BTW, TDI, this is effing brilliant...
Hi all, 1st time posting to ask a question.
What is the watt rating of the resistors you used?
Would +/-2% tolerance work? You used +/-5% tolerance, no?
And thanks for your libertarian, with a small "l", perspective
@TDIwyse , I have data for you
I used an Omega HH82 dual thermocouple digital thermometer, one thermocouple measured interior ambient, one measured the A** Interface Temperature, typically abbreviated as AIT.
The type of thermocouples used were fast read film type, (Type K), pictured, very low thermal mass for minimal error contribution.
Why not use a thermal camera? Because a thermal image has no relevance to the desired measurement, with a thermal camera you are measuring the surface temperature of a poor thermal conductor being convection cooled. By using the thermocouple and placing it in the back jeans pocket, at the optimal A** to Seat contact position, we can measure the interface temperature or AIT, directly perceived by the driver occupant.
Test conditions and measurements:
The Bolt drivers side seat heater was turned on to high and the temperature was allowed to stabilize for the duration of 2.5 radio airplay rock songs, or about 10 minutes.
Outdoor ambient as reported on Bolt display 40F
AIT = 107.5
Internal cabin ambient 70.5
Subject was a 165Lb male wearing levi 505 jeans.
And yes, I can only run my stock Bolt LT seat heater on high for a very short duration before I need to reduce the power level to avoid the dreaded "seat heater swamp A**" condition that would result.
But I will test this additional measurement approach with a similar method you used to compare to the results I got with the thermal gun and report back.
It looks like there are two thermistors on the passenger side and one on the drivers side. Am I reading this correctly? If so, do you know why this is?
Just added pics to the photo link showing the same (<0.5 deg off) measured temperature with a thermometer probe placed between my back and the seat and with the heat gun (when done on roughly the same location and immediately after getting out of the seat). Both were between 98 and 99F. I've got to leave in 5 minutes, so I didn't have time to let the seat get up to full temp, but this shows that the heat gun on the Premiere leather seats gives the same results as a thermometer probe...
Thanks. I realize the schematic is for the Cruze. I was just trying to understand what I was seeing (so that I can understand the system in general better). Thanks for your thoughts on the reasoning behind what is shown. That helps.The Bolt has 2 thermistors for each front seat based on my testing. I'm not sure why GM, with the Cruze implementation, would have taken a short cut and just used one thermistor for controlling temps of both heating elements on the driver seat, but I'm guessing it was for cost/simplicity reasons.
Drove to work this morning so I had more than enough time to get the seat temps up to their steady state temp, and also used the thermometer probe to measure the temp. Added pic to the photo link. With the probe placed in the lower small of my back between my big fluffy winter parka and the seat surface, it was fluctuating between 117-118F max temps. This is very close to heat gun results, although they were a little lower because the surface will cool off quickly when getting out of the seat and turning around to start taking measurements... but if you're quick and accurate with your gun you can get good resultsJust added pics to the photo link showing the same (<0.5 deg off) measured temperature with a thermometer probe placed between my back and the seat and with the heat gun (when done on roughly the same location and immediately after getting out of the seat). Both were between 98 and 99F. I've got to leave in 5 minutes, so I didn't have time to let the seat get up to full temp, but this shows that the heat gun on the Premiere leather seats gives the same results as a thermometer probe...
Our LT should be out of the body shop today or tomorrow. I’ll do some tests when we have it back.If anyone else could find time to do some measurements, I at least would find it interesting to see if there's a significant variation in max seat heat temps, or if the Premiere's just have lower max heat from the factory.
This would be the mode I'm most interested in. Would you be able to take some temperature measurements and reply back? I think we're to the point where we don't need pics, although please add those if you can. However it would be good if at least some discussion of how the measurement was taken, what was the measurement device, and waiting long enough so the seat has time to stabilize at its max temperature....
3 light manual mode - take about 20 min to really feel warm if the weather is cold enough to want heated seats in the first place.
I don't have any hard data like temperature measurements to share, but in manual "3-dot" mode the seats in my 2017 Premiere become too hot for me within 5 to 10 minutes and I have to turn them down to the "2-dot" level. I agree that automatic mode is completely inadequate.I would propose that the pattern starting to develop is: Premier = not hot enough seats, LT = hot seats, yes?