clonmac
Posts: 2
Joined: Wed Oct 15, 2014 11:40 am
Delivery Date: 20 Apr 2014

Climate control energy usage?

Wed Feb 14, 2018 6:44 am

I'm an original owner of a 2014 Nissan Leaf S. After about 4 years of ownership, I feel I've come intimately intune with how the range of my car and achieving maximum range when needed. I've never once become stranded. It has been a fantastic car for me.

However, because I only own the base model, I do not have the onscreen dashboard readouts for how much energy (kW) the climate control is using. So I was hoping some people here would be able to lay out some general guides as to how much kW drain is put on the battery under varying use cases with the climate control system (@ varying outside temps and temperature settings).

A few questions I have:

1) Does the fan speed have any measurable extra drain?
2) A sub-freezing temperatures, how much extra drain is there?
3) What's the difference between a temperature setting of say 60 versus 70?
4) If reset, does the miles per kWh estimate on the dashboard account for the current drain of the climate control system?

According to the Nissan Leaf range chart I've long had, it says to subtract 1 fuel bar for every hour of usage @ 1.5kW of heat/cool climate control. The problem is that I don't know whether or not my climate control usage is running at 1.5kW. If it is a lot more than that, then I could be underestimating my climate control drain by a lot.

Often, what happens during my actual real life scenarios is during drives where I feel I might be really close to making it to my destination with a charge left, I end up running without heat for a little while only to find out that when I reach my destination I could've run with heat the entire time and still been safe. I'm often overly conservative in my estimate just to make sure I reach my destination. I feel if I had a better understanding of how much drain the climate control system is putting on my battery, then I'd be much more comfortable using it because I can already estimate very well how far I'll be able to go based on my miles per kWh efficiency.

jjeff
Posts: 1690
Joined: Wed Jan 13, 2016 9:10 am
Delivery Date: 13 Jul 2014
Leaf Number: 422121
Location: MSP MN

Re: Climate control energy usage?

Wed Feb 14, 2018 4:08 pm

As I have both a '12SL(with resistive heat, albeit with a liquid loop vs air heating post '12) and a '13S with resistive heat with air, I'm probably in a pretty good condition to answer your question. Post '12 Leafs with the energy screen(SV/SL) have the heat pump heater, which in general will draw quite a bit less than our resistive heaters.

That said, this is what I've observed:
1. Indirectly, that is a faster fan speed will draw heat away from the heat source quicker, requiring it to turn on more and thus draw the current for a longer time.
2. Again it's not so much that the heater draws more current when it gets colder but rather how long draws the current. Very cold temps the heater may draw full current 50% of the time, warmer temps will cycle the heater more.
3. If the heater is running setting the thermostat to 60 or 70(if the cabin temp is cold) isn't so much the issue but rather the fan speed. Personally I set my heater to 80 and fan speed to 1, 2 or max of 3. The car will never reach 80(it's just a psychological thing) but the heater will cycle with the rather slow fan speed. Another reason to limit the fan speed (without using recirc) is with a high fan speed you'll be pulling in more cold outside air, that has to be heated. With a slow fan speed you limit cold outside air and get a higher discharge temp, which again will cycle your heater more. Now if your lucky enough to live in an area of the country that is very dry and are able to use recirc or even partial recirc without your windows fogging, that will be the most efficient way to heat your car. Unfortunatly whenever I've used recirc or even partical recirc my windows tend to fog up and require me to turn off the recirc :(
4. Good question, I don't know that one but would think so?? maybe someone else knows.

When the heater is on, on my '12 it tends to draw ~5-6 kw but again doesn't run all the time, I guess if you figured it only ran 50% of the time I suppose you could say it's average draw was 2.5-3kw, 25% of the time could average ~1.25-1.5kw. Now a heat pump will be totally different in more moderate temps, it's maximum draw can be quite a bit less than 5-6kw, increasing in draw as the temps get colder up to <10F where it probably draws as much as our resistive only Leafs because heat pumps don't really work well in such bitter temps and the heatpump Leafs have a resistive heater for backup in such cases.
2012 SL purchased used 2/'16
2013 S w/QC purchased new
Juicebox Premium 60a L1/L2 EVSE, Ebusbar 16a L1/L2 EVSE
'12 EVSEupgrade'd 20a L1/L2 EVSE, '13 EVSEupgrade'd adjustable 6-20a L2, 6-13a L1 EVSE
Zencar 13, 20, 30a L1/L2 portable EVSE
GE Durastation 30a

GerryAZ
Gold Member
Posts: 1758
Joined: Mon Nov 22, 2010 6:47 pm
Delivery Date: 12 Jun 2011
Location: Phoenix, AZ

Re: Climate control energy usage?

Wed Feb 14, 2018 10:04 pm

Dashboard miles/kWh does account for climate control use, although the number is higher than actual efficiency using miles driven and power consumption measured from the wall. Leaf Spy (at least professional version) show climate control energy use so you may want to purchase the app and a suitable OBDII adapter.
Gerry
Silver LEAF 2011 SL rear ended (totaled) by in-attentive driver 1/4/2015 at 50,422 miles
Silver LEAF 2015 SL purchased 2/7/2015

clonmac
Posts: 2
Joined: Wed Oct 15, 2014 11:40 am
Delivery Date: 20 Apr 2014

Re: Climate control energy usage?

Thu Feb 15, 2018 5:58 am

Thanks for the answers guys. I hadn't thought about the fan speed drawing heat away from the heater quicker, which would result in more frequent cycle times. That makes total sense.

It is good to know the mi/kW readout does account for climate control use. It always seemed like it did, but I didn't know for sure.

Generally what I do to estimate my usage is to always reset my trip meter and my energy efficiency meter and every full charge. I then know exactly how many miles I've driven and the efficiency I've had during that full battery charge cycle. To be conservative, I estimate I have about 20kWh of usage energy (even though it is more like 21kWh). That also makes the math easier. I then simply multiply the miles/kWh efficiency number on the dash by 2 and move the decimal over one place to multiply it by ten. I then know my max mileage based on my current efficiency and then subtract the miles shown on my trip meter to know how much further I can drive. That's been working well for me so far.

So if my efficiency is 4.2, then I slide the decimal over to get 42 and then multiply it by 2 to get 84 miles of range. Since I'm basing this calculation on only 20kWh of usage energy, I know I have 1 extra kWh to spare and that my estimates will be conservative. Interestingly enough is that after I've driven about 10-15 miles after a full charge, I've found that the on dash range estimation is fairly accurate to this calculation so long as my driving habit and climate control usage is fairly consistent.

It is good to know that climate control is somewhat accounted for in that calculation now. I also didn't know that LeafSpy was usable while the car was on and in motion (is that true?). I will need to look into getting that now. I thought it could only be used for diagnostics while stationary. I

Also, the 2014 Model S only has a resistive heater? All this time I thought it had a heat pump. Bummer!

GerryAZ
Gold Member
Posts: 1758
Joined: Mon Nov 22, 2010 6:47 pm
Delivery Date: 12 Jun 2011
Location: Phoenix, AZ

Re: Climate control energy usage?

Thu Feb 15, 2018 7:06 pm

I keep Leaf Spy Pro running all the time the car is on. I like the tire pressure display (with alarm that can be set for any pressure). I leave the Bluetooth unit plugged in to the OBDII port unless I am parking the car for more than a couple of days because it could interfere with the automatic charging of the 12-volt battery when the car is off and I want to avoid a dead battery. I turn the phone or tablet off whenever I turn the car off.
Gerry
Silver LEAF 2011 SL rear ended (totaled) by in-attentive driver 1/4/2015 at 50,422 miles
Silver LEAF 2015 SL purchased 2/7/2015

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