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Is the MS AC charger true 3 phase or 3x single phase chargers?

Discussion in 'Model S: Battery & Charging' started by thegruf, Jan 24, 2016.

  1. thegruf

    thegruf Member

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    Hi, sorry if this has been discussed before, I couldn't get an answer through the search.

    (also if they are different from NA; I am talking about 230V UK spec chargers)

    If a single charger is good for 11KW (3 phase) and I am charging at 32A single phase (32 x 230 = 7.4KW) ,
    I'm not sure I understand how this can be, and I am curious how it is connected.
     
  2. LuckyLuke

    LuckyLuke Model S P85DL

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    From what I have read on this forum is that gen2 EU chargers are actually 3 separate chargers but they can be bridged internally to take 32A single phase.
     
  3. thegruf

    thegruf Member

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    Just checked the Blue UMC adapter and yes the live is commoned to three pins which seems to confirm bridging.

    maths at 32A single phase still doesnt seem right to me.
    I'm guessing the the UMC cable is 5 core, 16A rated one for each phase and two for neutral limiting the cable to 32A max whereas I would expect the charger itself ccould take more, maybe up to 48A.
     
  4. FlasherZ

    FlasherZ Sig Model S + Sig Model X + Model 3 Resv

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    The GEN2 chargers are good for 16A per phase; so dual chargers are good for 32A per phase with appropriate EVSE. They use a common neutral and 3 individual line inputs. As noted, for > 16A on single-phase they bridge to an additional line conductor.

    The problem with taking a single-phase and bridging across the inputs is that in three-phase scenarios, the neutral only carries the imbalance of load between the phases; when you're bridging the line conductor of a single-phase input to a three-phase input, all current returns via the neutral and therefore needs to be able to handle the total single-phase current. So the neutral would need to be able to carry 96A if all three phase conductors on dual chargers were fed with 32A.
     
  5. thegruf

    thegruf Member

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    ^ interesting - confirms my thinking to some extent assuming you are talking about the 230V spec chargers here.

    So if a single charger is fitted, and can cope with 16A per phase, then if the blue adapter bridges all three phases (it does I checked it) then in theory you could charge at 48A total ... providing the Neutral is rated to cope with this.
    Hence my guess that this is cable limited.

    which if true would be a big pity that for the sake of a bigger cable users on single phase supplies could charge at the full 11KW.

    There is probably also the point that pulling a constant ~50A on a domestic supply might not be the best idea although there are electric showers readily available that pull almost as much as this
     
  6. tom66

    tom66 Member

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    EU chargers are 11kW rated so 48A doesn't sound too far off.

    The Gen2 chargers for US models are three phase, the same as the supercharger ones, but all three phases are internally commoned.
     

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