Why are the expected charging times way off on 120v charges?

[Zacster]

I plugged my car into a wall outlet and I see it is charging at 6mph as expected. I can see the range increase at that rate as well, so no problems there. What I don't understand is the remaining time calculation. I'm at 194mi right now, have it set to 90% or 236 miles, so that should be 7 hours, but it is saying 21 hours. Even if the charging slows down as it nears capacity it still shouldn't take 21 hours. When I used a supercharger recently it said a half an hour and it took a half an hour.

 

[Mrbrock]

Post a picture? Maybe a scheduling issue? Or temperature?

 

[Zacster]

Since I wrote this it self corrected and now says 4h 10m. Temps were in the low 40s, and I have no scheduling set up. Go figure.

 

[Mrbrock]

It may have been using the power to run your climate control so no power was going into the battery. If you are in the car or door is open it will be running climate and radio and will use plug power when available. When you are on SC, there is so much more power available that it doesn’t affect your charge time. On 110V, it uses a significant amount if not all.

 

[Zacster]

No. The car was parked and locked. Everything was off. In any case after driving around today I plugged it in again and the time was within normal range.

 

[Mrbrock]

So the car was parked for a while before you plugged it in initially? At 40F you probably had cold soak and the battery heater running before it started charging.

 

[Sklith]

If the car's battery is cold, it'll switch the available power over from charging to warming it up. It's not good at estimating how long it'll take to charge when it's switching between heating and charging at low power.

 

[Zacster]

Cold battery is probably what it is. Since I first posted I've plugged it in a few times and when it was cold it would read wrong.

 

[Mrbrock]

Yep. Car is directing the energy from the plug to heat the battery so the bms is only seeing a very low amperage and is using that to calculate time needed. Typical operation but not mentioned in the manual afaik.

 

[Gasaraki]

Every little thing can pull a few hundred watts that throws off the speed because it's so low.

 

[Zacster]

While I understand now what is happening, having the time remaining recalculated is pretty trivial for the app to do. I just plugged it in and it is cold so I'm seeing 0 mi/hr, I'm watching to see how long it takes for the battery to warm up to take the charge. It is 39F outside, not that cold.

OK, 10 minutes after I posted this it started charging at 6mi/hr, what I usually see. And when it says 6mi it means 6mi. I'm doing my first full charge since I'm planning a long round trip tomorrow that should be just over 200 miles. There are superchargers along the way, and probably a destination charger where I'm going, but I just want to see how this works out.