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Losing Full Charge Ability -Home Wall Charger

Discussion in 'Model S' started by craigwatson, Dec 6, 2019.

  1. craigwatson

    craigwatson Member

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    Two days ago I received the prompt to upgrade to 2019.36.2.4 and as all good Tesla geeks do I did the upgrade as soon as possible. One problem though....
    Ever since the upgrade when I charge via my in-home wall charger I am only able to charge at up to 30mps/7kW... My home charger has only charged at 40Amps/10kW
    Yesterday it was only able to charge at 30/30A and right now is charging at 30/40A... I am currently at a 75% SoC do this is weird

    Anyone else experiencing degraded charging?
     
  2. whitex

    whitex Well-Known Member

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    Are you saying that your car recognizes you home charger as a 30A charger one day and as a 40A charger on another day? What charger are you using (and how old is it)?
     
  3. craigwatson

    craigwatson Member

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    Yesterday the app showed it charging at 30/30 and I am assuming it means it was only thinking it was a 30amp charger

    Today it was charging at 30/40 so seeing it as a 40amp charger but only charging at a 39 amp rate

    I am using my Tesla Wall Charger which through two Teslas has always read at 40amps

    any thoughts or should I assume it’s a firmware issue since it coincided with the car update?
     
  4. craigwatson

    craigwatson Member

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    The Tesla Wall Charger was bought with my first model S in 2017.... now charging a 19 Raven S
     
  5. whitex

    whitex Well-Known Member

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    Is the wall charger Gen1 or Gen2 (Gen2 has a built in charge handle hanger)? We had a Gen1 wall charger which successfully charged a 2015 and 2017 Model S, but when we connected a 2018 Model S to it, we started kept getting weird intermittent charging errors - apparently they are not 100% backwards compatible (you can find threads on this on TMC). Tesla gave us a new Gen2 wall charger to charge the 2018 - I still had to take care of installation, but at least didn't have to pay for new charger for new Tesla. This was back in early 2018 though so before the Model 3 flood and Elon's austerity measures.
     
  6. Rogue Synapse

    Rogue Synapse Member

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    Have you checked whether you can manually reset the maximum amperage of that particular charger? On the charging screen it usually does that for you, but you can set a different max charge rate manually and it’s geo-sensitive and remembers your selection for next time. There’s a 110v outlet in my garage that apparently shares a circuit with something else and I have to manually dial down the amps if I want to stop the breaker from tripping (this is with my UMC though).

    I’m not saying you dialed it down to 30, but try seeing if it will let you dial it up to 40 on the charging screen on the MCU.
     
  7. whitex

    whitex Well-Known Member

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    @craigwatson , I forgot to ask the basic diagnostic question, did you reset BOTH the car and the wall charger (use the breaker to power cycle it)?
     
  8. craigwatson

    craigwatson Member

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    It’s a Gen 1... weird that it has been fine until the update... I’ve power cycled the car but need to cycle the charger... will do and see if that works
     
  9. BigNick

    BigNick Disaffected Member

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    If the charging voltage drops below a certain threshold or percentage while charging, the car will reduce amperage by about 25% for safety.
    At my work location there are two "30A" public chargers which run on 208V, but when pulling 30A the voltage sags to around 195V and this kicks in the safety protocol, dropping my charge to 22A. (I have sat in the car while charging and watched it happen).
    I usually charge at home, 40A on a 240V circuit that was run for 100A peak/80A continuous draw, and the car has never dropped below 40A except when above 90% SoC (normal charge taper).

    I am still on 2019.32.12.7. The drop may be due to a software bug, or the voltage sensitivity has been changed in the newer software.
    Or your electric supply could have been experiencing a brownout or power fluctuation that caused the amps to drop.
     

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