Too cold for heat pump efficiency numbers

[teslarati97]

Did some cold weather testing for the F56 and U25 at -14F and lower. I cold soaked both vehicles outdoors overnight and ran climatization (10 minutes). Overall, my efficiency numbers are about 2mi/kWh for the F56 and 1.1mi/kWh for the U25. I’m happy to report the U25 was extremely toasty warm and the E-Power was at least 70% (no bar segments), while the F56 had 3 bars of E-Power.

Am I concerned about the very cold weather GoM 70 mile max range at 100% SoC in the U25? Absolutely not! If I really needed the range, I would set the charge limit to 100%, leave the EVSE plugged, and schedule a departure time (at least 3 hours in advance). I still prefer driving the F56 over the U25, but happy to have both!

 

[ENirogus]

regular old school heat pumps don't do much under 20 something degrees.
I am surprised that all EVs don't have vapor injection pumps since you can buy a whole minisplit with that tech for 800 bucks

 

[teslarati97]

regular old school heat pumps don't do much under 20 something degrees.
I am surprised that all EVs don't have vapor injection pumps since you can buy a whole minisplit with that tech for 800 bucks

Well Ford already patented it so I don't think they want to share.

 

[ENirogus]

Well Ford already patented it so I don't think they want to share.

Well, vapor injection has been around for more than 20 years, so I am sure that Ford's patent has its limitations

 

[teslarati97]

Yes it would be probably limited to R-1234yf or R-290. I highly doubt it is for R-744.

It's a shame that R-22 and R-410A have been phased out, back to the drawing board...

 

[ENirogus]

Yes it would be probably limited to R-1234yf or R-290. I highly doubt it is for R-744.

It's a shame that R-22 and R-410A have been phased out, back to the drawing board...

Well, patents are pretty limited. Unless you are the first one to invent 'tabletop fusion' you can only patent 'a method of creating' tabletop fusion. Since vapor injection is well off patent, the simple act of putting it in a moving vehicle is not a solid patent. The details can be patented, unless someone has done it before. Novel and non obvious as they say.
And no it is no a shame they phased out R-22. 410, well, maybe.

 

[teslarati97]

Temperatures are back in the 40F region, and the U25 efficiency has jumped up to 2.75mi/kWh (1.1mi/kWh when -14F and colder). The F56 is around 3mi+/kWh and both are with winter tires.

 

[revorg]

I've been averaging 2.79mi/kwh, but the daily temps have been up and down (very warm and very cold).

 

[teslarati97]

I've been averaging 2.79mi/kwh, but the daily temps have been up and down (very warm and very cold).

Goes to show how much HVAC can eat away at the efficiency, with resistive heating being the most inefficient.

 

[revorg]

You're assuming I use the heat. I don't turn the heat on until the temps are 10F or below.

 

[SameGuy]

I leave mine set to "Auto" and 19°C (66°F) pretty much year-round. If I don't have fogging issues on colder days, I turn off AC – especially if I'm pushing the range a bit – but otherwise I'd say AC is on 90% of the time, winter or summer. There are short periods in spring or fall that I shut it all off and roll down the windows and/or open the roof.

 

[ENirogus]

You're assuming I use the heat. I don't turn the heat on until the temps are 10F or below.

I dunno, I'll take your word for it but once you get into the 20's most cars start to fog up.

 

[CuriousGeorge]

Well since we're sharing.

With summer tires I don't drive my SE when it is below 40 deg F. Between that and an insulated (albeit unheated) garage, I rarely need to use the heat pump, much less the seat heaters. Unless it's really warm, I also prefer to drive with the roof open versus using the A/C. This undoubtedly contributes to the fact that I average 5 mi/kWh.