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Open Vehicle Monitor System (OVMS) - Technical Discussion

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In the 2.x roadsters, OVMS is powered from the main battery. The 12v battery is only used to power emergency systems.

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.
 
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.

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.
 
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.
 
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
 
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.
 
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
 
project launched to add Charging Station locations and status to OVMS using the OpenChargeMap database :smile:

Update an open App with new features | Android | iPhone | Mobile Phone | User Interface / IA

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.
 
I should start adding stations again :D
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:
 
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.