Not charging at 48 amp

[isjka]

Hi,

I’ve been seeing some strange behavior with my home charging using the HPWC. I have a S 70 with 48 amp onboard. As you can see the first times I charged the vehicle, I was charging at 48 amps almost consistently. The last charges though have all been close to 46 amps. Is this normal? The only thing I can think of that has changed since receiving the 48 amps, would be the weather and a recent power outage. However, I’m not sure if those events correlate to the lower amperage. Another interesting data point, yesterday when I first plugged the car in it showed 46 amps. I went to the cable and sort of loosened some kinks and then reseated the cable in the charge port. The car then showed 48 amps. It then charged overnight at the 46 amps. Any ideas as to what could be occurring?


Thanks.

 

[scottm]

Yes, I see it.

Thanks for all the data.

When the voltage is abnormally high (much greater than 240) the car is kicking down the Amps to keep the overall power (volts times amps) consistent.

You should add an extra column to your data, and call it "power" and formula is avg volts times avg amps. It's probably pretty consistent.

Be aware too though, if the voltage starts to drop (sags much below 240) the car may kick down the Amps it is drawing because it thinks it's charging too hard and is creating the sag. So it will backs off the Amps... and when it does this the voltage may rise back up a bit. It tries to balance a "reasonable power draw" by dialing down the Amperage.

Finally, the car will never dial "up" the Amperage beyond what you've set on the console.

And you can't dial up Amperage higher than what the charging equipment is configured to allow (by virtue of what adapter head is installed on the UMC, or what the HPWC is configured to deliver).

 

[mongo]

Hi,

I’ve been seeing some strange behavior with my home charging using the HPWC. I have a S 70 with 48 amp onboard. As you can see the first times I charged the vehicle, I was charging at 48 amps almost consistently. The last charges though have all been close to 46 amps. Is this normal? The only thing I can think of that has changed since receiving the 48 amps, would be the weather and a recent power outage. However, I’m not sure if those events correlate to the lower amperage. Another interesting data point, yesterday when I first plugged the car in it showed 46 amps. I went to the cable and sort of loosened some kinks and then reseated the cable in the charge port. The car then showed 48 amps. It then charged overnight at the 46 amps. Any ideas as to what could be occurring?


Thanks.

View attachment 275761

The supply voltage went up almost 10 volts. As a result, it dropped the current draw. The total power stayed the same.
244.27*47.03 = 11.49 kW
250.4*45.75 = 11.45 kW

Rated
240*48 = 11.52 kW

@scottm Yep, was typing already when you posted

 

[isjka]

Excellent explanations and very useful data. So basically there is nothing to worry about it seems. Wanted to make sure that nothing out of the ordinary on the car, or with my electric, was the root cause.

 

[mongo]

Excellent explanations and very useful data. So basically there is nothing to worry about it seems. Wanted to make sure that nothing out of the ordinary on the car, or with my electric, was the root cause.

Always good to check. The other possibility was that your supply voltage was drooping and the car reduced draw to protect your wiring.

 

[Snowstorm]

It is strange that you got a 250v supply

 

[mongo]

It is strange that you got a 250v supply

That is only 5% high during winter post Chirstmas lights. In the summer with AC loads going, it will likely droop some. Of course, depends on gas vs electric heat too.
The recent power outage may have caused the power company to replace the weakest/ lossiest link in the area which bumped things up slightly. May also be hysteresis at a voltage adjusting transformer.