield to the right of the rear view mirror assembly - where I gather the black area used to be on the older cars. They were unable to tell me if my transponder was being read, saying it takes about two weeks for the data to be available. (Apparently someone walks slowlyinto Boston HQ with it, or the speed of light has been slowing down. )

However, she said it doesn't matter if it doesn't work, because the system will read my plate and charge me the same toll as if it had seen the transponder. This is confusing, as the new state website says pay by plate carries higher tolls.

Sometimes I miss having a little bucket of quarters to throw in the hopper.

 

[ssheth74]

I bought a couple toggle bolts at the hardware store and mounted the black EZ Pass transponder in the black grill to the right of the radar (drivers's side). The EZPass has worked well in Maine, NH, MA, NY, NJ, PA, and VA. Most folks don't notice it. Do you?

I'm very happy I don't have the transponder cluttering up my windshield or my license plate.
View attachment 184858

I've done the same thing but didn't even bother with toggle bolts. Just used some very heavy duty zip ties to mount the transponder to the black grill and its still firmly on after 2 years of driving (including lots of salty roads..)

 

[Yinn]

Would you kindly be able to post a picture of how/where you hung your EZ-Pass transponder? I tried directly under the rear view mirror, but does not seem to work consistently. Thanks!!

 

[Science fan]

I live in a gated community that uses transponders to open them. I have a P90D refreshed model. So far the only solution I have is opening the sunroof and holding the darn thing in the air. I share your interest in an answer to this one.

I also live in a gated community and have a refreshed Model S. There is room for a sunpass on the windshield "opening" but not for the community pass. I have a transponder bar that I hold up to the window on the side that the community "read" device is on. It won't read through the front window, but it will read through the side windows. No need to open the window to get the gate to open.

 

[Tangible]

I've now been able to confirm that the new gantries on the Mass Pike can read my transponder mounted to the right of the rear view mirror.

 

[Kross]

I'm the person who started this thread. The Natick, MA EZ-Pass center gave me a new smaller transponder with a fresh battery. To ensure that I'm doing a scientific test of the mounting, I have reverted to mounting my new transponder in the area to the right of the rear view mirror with the arrows up as shown. About 1/3 of the transponder hangs past the black area, but I figure this will provide me with a good baseline test.

I've only had the transponder scanned once so far, but it scanned successfully that time. More data as I collect it.

View attachment 185127

Sorry to revive an old thread, but wanted to see if you've been happy these past few months of driving, having mounted your new EZ Pass horizontally (with some of it sticking out of the black area)?

I just got a 2016 (refreshed nose) Model S. My wife's car has a smaller EZ Pass like yours and we took it with us in the Tesla this past weekend. It did NOT register 75% of the time at the toll booths. We tried holding it up in the shaded area in nearly ever conceivable alignment. Trying to figure out what to do for the Tesla; am looking into those License Plate mounted transponders too.

 

[meeb]

I have a 2016 refreshed Model S. Orientation I ended up with was a bit different. I've removed the from license plate bracket and don't want it there just for the license plate transponder, so experimented with just about every way to mount it. I first mounted it like shown in that picture, and found I'd have to go really slow or otherwise work about 25% of the time. Some roads tended to work better than others with that method.

I searched and found some images of a EZ Pass Transponder teardown that seemed to show the antenna for this particular transponder model to be on the "right" side of the transponder. I've mounted it sideways as shown in the image - rotated 90 degrees counter clockwise with the right end in the black area of the windshield.



I generally find that this orientation works - express EZ Pass lanes, going through the slower lanes, etc. There's been 12 occurrences where it hasn't worked resulting in a EZ Pass VTOLL (where they don't know what tag went through, so my license plate ends up on the bill), out of 525+ readings total. A majority of those 525 would be where it'd be two scans for 1 transaction, so the hit rate might be even better.

Most of my readings are on the PA Turnpike, but also have success on roads operated by NJ Turnpike, Port Authority NY/NJ, Mass DOT, Delaware DOT, and Maryland Transportation Authority. The 12 failures have been a fairly mixed bag,

 

[Scott216]

I have the refreshed Model S. On the Model S front licence plate bracket (assuming you have a front licence plate in your state) there is an opening that makes for a snug fit for the small EZ-Pass transponder. I remove the "velcro" stips from the EZ-Pass to make it a bit thinner, then just shove the EZ-Pass in this gap. It stays put. To find the gap place your hand palm up on the underside of the license plate bracket, the part that wraps under the nose-cone and toward the grill, as you move your hand toward the back of the car, you'll feel the gap the bracket makes against the nose-cone. The plastic licence plate bracket is flexible enough to bend slightly as you shove the EZ-pass in. I've had it like this for a year, not problems. And on only takes 10 seconds to install (removing the velcro strips takes longer).