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Is the battery post under the nose cone fused?

Discussion in 'Model S: Battery & Charging' started by artsci, Jun 3, 2014.

  1. artsci

    artsci Sponsor

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    #1 artsci, Jun 3, 2014
    Last edited: Jun 3, 2014
    I installed a Wagan Smart AC 400 watt, 2.1 amp inverter in the nose cone today. It has two 120V outlets and 2 USB ports. Photos below. It's powered from the battery post under the nosecone. I plugged in and sucessfully tested several 120V devices. But when I plugged in a 12v power supply to do another test of the rear lighted T, it beeped and shut down. The beep indicates insufficient 12v power and in those instances the Wagan shuts down. I tested the the power output of the 12v battery post and there's no power, so I assume it's fused. I won't have time to check the fuse box until tomorrow so I'd thought I'd ask. Is it fused?

    BTW, the 12v battery is working fine -- the car starts as normal and all of the 12v powered accessories power up as they should. That leads me to believe that the post under the nose cone is fused. The red thing in the photo below is the post i'm talking about. The little red vinyl boot is removed and power is accessed by making a connection to the bolt under it.

    NoseCone1.jpg

    Here are photos of the Wagan installed in the frunk.

    _DSC4893.jpg

    _DSC4894.jpg
     
  2. Madartist

    Madartist Member

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    That's amazing work, as usual. What are you planning to plug into it?
     
  3. artsci

    artsci Sponsor

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    Thanks but I can't take credit for the idea. I learned about this by seeing another owner who did it to his car and recommended the Wagan to me.

    As I do much of my work on the car outdoors I'll use it to power tools such as soldering pencils, drills. etc. Now and then I may hook up a vacuum. Will also use the USB ports to charge iPads and the like.

    But back to the question. Is that connection fused? I'm thinking it must be or why isn't it putting out any power?
     
  4. siai47

    siai47 Member

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    Someone on another thread about the 12 volt DC converter said the front post is fused with a 50 amp fuse but didn't say where it is located.
     
  5. artsci

    artsci Sponsor

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    Thanks. I'm going to check the fuses this morning and report back what I find.
     
  6. yobigd20

    yobigd20 Well-Known Member

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    where did you buy the outlet from? online? link ?

    when I bought the car, I assumed because of all the ridiculous amount of power in there that there would be at least one 120V outlet. I was surprised to find there weren't any. This is something I'd be interested in doing myself too.
     
  7. artsci

    artsci Sponsor

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    You can find it on Amazon.

    - - - Updated - - -

    There is no 50 amp fuse in this car, at least among all the fuses listed in the owner's manual. I checked all of the fuses that could possibly protect this circuit but they were all ok. So I've sent an email to my SC to see if they can identify the fuse or confirm that the circuit is fused in the first place.
     
  8. Kalud

    Kalud Member

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    I am the one who claimed this. I didn't check myself yet, but I specifically asked an experienced ranger how those posts are hooked up and he said they goes directly to the 12V battery through a 50A fuse (no diode). I should have asked where the fuse was located... You probably blew the fuse. 12V*50A means 600W, your inverter is 400W but 1000W peak, maybe you've exceeded the fuse's rating longer enough to blew it.

    Once you've located the fuse please let us know!
     
  9. mknox

    mknox Well-Known Member

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    It might be an in-line fusible link.
     
  10. pgiralt

    pgiralt Active Member

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    Yes, I believe there is a fuse, but I'm pretty sure the fuse is actually sitting on top of the battery. Let me see if I can find the photo I saw a while back that showed this...

    - - - Updated - - -

    Found it here:

    http://www.teslamotorsclub.com/showthread.php/10349-12-V-battery-pictures

    Battery closeup.jpg

    Would be interested in hearing what kinds of fuses those are and how hard it is to get to them to replace them.
     
  11. green1

    green1 Active Member

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    I think you may be in for some disappointment, 400W is not enough for most soldering irons, and is probably pretty marginal for vacuums and drills. You're talking some high current accessories, and a low current inverter. For serious power use I'd recommend no less than 1000w inverter, that's still less than a standard household outlet. I'd also connect directly at the DC-DC converter, not via other cables. (keep in mind that 1000w is 83 amps at 12v, so I'd use a 100A fuse and some heavy duty wiring)
     
  12. mknox

    mknox Well-Known Member

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    What about connecting directly to the 12v battery terminals, with appropriately sized fusing of course. This is typically how it's done on an ICE vehicle for large current accessories.
     
  13. artsci

    artsci Sponsor

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    The wattage ratings for the devices I use will not be a problem. Considered that before buying the Wagan.

    Thanks for the photo Pgiralt. I'll look for the fuse on the battery top.
     
  14. wk057

    wk057 Senior Tinkerer

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    Does anyone know the rating of the DC-DC converter on the Model S? And the potential headroom with existing draws? I looked around for this info before, briefly, but never found any real answer.

    I was looking into adding an inverter before, but without knowing how the DC-DC would react to a decent load (~100A @ 12V or so) I wouldn't want to do so.

    Would be nice if there were high voltage DC-AC inverters available with higher current outputs (20A @ 120V, for example).
     
  15. spaceballs

    spaceballs Member

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    What type of soldering irons are you using!
    As most soldering irons are 10-100 watts.

    - - - Updated - - -


    Solar inverters.

    Not sure on Model S, but Roadster is like ~2kw max for the on board DC-DC converter, i.e. http://www.martekpower.com/products/en/ps2450.html
     
  16. Kalud

    Kalud Member

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    someone gave the exact power rating in another related thread.
     
  17. Cottonwood

    Cottonwood Roadster#433, Model S#S37

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    Here it is: Current Maximum on 12V system, 2500 Watts. This was for a more recent Model S. Apparently the older MS's have the DC to DC near the passenger side wheel well and may or may not be the same power.
     
  18. green1

    green1 Active Member

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    I was apparently mistaken, I was sure mine was 700 watt, but turns out it's only 60 watt. I must have been confusing it with the 700F temperature rating.

    I've never tried running that off an inverter, I've always used a butane soldering iron when not near mains power.
     
  19. wk057

    wk057 Senior Tinkerer

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    Problems with high input voltage solar inverters: Most are grid tie, meaning they have islanding protection that would need to be disabled. Also, not many I've seen will do ~400V input.
     
  20. GasDoc

    GasDoc Member

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    The block sitting on top, on the right side, with the Blue "C" shaped figure is the pyro fuse that blows when the airbags deploy, I believe.
     

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