Heated Seats & Steering Wheel - what's the power draw?

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garsh

Well-known member
Joined
Feb 12, 2011
Messages
1,173
Location
Pittsburgh PA
Has anybody measured the power draw of the heated seats or the steering wheel?

I think I'm noticing a decrease in efficiency when I use them, so I'm wondering if they aren't quite as insubstantial as I thought they were.
 
Not sure. I'm not even sure they impact the "accessories" reading, or whether its reading of them is accurate. I cannot imagine the draw is that substantial, though.

Segue: anybody else's steering wheel pulse? By this I mean it gets really nice and warm at first and then after a couple minutes will cool down until it's barely warm, then heat up again. Really annoying. This is my first car with a heated steering wheel though and it's a really nice comfort.
 
EatsShootsandLeafs said:
Not sure. I'm not even sure they impact the "accessories" reading, or whether its reading of them is accurate. I cannot imagine the draw is that substantial, though.
According to Phil ("Ingineer") the accessories meter is fake: it just adds up fixed values for the baseload and accessories that are on, for example, the headlights. So far as I am aware it doesn't have a value for the heated seats or steering wheel heater, perhaps because they weren't on the first LEAFs and the algorithm wasn't adjusted for cars with the cold weather package.
Segue: anybody else's steering wheel pulse? By this I mean it gets really nice and warm at first and then after a couple minutes will cool down until it's barely warm, then heat up again. Really annoying. This is my first car with a heated steering wheel though and it's a really nice comfort.
The steering wheel heater has a thermostat that cycles it on and off to keep it from overheating.
 
EatsShootsandLeafs said:
Not sure. I'm not even sure they impact the "accessories" reading, or whether its reading of them is accurate. I cannot imagine the draw is that substantial, though.

Segue: anybody else's steering wheel pulse? By this I mean it gets really nice and warm at first and then after a couple minutes will cool down until it's barely warm, then heat up again. Really annoying. This is my first car with a heated steering wheel though and it's a really nice comfort.

AFAIK, the 12V accessory draw is "estimated". Not sure how intelligently but it doesn't necessarily seem to track what I'm actually doing with the car. You can get some idea of the max current draw for the steering wheel and seat heating by looking at the fuses; will give you an upper bound and the actual use will be less. Definitely a lot less than the main heater!

The steering wheel heat is welcome, but frustrating. I understand the idea of a thermostat but the way it's implemented seems silly. Imagine if your home thermostat worked this way! :eek: :roll:
 
Nubo said:
...The steering wheel heat is welcome, but frustrating. I understand the idea of a thermostat but the way it's implemented seems silly. Imagine if your home thermostat worked this way! :eek: :roll:
My home thermostat does work this way: if the furnace ran continuously my house would rapidly overheat. I even have my thermostat programmed to have a wide temperature variation so that the furnace doesn't cycle on and off very often but runs longer each time it kicks on.

Consider that the steering wheel heater needs to heat up enough to be useful when the car is below 0ºF but not overheat if someone uses it at 55ºF. Given that large range, just having a resistance heater that runs continuously would be impractical. Having a resistance heater for such a tiny application that can vary temperature by adjusting current flow, or use multiple heating elements depending on temperature, would add complexity and cost. By comparison, a thermostat that turns the current on or off is pretty simple.

At least one person has already complained that it is "too hot"; barring an actual defect, I presume that if the steering wheel heater is "too hot" it is being used in conditions too mild for it to be needed.
 
dgpcolorado said:
Nubo said:
...The steering wheel heat is welcome, but frustrating. I understand the idea of a thermostat but the way it's implemented seems silly. Imagine if your home thermostat worked this way! :eek: :roll:
My home thermostat does work this way: if the furnace ran continuously my house would rapidly overheat. I even have my thermostat programmed to have a wide temperature variation so that the furnace doesn't cycle on and off very often but runs longer each time it kicks on.

Consider that the steering wheel heater needs to heat up enough to be useful when the car is below 0ºF but not overheat if someone uses it at 55ºF. Given that large range, just having a resistance heater that runs continuously would be impractical. Having a resistance heater for such a tiny application that can vary temperature by adjusting current flow, or use multiple heating elements depending on temperature, would add complexity and cost. By comparison, a thermostat that turns the current on or off is pretty simple.

At least one person has already complained that it is "too hot"; barring an actual defect, I presume that if the steering wheel heater is "too hot" it is being used in conditions too mild for it to be needed.

I understand the need for a thermostat. I'm just saying the wide temperature swings are neither necessary nor useful.

Most home thermostats have a maximum swing of 3 degrees or so. Going much larger is counter-productive because people start feeling drafts and turn up the heat to compensate. Going by feel I'd say this steering wheel heater has a swing of 30-35 degrees.

There is nothing complex or expensive about putting a feedback device in the loop. I imagine there already is a simple one, as you suggest -- to turn on and off at certain temperatures. It doesn't need to "adjust current flow", it just needs to turn on and off more frequently so that the swings are centered more closely around the mean. Why go from "too hot" to "too cold"? I want a comfortable steering wheel, not a "Goldilocks Device". :lol:

Driving for 10 minutes with a "cold" heated steering wheel seems ludicrous.
 
dgpcolorado said:
So far as I am aware it doesn't have a value for the heated seats or steering wheel heater, perhaps because they weren't on the first LEAFs and the algorithm wasn't adjusted for cars with the cold weather package.
That's correct. I'd be happy with that sort of estimate of usage. It's unfortunate that Nissan didn't include these values in the meter.
 
The aftermarket seat heaters I bought are rated something like 50-60 watts each...Noise in the scheme of 20,000-50,000 watt average traction battery usage...
 
LOVE the heated steering wheel!

As far as the pulsing, it reminds me of staying with my grandmother when I was a kid and having electric blankets on the bed. They would heat up, turn off and then heat up again. They weren't fancy enough to maintain a set temp, just a setting of how long they stayed on before cycling.

I find myself holding the top of the steering wheel as it warms up and working my way down as it gets hot and then working my way back up. Maybe it helps you stay awake?

Philip
 
Sorry for the threadjack, but has anyone noticed that your heated steering wheel turns off with extended use? I'm not talking about cycling on and off every few minutes- I mean it completely shuts down after several minutes of use.
 
Heated seats in general seem pretty efficent. As a point of reference here are the Volt's. (thanks for pauldon on gm-volt)

Low: 15 Watts - 33% duty cycle (30SecOn/(30+60))
Med: 30 Watts - 60% duty cycle (60SecOn/(60+40))
High: 45 Watts - ??% duty cycle
 
My 68 Mile round trip, I pre-heat the car before i leave. and use the Seat warmers. I find no change in using them or not using them on my commute. I agree with the cabin heater, it does draw some extra juice, I try not to use it if i dont have to, if the windows start to fog up I crack the front 2 for a few miles (takes care of the fogging) and bump the steering wheel and seat heater (on high). Pretty comfortable on my commute. Wish i had heated socks as low quarters and thick socks dont do justice.

Maybe with the new details of the MY 13 LEAF in japan (same battery longer range) might be a new programming option for previous model years allowing us to recieve the same benefits?!? It should be simple to reprogram the heater controller to suck less power (like an eco-eco-eco mode, severly less power than 2-4kWh...thats redicilous)
 
garsh said:
Has anybody measured the power draw of the heated seats or the steering wheel?

I think I'm noticing a decrease in efficiency when I use them, so I'm wondering if they aren't quite as insubstantial as I thought they were.

Are you using low or high? That could make a difference.
 
If the seat and steering wheel heaters are thermostatic controlled, then you really can't put too much weight on the current consumed at any one time. It will start high, then pulse on and off at a lower and lower duty cycle. As your seat and steering wheel heat up, it will reduce to a very low average current level because there is nothing really drawing out the heat.

By comparison, a normal cabin heater must constantly replenish lost heat through the glass and car body. The colder the outside air, the more heat lost.

That's the real difference in power used, not the DC current draw at any time.
 
Now I'm gone through a whole lot of manuals for the Leaf but couldn't find a list of fuses that tells which one is for those heater elements. Therefore I cannot measure the current it draws.
But anyway, the knowledge about the structure of the fuse box is essential for any car repair.
Is there anybody able to give an answer to that? Can't be too hard! ;)
 
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 (maybe not identical as there are two bottoms, no back-heaters).

Average consumption on trips is much lower because it is idling when it has reached the max.
Steering wheel is much less and that is cycling too.
 
Arnis is the greatest with a real measurements !

1.3 amps @ 13.8 V = 18 watts each seat on low
2.5 amps @ 13.8V = 35watts nominal each seat on high.

As was said.. 35 to 70 watts isn't even a drop in the bucket. .035 to .07 Kw

I am indebted to learn the energy display.. isn't really measuring anything..
just displaying assigned numbers.

That explains why the approx. 90 watt load of the front seat heaters and steering wheel don't make a blip
on the radar.. and neither do the "parking lights" ( amber bulbs in front and LED tail lights).
Simply not in the program.


Even at 40F.. I find the steering wheel "too hot"...a low/high option here would be nice.
but everything costs money except pushing the off button. :mrgreen:
 
Actually they totally failed with steering wheel heater element.
Many products can use self regulating heating wire. But not Nissan. Bad engineers working there :(
All they need is a to fill a checkbox at vehicle equipment list to get more customers.
That's been true pretty much for the whole Leaf.
 
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