User avatar
planet4ever
Posts: 4674
Joined: Sat Apr 03, 2010 9:53 pm
Delivery Date: 02 May 2011
Leaf Number: 1537
Location: Morgan Hill, CA, south of San Jose

Re: has anyone actually measured the efficiency of the heat

Thu Nov 28, 2013 3:49 pm

Rauv wrote:I am making the assumption that after a full charge (8 hours+balancing) followed by a pre-heat, means that all of the load from the wall effectively goes to heating the cabin. Maybe that is not the case and the traction battery provides some energy to heat the cabin even while plugged in?
I don't know whether the heat pump runs from 12v DC or 400v DC, but surely it doesn't run from AC, either 120v or 240v. Therefore the on-board charger has to be running during your preheat. That means the cooling system is also running, and the DC/DC converter is likely to be running to supply the 12v for the cooling system, if not also the heat pump. Both the charger and the DC/DC converter are water cooled, and the heat the coolant extracts goes to the outside of the car, not the cabin.

So you still have a number of variables for your test.

Ray
End of April 2013: Traded my 2011 SL for a 2013 S with charge pkg.

User avatar
TomT
Posts: 10647
Joined: Sun Aug 08, 2010 12:09 pm
Delivery Date: 01 Mar 2011
Leaf Number: 000360
Location: California, now Georgia
Contact: Website

Re: has anyone actually measured the efficiency of the heat

Thu Nov 28, 2013 3:52 pm

It's powered from the pack.
planet4ever wrote:I don't know whether the heat pump runs from 12v DC or 400v DC
Leaf SL 2011 to 2016, Volt Premier 2016 to 2019, and now:
2019 Model 3; LR, RWD, FSD, 19" Sport Wheels, silver/black; built 3/17/19, delivered 3/29/19.

iluvmacs
Posts: 145
Joined: Fri Oct 28, 2011 8:08 pm
Delivery Date: 20 Dec 2011
Leaf Number: 411121
Location: Madison, WI

Re: has anyone actually measured the efficiency of the heat

Sat Dec 21, 2013 2:58 pm

As someone who has had both a '12 and a '13 Leaf in Wisconsin winters, I can testify that the '13 heat pump is noticeably more efficient. I don't have real numbers, just anecdotal evidence from the Energy Monitor screen that I always have up while driving. We only run the heat when it's well below freezing. My '12 Leaf would be a solid 5kW to start, and then steady 3-4kW after that. The '13 is usually 4kW to get started, and then 1.5-2kW after that to maintain. Big difference. It also heats up WAY faster and hotter than the old one. This was actually one of the primary reasons we traded in for the '13.
Delivered 6/22/13: 2013 SV+LED/QC+Prem, Blue Ocean
Loved 12/20/11-6/22/13: 2012 SL #15733 (orphan), Blue Ocean, lifetime 4.8 mi/kWh (11,356 mi). First Leaf in Wisconsin!
2018 Tesla Model 3 LR, red

Wisconsin Leaf/EV owner? Join our group!

LKK
Posts: 290
Joined: Sat Jan 15, 2011 10:27 am

Re: has anyone actually measured the efficiency of the heat

Sat Dec 21, 2013 5:55 pm

I have no idea how efficient is the Leaf's heat pump, however the DoE did a test on the Mitisubihi split heat pump and rated it with a coefficient of performance in the heat cycle of 4.2. That means for every watt going in, the unit produces the equivalent of 4.2 watts of heat. I believe COP is measured at 50 degrees and drops off significantly as the temperature drops.

http://www.nrel.gov/docs/fy11osti/52175.pdf" onclick="window.open(this.href);return false;

Since COP drops off as the outside temperature drops my understanding is the heat pump is pretty useless as the temperature drops near zero. As such, they require resistive heat to supplement, and this draws heavily on the battery. It would be nice it there was instead, a propane powered catalytic heater to supplement the heat pump. I don't think heating directly from a catalytic heater is a good idea as they deplete oxygen from the air, but using it to pre-heat the air going to the heat pump would eliminate this danger. Propane could come from the standard 1lb propane tanks that are widly used with camping equipment.

User avatar
surfingslovak
Vendor
Posts: 3809
Joined: Mon Jun 13, 2011 1:35 pm

Re: has anyone actually measured the efficiency of the heat

Sat Dec 21, 2013 6:25 pm

LKK wrote: Since COP drops off as the outside temperature drops my understanding is the heat pump is pretty useless as the temperature drops near zero. As such, they require resistive heat to supplement, and this draws heavily on the battery.
This not quite correct, and has been debunked on this forum several times. While the efficiency of the heat pump drops with lower ambient, it offers a significant benefit over a resistive heater all the way down to 0F. You can see that on the graph below, which Nissan used during the launch presentation of the 2013 LEAF. The heat pump and the resistive heater were set to 77F, and the range was then measured at different ambient temperatures.

Image
LKK wrote: It would be nice it there was instead, a propane powered catalytic heater to supplement the heat pump. I don't think heating directly from a catalytic heater is a good idea as they deplete oxygen from the air, but using it to pre-heat the air going to the heat pump would eliminate this danger. Propane could come from the standard 1lb propane tanks that are widly used with camping equipment.
Volvo did this, but they used ethanol instead of propane. Arguably, in some parts of the world reliable source of heat can be a matter of survival.

johnrhansen
Posts: 1100
Joined: Mon Aug 12, 2013 7:23 pm
Delivery Date: 15 Jun 2013
Leaf Number: 409445
Location: Seattle, WA

Re: has anyone actually measured the efficiency of the heat

Sat Dec 21, 2013 7:20 pm

now that winter is here I'm really noticing how poorly the resistance heater is working in my 2013 s. It really gobbles up power. I've checked more thoroughly the difference berween heat on and off, especially in the slow city driving I do so much. I really wish I had bought the SV with a heat pump. I use about twice as much energy when the weather gets really cold. I should have researched more when I bought it. I don't want to lose my shirt trading it in, so it looks like I'm stuck with it. I take back everything I said before. When it gets really cold and rainy, I just drive my ice truck now. It needs a workout now and then anyway. The leaf is really a fair weather car. Might as well be a convertible.
2013 S model with quick charge package.
AV 30 amp level 2 EVSE, Bosch PowerMax 30 Amp EVSE, EVSE upgraded EVSE.

DaveinOlyWA
Posts: 14692
Joined: Sat Apr 24, 2010 7:43 pm
Delivery Date: 16 Nov 2019
Leaf Number: 319862
Location: Olympia, WA
Contact: Website

Re: has anyone actually measured the efficiency of the heat

Sat Dec 21, 2013 9:05 pm

johnrhansen wrote:now that winter is here I'm really noticing how poorly the resistance heater is working in my 2013 s. It really gobbles up power. I've checked more thoroughly the difference berween heat on and off, especially in the slow city driving I do so much. I really wish I had bought the SV with a heat pump. I use about twice as much energy when the weather gets really cold. I should have researched more when I bought it. I don't want to lose my shirt trading it in, so it looks like I'm stuck with it. I take back everything I said before. When it gets really cold and rainy, I just drive my ice truck now. It needs a workout now and then anyway. The leaf is really a fair weather car. Might as well be a convertible.
i just got my S yesterday and the difference due to the special on the S would have been $100 a month. After driving my 2011 with no heated seats or steering wheel, the 2013 has been a dream but then again, it has not been below 42º and I am well prepared for cold. First thing I did was turn seat heaters from high to low. High was just a bit too warm for me. Cant wait to see how it works when temps hit the 20's...
2011 SL; 44,598 mi, 87% SOH. 2013 S; 44,840 mi, 91% SOH. 2016 S30; 29,413 mi, 99% SOH. 2018 S; 25,185 mi, SOH 92.23%. 2019 S Plus; 7059.6 mi, 95.35% SOH
My Blog; http://daveinolywa.blogspot.com" onclick="window.open(this.href);return false;

johnrhansen
Posts: 1100
Joined: Mon Aug 12, 2013 7:23 pm
Delivery Date: 15 Jun 2013
Leaf Number: 409445
Location: Seattle, WA

Re: has anyone actually measured the efficiency of the heat

Sat Dec 21, 2013 11:57 pm

It's always heated very well and defogged just fine regardless of how cold or damp it was, and if you don't have far to go, it works just fine. I see you are in olympia and I drive down there periodically. When it gets really cold, I can't make it there from Seattle unless I stop at the blink charger in fife. One time I was only getting 3 miles per kwh. When it's warmer and the heat is off I can make 4.8 easy., and arrive there with 20 percent to spare. Driving a leaf is a lot like being an old time bush pilot. You need to be really cognizant of the weather and of your machine or you won't make it. From now on I dont leave king county in it unless the weather is decent. Just too much to think about.
DaveinOlyWA wrote:
johnrhansen wrote:now that winter is here I'm really noticing how poorly the resistance heater is working in my 2013 s. It really gobbles up power. I've checked more thoroughly the difference berween heat on and off, especially in the slow city driving I do so much. I really wish I had bought the SV with a heat pump. I use about twice as much energy when the weather gets really cold. I should have researched more when I bought it. I don't want to lose my shirt trading it in, so it looks like I'm stuck with it. I take back everything I said before. When it gets really cold and rainy, I just drive my ice truck now. It needs a workout now and then anyway. The leaf is really a fair weather car. Might as well be a convertible.
i just got my S yesterday and the difference due to the special on the S would have been $100 a month. After driving my 2011 with no heated seats or steering wheel, the 2013 has been a dream but then again, it has not been below 42º and I am well prepared for cold. First thing I did was turn seat heaters from high to low. High was just a bit too warm for me. Cant wait to see how it works when temps hit the 20's...
2013 S model with quick charge package.
AV 30 amp level 2 EVSE, Bosch PowerMax 30 Amp EVSE, EVSE upgraded EVSE.

sendler2112
Posts: 261
Joined: Wed Jan 06, 2016 5:05 pm
Delivery Date: 07 Jan 2016
Location: Syracuse, NY USA

Re: has anyone actually measured the efficiency of the heat

Thu Nov 17, 2016 5:54 pm

Rauv wrote:I have measured (and will post a graph hopefully this weekend) of the load from the wall after a full 100% charge, followed immediately by a pre-heat session. I have done this several times and the load from the wall during the pre-heat is around 1500 watts, to get heat rise from 30 deg. F ambient to 65F in the 'cabin'.

I am making the assumption that after a full charge (8 hours+balancing) followed by a pre-heat, means that all of the load from the wall effectively goes to heating the cabin.
This is with a heat pump car? Still no one has done this test with a space heater car? Maybe 4 Kw on high instead? A 40 mile highway commute will use up 10kWh and take 45 minutes. The space heater worst case would be 3kWh vs 1kWh for the heat pump. The total would be 13kWh vs11 if the space heater really stayed that high the whole time. So maybe about 15% highway range advantage to the heat pump car on a 0C day.

sendler2112
Posts: 261
Joined: Wed Jan 06, 2016 5:05 pm
Delivery Date: 07 Jan 2016
Location: Syracuse, NY USA

Re: has anyone actually measured the efficiency of the heat pump

Thu Nov 17, 2016 7:07 pm

Here is a chart of aux power loads of various leaf drivers at various temps.
.
.
Image
.
.

Return to “General / Main Owners Forum”