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Open Vehicle Monitor System (OVMS) - Technical Discussion

Discussion in 'Roadster: Technical' started by markwj, Nov 1, 2011.

  1. markwj

    markwj Moderator, Asia Pacific

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    Thanks for the update. Blame the Gremlins?
     
  2. smorgasbord

    smorgasbord Active Member

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    I wish I had taken better notes when my battery was de-fused. I think the bus OVMS sits on is part of the 12 volt circuitry. That circuitry is powered either by the main battery, when the car is "on" - or via the 12 volt battery when the car is off. Without the 12 volt battery I was still able to open the car doors by opening the trunk or charge port door first. OVMS would work while the car was running, and for about 15 minutes afterwards. If the car was plugged in, OVMS seemed to work. Now I wish I had notes about whether locking the doors via OVMS worked without the 12v battery with the car plugged in. I don't believe it did.
     
  3. markwj

    markwj Moderator, Asia Pacific

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    I can say with 100% certainty that OVMS cannot be powered by just that 12V battery. If the main traction battery fails (and hence it's 12V converter), there will be no power to the VMS, VDS or OVMS. Emergency components like brake lights, hazard warning lights, etc, will continue to work off the little 12V battery. That is the primary purpose of the little 12V battery (to provide power for emergency components in the event the main traction battery fails).

    The other way round (little 12V battery dead, main traction battery ok, but can't unlock doors); I am told the reason is because the door lock/unlock uses the 12V battery by design, if the car is asleep. Waking up the car (opening the trunk or charge port door first, or just pressing a door handle) will allow it to use the 12v converter from the traction battery. You can hear if the car is 'awake' because the coolant pump is working.

    So, where does the 12V on the DIAG plug that OVMS connects to get it's power from? I suspect an always-on 12V converter in the main traction battery - and the same power supply that goes to the VMS and VDS. The CAN bus in the Tesla Roadster is always on (even when the car is asleep) and the VMS is a relatively power hungry Linux computer - it would drain that little 12V battery in a matter of hours.
     
  4. smorgasbord

    smorgasbord Active Member

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    Thanks, Mark. Makes sense and nothing I saw with a disconnected battery would contradict that.
     
  5. markwj

    markwj Moderator, Asia Pacific

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    Not sure if you guys had seen this diagram:

    Firmware-Processors_diagramER.png

    It shows the 3 main CAN buses (power, energy and driver). OVMS hooks in to the "DRIVER FEEDBACK" bus.
     
  6. mg012

    mg012 Member

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    Mark,
    Where would I see the battery heating info on the OVMS app? I've looked at it during some very cold morning (35 degrees F) and not noticed anything new. Does that only occur if the car is plugged in (because it wasn't)?
    btw: I love the app. Please don't interpret these questions or requests as anything negative.
    thanks
    michael
     
  7. PV-EV

    PV-EV Member

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    mg012- battery heating depends on the temperature of the battery and not ambient. It is a pre condition to charging that the car will perform automatically if needed. As it is a part of charging, the car must be plugged in. The charge port flashes blue when heating and the app says "charging/heating" and also reports the amp draw. These are displayed in the same place as normal charging.

    Hope that helps

    Jack

    BTW I've seen ambient temperatures near 0 F and the car not go into heating if we have just come back from a drive.
     
  8. vcor

    vcor Member

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    Great diagram. Do you know if we can interpret it to mean each box has a processor of some sort? Also is this for the Roadster or the Model S?
     
  9. markwj

    markwj Moderator, Asia Pacific

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    Yes, that is a processor diagram. It is for the Roadster.
     
  10. mg012

    mg012 Member

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    PV-EV and Mark
    thank you very much for all this info. I have only owned my roadster about 3 months and just reread all the manuals. This is additional, helpful information which makes the ownership even more fun. Its great to know more about what its doing when it looks like its not doing anything. What the Tesla lacks in moving parts it makes up for with technology and software. I love the evolution.
    Michael
     
  11. Kevin Sharpe

    Kevin Sharpe Active Member

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  12. markwj

    markwj Moderator, Asia Pacific

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    Kevin: Thanks for helping out with this - such integration could be amazingly useful.

    Users: A short summary is that we're trying to integrate live range to the OVMS car location map, and to show all charging stations within range. Clicking on a station will bring up further detail. Once that basic work is done, we're planning to look at how we can integrate the charging events, correlated with OCM charger location, to feedback charge results (both good and bad) to OCM.

    There is a requirements spec at the link Kevin provided, with more detail.
     
  13. jcstp

    jcstp Active Member

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    WOW
    I should start adding stations again :D
     
  14. Kevin Sharpe

    Kevin Sharpe Active Member

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    maybe no need in future.... imagine OVMS automatically reports to OCM your location, voltage, current, time, etc., every time you charge at a public Charging Station.... suddenly OCM is always up to date and the data can be used by any EV running an OCM app (or any EV manufacturer who uses the OCM data in it's navigation system). Imagine you have found a way to bypass all the charging vendors who don't want to share their data :tongue:
     
  15. VolkerP

    VolkerP EU Model S P-37

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    Hi Kevin,

    great! I want to see this idea get real.
    Please include an interface to add data to every charging location that (as of today) only a human can enter:
    - public / private access: permission necessary?
    - opening times

    We discussed this back in 2011 (Robert.Bostin, DHrivnak et. al.) in case you need to refer to some names :rolleyes:

    Charging stations + parking garages = :) | Forums | Tesla Motors
     
  16. Kevin Sharpe

    Kevin Sharpe Active Member

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    This IS real and the OVMS development will start this week. I've already sold the idea to several EV manufacturers and will raise it at the ministerial roundtable meeting on the 4th March :smile:
     
  17. Kevin Sharpe

    Kevin Sharpe Active Member

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    Integration with the OpenChargeMap Charging Station database is making good progress...

    IMG_2248.PNG
     
  18. markwj

    markwj Moderator, Asia Pacific

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    The approach of grouping charge stations into numbers-in-circles, at zoom-out levels, works really well. Also, very scalable as the number of charge stations increases. Congrats to whoever designed that.
     
  19. markwj

    markwj Moderator, Asia Pacific

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    Working with the guys at zerocarbonworld / openchargemap on the integration of Open Charge Map to the OVMS Apps, we are trying to find a way to represent range graphically.

    The first idea was a circle, centered around the car, with the inner edge of the circle being estimated range and the outer edge ideal range (or vice versa if you are coming down the mountains on a _long_ mountain road). Plugging in the values for my car today, assuming I was somewhere in the centre of the UK, it would look something like this:

    PastedGraphic-4.png

    The idea is to represent the range, and then plot the charge points within (and perhaps also slightly outside) that range.

    (There should be an icon representing your car (at the centre of the circle), but I didn't add it to the prototype picture shown above.)

    That is just one idea. What do people think? Any other suggestions?

    Regards, Mark.

    P.S. Work on the Apps for this has already started, so I would appreciate a quick reply. Nothing too extensive - just ideas. Thanks.
     
  20. mg012

    mg012 Member

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    Looks fantastic!
     

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