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Slow (17kW) Supercharging in the cold. You?

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#23
Exactly. However, that still takes quite a bit of time. I recently did a cold weather drive in a P100D Model S and the MCU estimated that it would take 1 hour for the max battery power option to fully heat the pack (50C). Of course, 50C isn't required for full-speed supercharging, so it wouldn't take that long... still 30+ minutes from stone cold.
 
#24
Further to the above, it seems no matter how long I sit at the Supercharger, three rate of charge never seems to increase. I would think they'd warm the battery and as it warms up, increase the rate of charge. That doesn't happen though. I've sat at a charger for 45 minutes with the charge rate stuck at 17 kWh.

Anyway, when we pulled into Canmore last night we got 110 kWh and it was.-24C. This took 3 hours preheating before departing, 334 km driving and two Supercharger stops along the way before FINALLY getting the rate of charging I expected. Of course that happened just in time to stop for the night.

Interestingly, I charged to 94% then moved the car and went to bed. When I awoke, I put the car back on the Supercharger to charge to 100% and warm the car while everyone showered, packed and ate breakfast. The car had 93% this morning. It was -24C when I moved the car before bed and -23C when I plugged it in. What vampire drain? Maybe it's too cold for vampires?!
 
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#25
Rocky_H said:
No & Yes. Sure, they could use better set points or control, but I disagree wholeheartedly in your statement that you don't think the heating method is also a big problem. It really is less effective at generating much heat quickly.

So there you go--the method of heating is the problem.

Heh, you left out the main factor of what they were trying to strike a balance between. They were trying to go cheaper. I'm sure they knew that the Model 3 heating methods were going to be less effective, but probably thought it was good enough. And sometimes for some people in some temperatures, it is, but in other cold places, it isn't.

I'm pretty certain it is already doing that. While it's sitting on a Supercharger and has access to virtually unlimited power levels, that would be the time when it would be using that power to run that motor-heating-the-battery method. The fact that it takes so long for charging speeds to climb upward seems like the most clear evidence that it just doesn't generate heat as fast as the S/X battery heater.

This is something I'm still skeptical of about this method of heating with the motor. I don't know if it can do that. The method of heating using the motor needs to run current through the motor windings, and obviously it can do this when the car is parked. Keeping the motor locked and not moving can be providing extra resistance to the current in those wires because of the magnetic fields, so generating extra heat. But when the car is driving and needs to use those windings in it's particular directions and frequencies to rotate it at the speeds the driver is controlling, I am not sure it can also use those wires at the same time for generating extra heat.

So this is where I see one of the possible downsides to this Model 3 method. I'm not sure it can create any extra heat beyond the waste from operation while the car is driving. But certainly it can do it while parked, and there definitely should be a software control made available that could let owners turn it on.
Click to expand...
If the internets is to be believed the dedicated pack heater in the S/X only outputs 6 kW of heat, whereas the Model 3 motors can supposedly produce ~5 kW of heat. Realistically it takes a lot of heat to warm up ~1000 pounds of battery quickly. It is why Bjorn said it was better/faster to hammer the throttle than it was to wait on the battery heater to get higher supercharging rates.
 
#26
diamond.g said:
If the internets is to be believed the dedicated pack heater in the S/X only outputs 6KW of heat, whereas the Model 3 motors can supposedly produce ~5KW of heat. Realistically it takes a lot of heat to warm up ~1000 pounds of battery quickly. It is why Bjorn said it was better/faster to hammer the throttle than it was to wait on the battery heater to get higher supercharging rates.
Click to expand...

From some reading around the Model S and X forums, it seems that the pack heater pulls about 5 kW in operation. The Model 3 is supposedly capable of 4 kW but I've only seen 2.5 kW at 10F. Perhaps it ramps up to higher power in colder temperatures.

It's crazy to think that my little 24 kWh Fiat 500e has a 6 kW battery heater. I don't know how much it actually consumes or what its duty cycle is... it's very difficult to get solid information about its operation.
 
#27
diamond.g said:
If the internets is to be believed the dedicated pack heater in the S/X only outputs 6 kW of heat, whereas the Model 3 motors can supposedly produce ~5 kW of heat.
Click to expand...
I had not seen any references that high. Care to supply us an internets for that?
Big Earl said:
From some reading around the Model S and X forums, it seems that the pack heater pulls about 5 kW in operation. The Model 3 is supposedly capable of 4 kW but I've only seen 2.5 kW at 10F. Perhaps it ramps up to higher power in colder temperatures.
Click to expand...
I had also been wondering about the effectiveness of how far it has to transport the heat. So given some amount of kW it is consuming to generate that heat in the motor, it then has to pass it along some kind of transfer medium to run to and through the battery pack, so I wonder how much heat is lost along the way moving it versus the S and X I think having that heater inside the battery pack, so with probably less transport loss.
 
#28
I have written Tesla about this issue a few times. Please everyone do the same. We need more power to heat the battery. I've seen very low SuperCharging rates even after driving on the highway all day. Sure you can stomp the accelerator lots before reaching the charger to help bring the temperature up but its not practical to do all the time. There is a thread about this in the Model 3 Owners club forum.
From what I have observed taking temperature readings of the superbottle the car only wants to warm the fluid up to around 15C. That is clearly not warm enough to take 120 kW charging. So like others have mentioned, your charge rate never seems to increase. My S would always slowly warm up and take more charge power.
 
#29
Rocky_H said:
I had not seen any references that high. Care to supply us an internets for that?

I had also been wondering about the effectiveness of how far it has to transport the heat. So given some amount of kW it is consuming to generate that heat in the motor, it then has to pass it along some kind of transfer medium to run to and through the battery pack, so I wonder how much heat is lost along the way moving it versus the S and X I think having that heater inside the battery pack, so with probably less transport loss.
Click to expand...
@Big Earl was right. The numbers came from TMC. Does the API accurately report the battery heating for the 3 when that message appears?
 
#31
Besides very cold temps my 3 charging is very restricted even when it is 50 outside and I have hammered the pack and regen. It's all over the place depending on SOC but it is MUCH more restricted than my 85D. In fact I don't think the 3 pack can take full power at all SOC levels unless it is at least 80 degrees. I have tested this repeatedly and get varying results. Also if it is restricted at say 50 degrees and at a low SOC a rate of 50kw does not warm it to ramp it up faster over time, it even goes down at time when it should be going up. Very odd behavior.
 
#32
Another data point. Low 30’s here in Michigan. I had driven maybe 15 miles doing a few errands and stopped at the grocery store whcih happens to have a SC. They were pretty empty so I hooked up and only got 20kw from 65-80%. I still had Regen dots even after the SC. The car had sat in my unheated garage for 4 days with outside temps in the 20’s. I did preheat and charge a bit before the errands but still only had maybe half or a little less of Regen available Chalked it up to cold weather.

Still happy
 
#33
If you are paying by time at the lower tier and only getting 17KWH, the charging cost will be significant! In NM the lower tier cost is currently around 13 cent/minute (??) at 17KW that is around 46 cents/KW. That would be around $7.80 to get best case about 68 miles.
 
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#34
Mikeat00 said:
Another data point. Low 30’s here in Michigan. I had driven maybe 15 miles doing a few errands and stopped at the grocery store whcih happens to have a SC. They were pretty empty so I hooked up and only got 20kw from 65-80%. I still had Regen dots even after the SC. The car had sat in my unheated garage for 4 days with outside temps in the 20’s. I did preheat and charge a bit before the errands but still only had maybe half or a little less of Regen available Chalked it up to cold weather.

Still happy
Click to expand...

100% normal
 
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