heater current draw comparison/ normal heater vs heat pump

[kmp647]

OK so I have a 2012 and actually used the heater today!
outside temp 30F
car garaged and preheated
set auto temp to 68F
ECO mode
the car used 1.5kw to 1.7 kw(by the energey screen meter) all the way to work and cost me about 1 bar plus

Can somone with a 2013 SV or SL (heatpump model)
please try a similar test cold morning ~30F
ECO mode or equivilant
set thermosta auto to 68F

please report the heater consumption in KW via the energy screen

thank you

 

[XeonPony]

I had all ready don so but I'll do it here: 1.5Kw average with spikes to 3Kw (Defrost cycle I suspect) temp -13c

 

[kmp647]

1.5kw ???/ so where is the efficiency advantage?

on your car is there eco setting that reduces climate contrl consumption ?
do you have that on?

how can it be? first we have this wonderful heat pump system
then owners in warm areas report it uses more energy to cool than the 2011/2012 system

now your report indicates the same heater consumption as my toaster coil model?

what ?

 

[Klayfish]

My rough results...I didn't watch the screen religiously, but my parameters were similar to yours. 30 degrees on my drive in, actually dropped into the upper 20's at points, according to my car. I set my thermostat at 68 also. 2013 SL. When I first turned it on, it spiked to about 3.5. Stayed at 3 for a minute or two. Then around 1.5 for a while. After a while, it finally dropped below 1, but would occassionally go to 1.5.

 

[Nubo]

If you've pre-heated the cabin is at 77F. If you set to 68F as you leave, the air conditioning will come on and you'll spend more energy to get rid of the heat you already created. Leave the climate control off for the first portion of your journey until you feel the cabin is below your preferred set point before turning the heat back on.

As far as the heat pump; there was a chart prior to the 2013 release that showed range effect. As I recall the crossover point was somewhere in the mid 20's F. Above that and the heat pump begins to show an advantage. The advantage is more pronounced above freezing. At 30F you probably have some advantage but not dramatic. That's the nature of heat pumps. They are transferring heat from the outside air. Below a certain temperature it just takes too much work to extract heat from the outside air, and the resistive heater has to be used instead. The heat pump is at its best in chilly, not frigid temperatures.

 

[Berlino]

1.5kw ???/ so where is the efficiency advantage?

He states, -13c. This is 8.6°F.

 

[essaunders]

I thought eco mode limited heater to ~1.5kw. I know this morning I was pulling waay more on my drive in, but I was in "D"

you really need to measure how much heat you are getting out for the given energy in. I suspect your 2012 was just 'colder' than a 2013 under the same conditions.

For this comparison we really need a 2012 and 2013 with heat pump to cold soak together overnight and then drive the same commute. We'd need a common drive mode and heat temp target as well as a record of cabin temp over the commute. (or just skip the commute and have the cars on)

 

[Stanton]

I'm not sure conducting this test in "ECO" mode is a very good indicator of the differences since it caps/curbs the current draw on the heater; doing it in "D" would be much more useful.

 

[bradbissell]

This morning it was 25F. My 2013SV had been parked outside and charged to 100% just prior to leaving at 5am. The battery was 39F and I had a pre-heat timer set for my departure (temp set to 72).

Setting the heater to 68 in eco mode, the heater capped at 1.5kw as expected and bounced between 1.25 and 1.5kw for my entire commute.

The heat produced in eco mode was more than enough to keep the cabin warm for the entire trip.

 

[TomT]

No surprise there. At that temperature (8.6F) you are primarily using the resistance heater rather than the reverse cycle heater.

I had all ready don so but I'll do it here: 1.5Kw average with spikes to 3Kw (Defrost cycle I suspect) temp -13c

 

[epirali]

OK so I have a 2012 and actually used the heater today!
outside temp 30F
car garaged and preheated
set auto temp to 68F
ECO mode
the car used 1.5kw to 1.7 kw(by the energey screen meter) all the way to work and cost me about 1 bar plus

Can somone with a 2013 SV or SL (heatpump model)
please try a similar test cold morning ~30F
ECO mode or equivilant
set thermosta auto to 68F

please report the heater consumption in KW via the energy screen

thank you

33 degrees out, black car, preheated to 70 via charger power. Driving with temp inside set to 70 I am drawing from 0 to maybe 0.7, averaging around. .2-.3.

 

[XeonPony]

ya most heat pumps surrender at -20c in a house seting, let alone the tiny HX in a car, I still want to know what they are doing with the waste heat in the inverter/motor! as I am certain their should be some usable amount there!

 

[Ingineer]

I've done extensive testing of many of the LEAF's systems, including the heating system. I can say with confidence that the heat pump draws (on average) about 3 times less overall energy for the same heating. (That may not apply to really cold areas though)

Also; the energy screen gauge is not that accurate. It averages heavily, and doesn't handle the peaks well. The resistance heater is PWM'd at a very low frequency, yet this is not reflected in the on-screen gauge. It is instantly obvious with an external ammeter though.

-Phil

 

[planet4ever]

I still want to know what they are doing with the waste heat in the inverter/motor! as I am certain their should be some usable amount there!

I don't have a 2013 service manual, but in 2011 they were mostly venting it. There were two coolant loops, separate except for a common reservoir. One loop handled the heater. The other handled the charger, inverter, DC/DC converter, and motor. The cooling loop used a conventional automobile radiator at the front of the car, with a fan. There could be some heat transfer via the reservoir, but I wouldn't expect it to amount to much.

I don't have numbers, but my guess is that there is a significant temperature difference between the loops. The idea is to keep the electronics as cool as possible, so the coolant in that loop might be (again guessing) not much more than lukewarm. If so, that's not going to be much help in warming up freezing air.

Ray

 

[XeonPony]

going have to put some thermal coupls on the lins and do some measuring, as there are some heat scavenging systems that could be employed to boost heat pump yeild and give the electronics a good temp range to run at. I've yet to dig into mine too much.

 

[Ingineer]

There isn't appreciable waste heat, but yes, with a heat pump it would be possible to recover it. However, it's clear Nissan's goal was to reduce the cost as much as possible in the LEAF, so that it could achieve a bigger market. Adding extra components (which also add weight) for a little more heater efficiency doesn't fit into this thinking.

-Phil