Heat Pump Range Loss?

[TZLAFAN85]

Now that some parts of the country have had some cold days, how much range loss is being experienced on the new MS with a heat pump? On my 2015 I lose ~40-45% of my range in the winter if I don't precondition so I'd like to understand what that looks like on the new cars before I take delivery in a few weeks.

 

[sandman1330]

I'm curious about this too, but even more so, I'm curious how effective the heat pump is. For those of us in the Great White North, I'm concerned as to how effective it will be in -40*C... I know they also use some of the battery heat to augment it, but I'd still like to hear some experiences.

 

[SSonnentag]

I read somewhere that the heat pump-equipped cars still have resistive heating as well, so at those extreme temperatures I have serious doubts that the heat pump will be any more efficient than the older cars. At more moderate temperatures, say 0*C and above, the battery hit should be similar to the AC usage during the summer.

 

[razh]

The heat pump will save you about 3 kWh, which translates into reducing your Supercharging time by about 1.5 minutes. Overall he estates about 5% range improvement.

 

[PCMc]

say 0*C and above, the battery hit should be similar to the AC usage during the summer.

That statement would seem to apply once the battery is warmed up, but you'll still have the need for high draw to warm up the mass of the battery when it has had a chance to cold soak combined with taking short trips. Yes, the heat pump still has potential benefit of doing that more efficiently, but still have the same thermal mass of the battery that must be warmed, which requires a set amount of energy. Similar to to energy draw of the AC when the car has sat in the sun, interior is heat soaked, and the AC is running max to initially cool the cabin versus the draw after the cabin has cooled off and AC is just needing to maintain temp.

If your operating profile is shorter trips, then you'll still likely to see show big range losses even with a heat pump. If you're talking about a day long drive cross country in cold ambient conditions, then this would be the case where the heat pump has the most potential for improving range.

 

[SSonnentag]

That statement would seem to apply once the battery is warmed up, but you'll still have the need for high draw to warm up the mass of the battery when it has had a chance to cold soak combined with taking short trips. Yes, the heat pump still has potential benefit of doing that more efficiently, but still have the same thermal mass of the battery that must be warmed, which requires a set amount of energy. Similar to to energy draw of the AC when the car has sat in the sun, interior is heat soaked, and the AC is running max to initially cool the cabin versus the draw after the cabin has cooled off and AC is just needing to maintain temp.

If your operating profile is shorter trips, then you'll still likely to see show big range losses even with a heat pump. If you're talking about a day long drive cross country in cold ambient conditions, then this would be the case where the heat pump has the most potential for improving range.

True. In my S it seems to take about 1.5-2 hours of winter driving before everything has heated up to an efficient state. Even with only resistive heating, the cold winter efficiency approaches that of summer efficiency after those initial couple of hours.