Model S Signature Charging Slowly

[Gu$ G]

We noticed today that our '12 Signature Model S is suddenly charging slower. I'm wondering if this is a software limitation that Tesla just implemented.

The car is a P85 with the high amperage charger. I have a wall connector installed for the last 2 months or so. I charge at only 20 amps overnight. Today, we noticed I'm only getting 10 mph at 20A and 16 mph at 30A. Of course I can turn up the amperage with the wall connector, but my house has a limited electrical load and I try to charge the car slowly.

The wall connector guide shows the rate of charge should be about 50% higher...

I'm just trying to see if this might be part of all the safety changes Tesla has been accused of implementing for these older batteries. I'm on the original battery and would love a replacement...

Any thoughts?

 

[ucmndd]

Are you sitting in the car with the AC on and accessories running while observing this? If so the amount of energy added to the battery will be lower.

Miles per hour is a terrible way to measure charge speed. The only thing that matters is voltage and amperage.

What is the reported voltage and power while you’re charging?

 

[maximizese]

Just curious but if you look on the Tesla app or the MCU while charging, how many volts do you see? You might be charging at 20A and only getting 200V resulting at a 4kW rate. Generally I charge at 32A and see the voltage between 230-237V 24mi/h implying a 7.58kW rate on our S85. The Juicebox can go up to 75A, but eMotorwerks told me the charging plug can handle no more than 40A...besides, I haven't needed to charge any faster than 32A overnight.

 

[Gu$ G]

As an update, I found that this was an electrical problem with our wall connector installed. We added a new breaker box to service the garage. The main line neutral was loose. Tightened it and the problem is supposed.

I never saw what voltage I was seeing via the app or in the car. I imagine it was something off...

Car is charging great now!

 

[whitex]

As an update, I found that this was an electrical problem with our wall connector installed. We added a new breaker box to service the garage. The main line neutral was loose. Tightened it and the problem is supposed.

I never saw what voltage I was seeing via the app or in the car. I imagine it was something off...

Car is charging great now!

That is really weird, because the HPWC/wall connector doesn't use the neutral wire at all (no place to even connect it).

 

[Sairaph]

I had a similar issue earlier this year. It was the charging cable that comes with the car so I went to the local shop and bought a new cable.