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Model S Rear Facing Seat Cooling

Discussion in 'Model S' started by supratachophobia, Apr 15, 2017.

  1. supratachophobia

    supratachophobia Active Member

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    So we are quickly approaching year 3 of Model S ownership and it's always been a goal to try and make the rear facing seats as comfortable/useful as possible even in the hot summers. One would think that Tesla does not care for the well-being of it's 3rd row passengers when you look at how inadequate the default HVAC setup is (turn on fresh air setting, crank to 11).

    All that being said, ceramic window tint + the rear window shade takes care of blocking most of the heat coming in, but circulating air back there is still an issue. Enter stage 1 of my latest Tesla project.

    IMG_20170414_214306.jpg
    IMG_20170414_213627.jpg

    Using a couple different fan templates, I was able to 3D print an adapter of sorts that holds a standard 60mm computer case fan and mounts directly to the car using the stock plastic trim pins and no drilling/cutting/or other wise mutilation to the car. Then I printed a 60mm 90' vent/tube to direct the air straight into those sweaty faces.
    IMG_20170414_220620.jpg

    The current version is a little on the rough side, but it does the trick for testing. I'm using a couple of fans I had just laying around, however the final version will have 2 Delta fans that claim they can move up to 40cfm a piece. These current placeholders can do almost 20cfm, bless them.

    IMG_20170414_220558.jpg

    I don't have the upgraded audio package, so these fans will mount directly to the area where the rear hatch speakers would have gone. I'm currently trying to figure out the best and most tasteful way to install the grill cover back on. Unfortunately this setup will not be completely stealth, but I still think it can be done tastefully and look professional/stock

    IMG_20170415_185649.jpg IMG_20170415_213811.jpg

    The rough idea here with regards to airflow is first and foremost just getting the air moving back there. But the design of the rear hatch trim panels allows for a small bit of air to be drawn through channels on either side underneath the trim that lead up to the panel where the hinges are and consequently right where the cool air from the main cabin gets stuck. However, slots would need to be drilled in that trim piece to open up that source. The headliner would hide the openings for the most part. We will see how the upgraded fans function with both setups, but as for now, this looks to be a very good start.

    Stage 2 is even more exciting because it would involve one or two 120mm x 40mm radiators in that same front trim piece with hoses run from the front of the hatch to the rear where 1 or 2 peltier coolers would be sandwiched between a liquid cooling block and an aluminium heat-sink. The idea there being that the fans would be drawing air up that is chilled as it passed through the heat-sink. I'm currently building this setup outside of the car to test and tweak, but from experience, as long as you can dissipate that peltier heat, those pads will get very very cold.

    But now for the kicker. Unlike other setups that are required to be battery operated or hooked into the cigarette lighter socket, both of these are relying on the already existing 30amp power source in the rear hatch which is completely unnecessary in the summer.... the defroster. Which of course, wait for it, is controlled by the touchscreen. So this setup is nearly stock in it's interface with the driver; just press the button and the system comes on. A simple 2-way switch in the hatch can change you between "Summer" and "Winter" mode for the button function. And while the fan-only solution requires just a couple of amps, the peltier option would still come in at a reasonable 20-25amps depending on what pumps and what cooling plates were used. All well within spec for load and safety.
     
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  2. Xenoilphobe

    Xenoilphobe Active Member

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    Be careful, you don't want to pull any carbon monoxide into the passenger cavity. ;)

    Love the idea to tap the rear defroster!!! that opens up lots of possibilities... like a 4K gimbal using this - as a security camera:
    Yuneec Typhoon H CGO3+ 4K Ultra High Definition Camera
     
  3. supratachophobia

    supratachophobia Active Member

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    For good or ill, the part behind the trim is still within the cabin so there can't be any air exchange to the outside. This was my original plan to go straight with a peltier solution and dump the waste heat outside of the car. Fun fact, the perfect heat-sinks to mate with a 40mm peltier plate are the old AMD K7 ones. Good luck finding those.

    I also really like your camera idea....
     
  4. Xenoilphobe

    Xenoilphobe Active Member

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    I happened to crash my Yuneec Typhoon H and ended up buying another one.. so I have lots of spare parts on hand to play with including a full controller and gimbal.
     
  5. supratachophobia

    supratachophobia Active Member

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    Here is the almost finished product for the final fitting before a flat black coat of paint to better match the interior and trim installation to hide the screws.
    IMG_20170419_215747_01.jpg
    Initial feedback is that it absolutely feels cooler back there just by getting some air moved around. Next step will be testing the peltier cooling solution rig for actual air conditioning or just a second stage of 40mm fans along the front hatch trim piece to further facilitate the main cabin air to get back there.

    I think we are almost there. And none too soon for the hot months.
     
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  6. Xenoilphobe

    Xenoilphobe Active Member

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    That is very creative!
     
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  7. Akikiki

    Akikiki A'-Lo-HA ! y'all

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    Very clever. I can't find the link or reference to it. But a couple of years ago someone invented a add-on center console that mounted into the foot well of the RFS and went between the kids feet. It had a fan and scoop that sucked air in from the rear seat area, down and back up towards their faces. He intended to make more than just his prototype. I've not seen anything on it since, but who knows it might still be available. As I recall he was asking some where between $350 and 400 for this device. I'm sorry, but I can't remember which forum it was on - TM or TMC.
     
  8. supratachophobia

    supratachophobia Active Member

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    I also recall that. If I remember, it never actually went into production or it was eclipsed by the dryer vent idea guy. Those solutions we creative, but ultimately, losing a seat and spending 400 bucks wasn't the route I particularly wanted to go.

    By using the speaker mounts holes, it's almost a completely non destructive option with the exception of needing a new speaker grill cover if you want turned turn back to completely stock. And being able to control from the touch screen is the real magic here. I honestly think if the AC air from the cabin can make it back, that will be enough. But if it isn't, those same 40mm fans can be used for the peltier radiator since it needs to be far enough away from the plates so as to dissapate the heat as much as possible possible. Which, if you read about them, this solution has the potential of getting close to freezing air into the kids faces. And actually hot air in the winter if the plates are reversed!
     
  9. tomp

    tomp Member

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    This is great - thanks for sharing!! Can you provide info about recommended fans to use? Also, can you provide more info on where you accessed the defroster power, and what type of adapters are needed?
     
  10. Bheuring

    Bheuring Member

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    I have the upgraded sound system but I still would love a Version of this also would love USB ports and the camera.
     
  11. supratachophobia

    supratachophobia Active Member

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    #11 supratachophobia, Apr 23, 2017
    Last edited: Apr 23, 2017
    Will do!

    I ended up using 60mm Delta AFB0612EH fans. I spent hours on the Delta Fan site comparing different CFM/DBA combos. This fan seemed like a great compromise. I tried a 80mm tornado for testing which is the 2nd highest CFM consumer fan that is produced and it was just too loud. The 60mm Delta's are rated at 40cfm and 45dba. They are also rated at 13.8v which tells me they are probably safer for automotive use. If we remember our car audio 101, auto voltage can get as high as 14.2-4v and I have seen 14v coming from the Tesla 12v battery before. All that being said, those fans are 25mm thickness and I just ordered the 38mm Delta model that is found in the Dell Power Edge 2800 servers. They have about 40% more CFM but only 15 more DBA. I am doubtful the extra noise will be worth it but I'm still going to test. I don't think anything thicker will work regardless, and I'm slightly dubious this 38mm will fit as nicely as the 25mm with no modification. Again, this is mainly just to get that air circulating and possibly bringing it back by force from the main cabin. For stage 2, I'm using HP pro liant 40mm fans. They are rated at 11k rpm so they sound like a freaking jet engine taking off, but I'll just run then at 5v and everyone should be happy.

    I had some Reddit users request the STL file for the bracket but I'm going to clean it up first and design in the plastic clip slots so they don't need cut by hand/Dremel.

    I'll get pics of the 12v tap, but I just stole it from before the antenna doohickey on the passenger side of the hatch and used a spade terminal with heat shrink. All nice and clean until I decide to put a switch in. I triple checked the power taps with my voltmeter and anyone else should too. I had a bit of help from another source (AAA reliable if you know what I mean) that tried to unsuccessfully explain to me some relation of the defroster and the radio antenna. Basically there is a filter device, I guess, that keeps out interference from the defroster to the radio antenna so that they can use the same filaments or be in the same vicinity to each other. Anyone who can shed more light on this, please do. The module part numbers were no help and my source had helped as much as I would allow him to.
     
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  12. supratachophobia

    supratachophobia Active Member

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    Have you downloaded Remote Camera from the play store and can you see my schosche magnet mount in those pics? That's what we use. Also, I can't see any reason you couldnt use the same 12v tap for USB ports. Again, it's 30amps, that's a lot of juice for 12v needs. The only downside is that it would be a "switched" circuit meaning you'd need to remember to turn it on when needed.
     
  13. Bheuring

    Bheuring Member

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    I don't have app will look for it in iTunes.
    What does the remote camera app do ?
    And what is schosche
     
  14. supratachophobia

    supratachophobia Active Member

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    Remote Camera runs either the front or rear camera in the background with a Bluetooth server. Then you use another phone as a client and you can watch the video live. But you can also use the phone normally while the server is running. So we put a video on the screen and check in on the kids at the same time.

    And here are the mounts. They are the best, IMHO.
    Magnet Mounts:
    Amazon.com: Scosche MAGDMB MagicMount Magnetic Dash Mount for Mobile Devices: Car Electronics
     
  15. supratachophobia

    supratachophobia Active Member

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    Small update, just as I secretly suspected, the rear defroster has a hard 15 min cut off per activation. Keep this in the back of your mind. Although nothing stops you from immediately reactivating.
     
  16. Bheuring

    Bheuring Member

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    That sucks theres got to be a way to by pass that.
    Also if you're looking for something really awesome and innovative. I found a product that I'm going to buy soon and try out myself a friend of mine has it in his Cadillac. it's awesome It's called navtool with this you can add up to four cameras .I would use the spare back one to see my third row. And you can also mirror your phone to the touchscreen letting you watch movies and stuff like that when you're super charging Or play games
     
  17. supratachophobia

    supratachophobia Active Member

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    Most if not all car defrosters are setup this way. I think Toyota uses a 20min timer.

    As for the NavTool, that's pretty cool. Can you use your own tablet as the main screen?

    Edit: The NavTool website has almost completely talked me out of their product by their webpage design alone....
     
  18. supratachophobia

    supratachophobia Active Member

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    Holy hell, is this thing for real? NAVTOOL INC

    They are talking about hijacking the camera input so as to display other images. I find this dubious at best, but excited to see if it really works....
     
  19. Bheuring

    Bheuring Member

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    Lol I am with you 100 percent they said it will show up on the 18 inch touch screen
     
  20. Akikiki

    Akikiki A'-Lo-HA ! y'all

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    and the 17" screen?
     

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