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Help Problem with HPWC

Discussion in 'Model S: Battery & Charging' started by cmorn, Jul 29, 2014.

  1. cmorn

    cmorn Member

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    Location:
    Atlanta, Georgia
    Had a problem charging the last two nights. Chances are that I will need to try some other things to figure out the problem, but I just thought I would ask for some suggestions on what the problem might be. Sorry that I don't have complete data, but here is what I have. I charged Sunday night after a road trip where I supercharged 4 times. I changed my charge level back down to about 70%. I didn't look at the dash or the port on Monday morning, so I don't remember if there was an error. However, when I got home Monday evening, there was no power in the HPWC. The breaker had tripped. I reset it and all seemed well. This morning, the charge stopped early (after 40 miles added), and there was an error on the dash - unable to charge. I'm not sure if the breaker tripped again or not. Any ideas?

    Chuck
     
  2. Cottonwood

    Cottonwood Roadster#433, Model S#S37

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    When breakers trip, it is usually for a reason. That reason needs to be corrected. What is the size of the breaker? What current is your car charging at on the HPWC? The car should be charging at a current that is 80% or less of the breaker rating. There are dip switches inside the HPWC that should be set to the size of your breaker to make this all work.

    Whether the breaker has tripped or not is important info. If the breaker box is a long way away, you can get indirect info of power to the HPWC by lights on it, and the Voltage reading inside the MS.
     
  3. cmorn

    cmorn Member

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    This HPWC has bee in use for about 5 months with no previous problem. The Circuit is 100A and the dip switches are set for 80A. Car also set at 80A.
     
  4. pgiralt

    pgiralt Active Member

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    I agree with Cottonwood's assessment. A breaker trips for a reason and just resetting it and hoping it doesn't happen again is generally not a good idea unless you understand why it tripped in the first place. When you you plug in to charge, what is the voltage shown before the charging starts (when it's showing 0A/80A) and then what is the voltage when it ramps up to 80A?
     
  5. Cottonwood

    Cottonwood Roadster#433, Model S#S37

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    Is it really hot where the circuit breaker is located? Most, typical circuit breakers have two trip mechanisms, magnetic and thermal. The magnetic mechanism trips on high current very quickly. The thermal mechinism trips on marginally high current over some time, 30 minutes or more. If the ambient temperature is higher, the thermal mechinism becomes more sensitive.

    If someone that is competent and comfortable taking the cover off of the breaker box can put a clamp-on current meter on the wires going coming out of the 100 Amp breaker going to the HPWC, you can check that the current is correct, and there are no other paths allowing increased current through the breaker.

    If you can't find any other issues, try dialing the current limit in the car back to 60 Amps and see what happens. If the breaker does not trip at 60 Amps, then at least you can still charge your car, just a little slower.

    Sometimes, a breaker that has tripped many times becomes more sensitive, worn out. You could have a worn out breaker, or an overly sensitive breaker. In that case, the solution is to replace the breaker.
     
  6. cmorn

    cmorn Member

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    Location:
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    Thanks. I will check the voltage, and then reduce the amperage to 60 when I charge tonight.
     
  7. cmorn

    cmorn Member

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    Charging now on UMC @ 110. No problems. I will start the HPWC at 7pm when the rate goes down.
     
  8. cmorn

    cmorn Member

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    I charged for 2 hours @ 110/12 with no problem. Then I plugged in the HPWC. Started at 242V, when it got to 80A it was at 237V. The breaker tripped in about 30 minutes. I set the amps down to 60 in the car, and the charge completed. The breaker switch felt a bit warm right after it tripped. I will have my electrician look at it.
     
  9. Cottonwood

    Cottonwood Roadster#433, Model S#S37

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    If you got 30 minutes before tripping, and with only a 5 Volt drop at 80 Amps, it sounds like you have an overly sensitive breaker. You could probably charge at 70 Amps, but given that you have a temporary charging solution, is it worth finding the threshold? Ask the electrician to put a clamp-on ammeter on the wires out of the breaker to make sure that the current out of the breaker matches the current into the car.

    Good Luck!
     
  10. Lloyd

    Lloyd Active Member

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    Sounds like the connections at the breaker need to be checked and re-torqued.
     
  11. FlasherZ

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

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    Yes, that's where I'd go too, Lloyd. Check for loose connections, torque them again, then replace the breaker. Breakers do go bad, and some (rarely) are bad right out of the box.
     

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