Did you resolve this? I have the same symptom.
My 2020 Model 3 has been doing this too about 50% of the time for about 2 months now. I have a scheduled charge starting at 00:30 at the usual 32A, but sometimes I find it's still charging many hours later at 5A. I've had the car since April 2020, and this started happening around May 2022. No changes to home charging setup or anything else electrical at home in this time.
Luckily, I have Teslamate running at home on a Raspberry Pi. This gives very good charging logs, including voltage during charges. They show the problem happening at around 02:00, with the charge rate dropping from 7kW to far lower - around 1kW. This coincides precisely with an instantaneous voltage increase, from around 230V to 240V. This higher voltage then continues for the remainder of the charge period.
What I don't know is where the cause and effect is here; all I have is a correlation. I've yet to find a voltage recorder that I can leave running overnight so I can see if the voltage change happens without the car being connected. Frustratingly, my local grid supplier (Western Power) are not interested - they insist such a voltage jump is within supply tolerance, and they're right. I'm guessing the car is being overprotective and reducing charge rate, so what I'd like to understand is whether this is a fault or just by design.
There is a section in the Tesla manual that says this:
"If Model 3 is charging and detects unexpected fluctuations in input power, the charging current is automatically reduced by 25%". I guess this could be what is happening, but it's not a 25% drop - it's a 70% drop. And these fluctuations should not be unexpected, being within standard UK supply tolerance.
Have yet to try this with another Tesla. May come to that!
My 2020 Model 3 has been doing this too about 50% of the time for about 2 months now. I have a scheduled charge starting at 00:30 at the usual 32A, but sometimes I find it's still charging many hours later at 5A. I've had the car since April 2020, and this started happening around May 2022. No changes to home charging setup or anything else electrical at home in this time.
Luckily, I have Teslamate running at home on a Raspberry Pi. This gives very good charging logs, including voltage during charges. They show the problem happening at around 02:00, with the charge rate dropping from 7kW to far lower - around 1kW. This coincides precisely with an instantaneous voltage increase, from around 230V to 240V. This higher voltage then continues for the remainder of the charge period.
What I don't know is where the cause and effect is here; all I have is a correlation. I've yet to find a voltage recorder that I can leave running overnight so I can see if the voltage change happens without the car being connected. Frustratingly, my local grid supplier (Western Power) are not interested - they insist such a voltage jump is within supply tolerance, and they're right. I'm guessing the car is being overprotective and reducing charge rate, so what I'd like to understand is whether this is a fault or just by design.
There is a section in the Tesla manual that says this:
"If Model 3 is charging and detects unexpected fluctuations in input power, the charging current is automatically reduced by 25%". I guess this could be what is happening, but it's not a 25% drop - it's a 70% drop. And these fluctuations should not be unexpected, being within standard UK supply tolerance.
Have yet to try this with another Tesla. May come to that!
