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Dual Charger Question

Discussion in 'Model S: Battery & Charging' started by Chipper, Dec 22, 2013.

  1. Chipper

    Chipper Active Member

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    If my MS has dual chargers and I set charging off the HPWC to 40 Amps am I using both chargers at half capacity or one charger at full capacity?
     
  2. stevezzzz

    stevezzzz R;SigS;P85D;SigX

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    If a tree falls in the forest and no one is there to hear it... :wink:

    Good question! Similarly, does the second charger ever get used when the UMC is plugged into a 14-50? My car came with two chargers, but I've never charged at over 240V/40A...except at a Supercharger, which bypasses the onboard chargers.
     
  3. jerry33

    jerry33 S85 - VIN:P05130 - 3/2/13

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    One is a master and one is secondary. If the master is down neither will charge. The way to determine this is to check the temperature of each after an hour or more of charging. The problem is that the rear seat is very hard to get back in once removed (according to the Ranger). If you can borrow a thermal imager it shouldn't be necessary to remove the seat.
     
  4. lolachampcar

    lolachampcar Active Member

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    jerry,
    Always well thought out solutions.
     
  5. brianman

    brianman Burrito Founder

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    From what I have seen, my impression is that if your max amperage is set at or below 40 A then only the master is used. At 50A, it appears to use 25A/ea for master and slave. I haven't tested 41-49A.

    This based on seeing the amperage rampup "stall" at the halfway point of the max amperage in the range [50,80]. My interpretation is that this stall is the wakeup+negotiation with the slave charger.

    Just an impression. Could be totally wrong.
     
  6. lloyds

    lloyds Member

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    This is my impression as well. Glad I have it for those who are considering twin chg
     
  7. Chipper

    Chipper Active Member

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    Thanks to all who provided answers. Greatly appreciated. As a result, I think I will always charge at about 50 Amps.
     

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