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Re: cabin heater, how does it work?

Posted: Sat Nov 18, 2017 3:34 am
by spirilis
Carbuff wrote:Its starting to get cold around these parts. Im starting to use the heater a bit more. How does the heater work? I find that it blows cold for like 2 minutes before getting warm. I guess its not an open electrical element with air blowing past it (like a blow drier) because that would give me almost instant heat. Is it a closed liquid system where the liquid is heated by an electric element? I could see this requiring some time to heat the liquid before feeling hot air. Also, I can drive the car all day without turning on the heat and when I do turn it on it still takes time to get warm. unlike an ice vehicle that makes heat even if you dont have it turned on. How does this system work?
You got it... the HVAC heater has its own coolant loop but I think it can "mix" with the motor & battery loops if the computer allows? I guess that can slightly pre-heat it if the heater's not been used but you've been driving a while. Otherwise, there's a PTC coolant heater that draws about 6+kW that needs to heat the coolant.

From what I've seen (using FORScan Lite over a bluetooth OBD-II dongle) when used in normal heat mode, non-defrost, the heater coolant loop targets ~130F temp, but when you kick on the defrost mode, the target temp rises to ~150F. So if you ever have the heater on, then kick on the defrost mode and watch the climate power consumption shoot way up again, that's why.

As an aside, in the MyView mode on the left instrument cluster display, there is a display mode where you can see the real-time power consumption of the climate control and "Other" (12V DC-DC converter and maybe other components).

Re: cabin heater, how does it work?

Posted: Sat Nov 18, 2017 3:50 am
by spirilis
See http://www.myfocuselectric.com/forum/vi ... =15&t=4027 - jmueller065 offered a PDF that explains the coolant loops

edit: 404!

Re: cabin heater, how does it work?

Posted: Sat Nov 18, 2017 6:51 am
by jmueller065
spirilis wrote:See http://www.myfocuselectric.com/forum/vi ... =15&t=4027 - jmueller065 offered a PDF that explains the coolant loops

edit: 404!
Yeah, sadly dropbox switched their policy and all my stuff in the public folder went offline.

Haven't found another place to host all that yet.

Re: cabin heater, how does it work?

Posted: Sat Nov 18, 2017 11:51 am
by spirilis
Carbuff wrote:
spirilis wrote:
Carbuff wrote:Its starting to get cold around these parts. Im starting to use the heater a bit more. How does the heater work? I find that it blows cold for like 2 minutes before getting warm. I guess its not an open electrical element with air blowing past it (like a blow drier) because that would give me almost instant heat. Is it a closed liquid system where the liquid is heated by an electric element? I could see this requiring some time to heat the liquid before feeling hot air. Also, I can drive the car all day without turning on the heat and when I do turn it on it still takes time to get warm. unlike an ice vehicle that makes heat even if you dont have it turned on. How does this system work?
You got it... the HVAC heater has its own coolant loop but I think it can "mix" with the motor & battery loops if the computer allows? I guess that can slightly pre-heat it if the heater's not been used but you've been driving a while. Otherwise, there's a PTC coolant heater that draws about 6+kW that needs to heat the coolant.

From what I've seen (using FORScan Lite over a bluetooth OBD-II dongle) when used in normal heat mode, non-defrost, the heater coolant loop targets ~130F temp, but when you kick on the defrost mode, the target temp rises to ~150F. So if you ever have the heater on, then kick on the defrost mode and watch the climate power consumption shoot way up again, that's why.

As an aside, in the MyView mode on the left instrument cluster display, there is a display mode where you can see the real-time power consumption of the climate control and "Other" (12V DC-DC converter and maybe other components).
Interesting, So will my heat get hotter faster if I have it set to max defrost? I figured it used more power because it turns on the rear window defroster too, which draws quite a bit. Also, the other day when it got down in the high 20,s, I got a message that said it was cold outside and to plug the car in. Im guessing this was to keep the battery at the desired temp? I got this message after shutting down in my drivewaY after driving around a bunch.
The heat won't show up faster, and keep in mind a lot of the heat during defrost will be lost through the windows, but if you run defrost long enough that the climate power consumption drops below 4kW or so and then suddenly turn off the defrost (so it's in AUTO mode) the heat may come out hotter.

For a short while anyway. PTC heater will shut off when you switch away from Defrost. Eventually the coolant will chill back to 130F until the PTC heater kicks back on.

Re: cabin heater, how does it work?

Posted: Sat Nov 18, 2017 1:11 pm
by jmueller065
Try this link for how the heating/cooling system works:
https://www.dropbox.com/s/6vpsdoelmahhr ... m.pdf?dl=0

Re: cabin heater, how does it work?

Posted: Sun Nov 19, 2017 7:23 pm
by JTCalif
jmueller065 wrote:Try this link for how the heating/cooling system works:
https://www.dropbox.com/s/6vpsdoelmahhr ... m.pdf?dl=0
Thank you ... good link.

Are there other lessons in the series?
Where could people look for such??

Re: cabin heater, how does it work?

Posted: Mon Nov 20, 2017 4:09 am
by jmueller065
JTCalif wrote:
jmueller065 wrote:Try this link for how the heating/cooling system works:
https://www.dropbox.com/s/6vpsdoelmahhr ... m.pdf?dl=0
Thank you ... good link.

Are there other lessons in the series?
Where could people look for such??
There are two other "lessons":
https://www.dropbox.com/s/7ntqla4hnlyb9 ... w.pdf?dl=0
https://www.dropbox.com/s/8lvntvvoc4x6v ... m.pdf?dl=0

(Don't remember how I found all those--likely some arcane google search--found one and then discovered the other two.)