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Any problem with two HPWC Power Sharing to charge Roadster with CAN Sr?

Discussion in 'Roadster 2008-2012' started by pwwojcik, Jul 31, 2019.

  1. pwwojcik

    pwwojcik Member

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    Hi!

    I am pretty sure this will work but I thought that I would throw it out to the group in case anyone has experience one way or the other.

    Right now I have a single HPWC that I use to charge either my Model S and my Roadster 1.5. I am thinking about adding a second HPWC to the same circuit in the "Power Sharing" configuration. Because I am running off a sub-panel I can't really add another circuit. I assume the dual HPWC was really designed for two Model S (or X or 3). Does anyone know any reason that this would not work well for the Roadster using the awesome CAN Sr?

    Thanks!
    Paul
     
  2. X.l.r.8

    X.l.r.8 Supporting Member

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  3. Peter.h

    Peter.h Electric Newbie

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    I don't see how it would be an issue
     
  4. Curt

    Curt Roadster Signature #55

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    I’ve experienced this a few times. It seems to work just fine. It may be disconcerting if you are using OVMS.

    If the Roadster is already charging and the second vehicle plugs in on the other HPWC, you will get notices that charging has been interrupted. It always seems to restart shortly after at the new amperage, though, so it’s really not a problem.
     
  5. hcsharp

    hcsharp Active Member

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    It works great on a load-sharing HPWC (now called TWC). It will fault when you first plug it in but if you leave it alone it will clear after a few seconds and start charging. The Roadster is good at raising and lowering the amperage.

    That's interesting I haven't seen that behavior. My car has always responded normally to the change in amperage, whether up or down, without any interruptions in charging. I'll do some more testing.
     
  6. pwwojcik

    pwwojcik Member

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    This is perfect. Thanks everyone!

    And thanks again, @hcsharp , for the CAN devices!
     
  7. Frisco-Dad

    Frisco-Dad Member

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    #7 Frisco-Dad, Aug 2, 2019
    Last edited: Aug 2, 2019
    I see a similar behavior. If the roadster is charging and a 2nd vehicle (Model S) plugs in to the other TWC, then the Roadster will throw a fault and stop charging. The first few times this happened, I waited a few minutes, but the roadster did not start charging again. I loaned out my CAN SR, so I won't be able to test this again until next week. My overall solution is to plug in the Model S first then plug in the roadster. I've been doing this for almost 2 years now. If I leave the roadster plugged in, the next day it will try to charge again to top off the battery. This always works fine, even if the other car is charging. But if the other car plugs in and starts charging while the roadster is charging, it will stop and not start back up again. Not a big deal at that time because the roadster is mostly full and was just trying to top off the battery.

    For reference, I've got a 1.5 Roadster and a November 2015 build Model S.

    The CAN SR and the load sharing protocol are great. The only annoyance I have is the charging issue I describe above.
     
    • Informative x 2
  8. pwwojcik

    pwwojcik Member

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    Just to circle back on this in case anyone else is curious. I had the new wall connector installed so that it is the slave and the original one is the master. I only have one data point but everything works exactly as you would hope. I plugged in the roadster and it started charging at 32 amps (where the roadster is set). When I subsequently plugged in the Model S to the other wall connector, the roadster charging dropped to 20 amps (which is half of the configured power of the master wall connector. If I notice any weird behavior I'll report back.
     
  9. rudholm

    rudholm Member

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    I have the same experience. Two new HPC's sharing a 100A circuit, one charging a Roadster via CAN-SR, and one charging a Model 3. Works perfectly.
     
  10. hcsharp

    hcsharp Active Member

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    That's been my experience as well. Plugged in the Roadster first and it was charging at 40A. Then plugged in a Model 3 and the Roadster dropped to 20A but kept charging, and the Model 3 began charging at 20A. I have a 2.5.
     

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