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seat warmer power consumption

Posted: Sun Jan 24, 2016 1:46 pm
by ytrottier
What is the power draw of the seat warmers on the 2016 Nissan Leaf? A previous post ( viewtopic.php?t=10617 ) guessed 60W or below based on other cars, but I have the impression mine is using a lot more. Based on casual observation during my daily 200km commute, the high setting seems to consume an extra bar per hour, which would put the power draw over a kilowatt!

I've started keeping more careful data, and I admit it's hard to distinguish against the effects of wind, temperature, and charge history. But does anyone have more reliable information on this? What's the efficiency of the 360V-12V DC-DC conversion?

Re: seat warmer power consumption

Posted: Sun Jan 24, 2016 1:53 pm
by LeftieBiker
Are you running one seat warmer, or both/all of them on High? I'm not sure if your car has rear seat warmers, but I suggest you check.

Re: seat warmer power consumption

Posted: Sun Jan 24, 2016 3:45 pm
by dhanson865
get an OBDII adapter, a phone or tablet, and leafspy app and you'll know your power draw for

Motor (drive motor)
Aux (lights, radio, etc)
Heater (just the heat pump or PTC heater for the forced air from the vents)
A/C (just the heat pump or AC unit for forced air from the vents)

You'll find with just the car running Aux will be 1 or 2. Add the seat heater on low, windshield wipers, headlights it might hit 3.

I've never used the seat heater on high but if you have this you'll see power draw change in digital numbers divided by enough categories to make it possible to isolate one or two items and then you can tell us how much your car is using.

Be sure to test in a warm garage and out in the cold. Test with climate control turned off, lights off, radio off, etcetera to be sure you don't have anything else cutting on when you check.

Maybe some of the power draw you think is coming from the seat heater is really the PTC heater (climate control) or the Pack heater (only if batttery pack hits -4F) kicking on at the same time you are using the seat heater?

Re: seat warmer power consumption

Posted: Sun Jan 24, 2016 4:10 pm
by ytrottier
I'm only running one seat warmer for the driver, the others for front and rear passengers are off. The climate control is always off. The coldest I've driven in was 7F, so the pack heater shouldn't be on yet.

I want an OBDII adapter, but can't splurge on toys right now. The numbers you give, what units are they in? Amps at 360V?

I've started writing down data from the percent battery charge on the dash, but I'll need two days with similar wind and temperature conditions for a good comparison.

Re: seat warmer power consumption

Posted: Sun Jan 24, 2016 4:29 pm
by EVDRIVER
The seats are 12V not HV! Only the AC and heater are HV.

Re: seat warmer power consumption

Posted: Sun Jan 24, 2016 8:31 pm
by dhanson865
ytrottier wrote:I want an OBDII adapter, but can't splurge on toys right now. The numbers you give, what units are they in?


They vary

motor is 0 to 100 KW scale, 1 unit = 100W.

aux is 1 unit = 100W.

Heater is 1 unit = 250W. It goes off the top of the scale easier because the PTC heater uses so much power.

AC is 1 unit = 50W (edited)


I'm rereading the 140+ pages of the leafspy thread to confirm.

edit: official word is 100w, 100w, 250w, 50w from viewtopic.php?f=44&t=14285&start=1080#p412890

Re: seat warmer power consumption

Posted: Sun Jan 24, 2016 8:34 pm
by ytrottier
I understand the Leaf seat warmers are 12V, but I'm not sure why EVDRIVER points that out. I guess that does mean the seat power can't be much higher than 60W, otherwise some big cables would be showing. I'm still suspicious of the DC-DC efficiency though, since the 12V battery is charged from the 360V battery.

Thank you dhanson865!

Re: seat warmer power consumption

Posted: Sun Jan 24, 2016 9:46 pm
by LeftieBiker
No one has seen significant range loss from the seat and wheel heaters. I too suspect you are seeing PTC-related drain.

Re: seat warmer power consumption

Posted: Mon Jan 25, 2016 9:30 pm
by keydiver
From the schematic from my 2012 manual, it appears that ALL of the seat heaters work off of the same 15 amp fuse, so the most any individual heater could draw is about 45 watts (at the point of blowing the fuse). My wife's home heating pad draws 25 watts on MAX, so I doubt the Leaf's seat heaters draw much more than that.

Re: seat warmer power consumption

Posted: Sun Jan 31, 2016 3:23 pm
by arnis
Measured :) . 1.1-1.3Amps on Low and 2-2.5Amps on High. That means 35W is really max they can do, times two or three.
Rear seat is similar (but maybe not identical as there are two bottoms, no backheaters.

Average consumption on trips is much lower because it is idling when it has reached the max.