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PostPosted: Wed Nov 28, 2018 1:28 pm 
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Location: Toledo, Ohio
Now that the price on these things have come down to almost 1/2 what they were 3-4 years ago when I first pondered this. I am again contemplating adding a parking heater. I likely won't get to it before spring so it would be for next winter but I figured I'd start this thread to flesh out some ideas and options to come up with the best solution for me. Originally I was looking at a propane solution so I could use the simple 1 pound propane canisters. Apparently these things don't exist so I decided on diesel since it's much safer than gasoline. I haven't dug too deeply into the details yet but I'll update as I do. If anyone has knowledge or information on exactly how the electric heater works I'd greatly appreciate it. I do have wiring diagrams I'll be taking a look at.

I figure there are two ways to accomplish this:
1) liquid parking heater that takes the place of the electric unit. This is the more expensive yet preferred method if it can be installed such that it can use the electrical signals that would have been sent to the electric heater. I don't know how the OEM heater works other than it supposedly uses a PTC resistive heater element. From the dash power monitor you can see that once up to temp the heater power slowly pulses up and down. The question is this due to some temperature regulation internal to the heater or does the car have a temp sensor and it commands the heater to pulse on and off. If the car is sending control signals to the heater, what are they? Is the OEM heater a binary on/off device or is it capable of throttling heat output? I also wonder if the car uses the cabin heater coolant loop for the battery too under any conditions.

2) air parking heater either run thru the firewall or installed in the rear hatch and exhausted out the rear hatch floor. Likely option if I can't make the liquid heater work. Also far cheaper, easier to implement and likely noisier option. I also would worry about potential CO leaks. Definitely would want to use a 12V or battery powered CO detector. I suppose you could also rig up a temporary frame to sit in the back seat and exhaust out one of the rear windows but that would be really janky and potentially extremely hazardous in a crash.

I am interested in any input that will help this project along. I vaguely remember reading about something similar on the I-MiEV forums to this: https://insideevs.com/video-utilizing-a-combustion-heater-in-a-fully-electric-car-an-users-story/

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PostPosted: Wed Nov 28, 2018 2:31 pm 
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Joined: Tue Feb 12, 2013 4:36 am
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Location: Southeastern MI
If you don't already have this guy, take a look. It describes all the cooling (and heating) loops in the FFE (in general terms but it sounds like this is more info than you already have).

https://www.dropbox.com/s/6vpsdoelmahhr ... m.pdf?dl=0

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2014 Sunset Escape
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PostPosted: Thu Nov 29, 2018 4:52 am 
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Joined: Tue Aug 16, 2011 11:40 am
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Location: Toledo, Ohio
Thanks that was one of the things I had but it's been a year or so since I've reviewed it. Problem is it doesn't give too many specifics but it gives just enough info to give you hope that it just may be possible... One thing I just though of is, would you use the fluid pump that came with the heater or keep the OE pump. If you keep the OE pump, what triggers the OE pump so you can avoid having the heater on without the pump. Who knows maybe the parking heater has an internal tstat to turn off the flame if the liquid gets too hot. Although relying on something like that seems like it would be an eventual recipe for disaster.

Looks like i have some studying of wiring diagrams, the above coolant loop info, and some testing to see if I can wrap my head around how it works. Once I figure out how it works I should be able to quickly figure out if one of the commercially available coolant heaters can be made to work in the electric heater's place.

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PostPosted: Thu Nov 29, 2018 6:53 pm 
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Joined: Thu Aug 11, 2016 3:31 pm
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Just a crazy thought.....

Maybe steal the heat storage block and coolant pump out of one of these

http://www.steffes.com/electric-thermal ... oom-units/

and connect it to the FFEs heater core. Feed the heating elements off of 120v grid electricity overnight. Run the coolant pump via the 12v with an inverter and manual (or thermostat) switch and use the FFE's blower in manual mode with the FFE thermostat set to LO.


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PostPosted: Fri Nov 30, 2018 4:04 am 
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Joined: Tue Feb 12, 2013 4:36 am
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Location: Southeastern MI
If I did it I would want my mod to mimic whatever the FFE is expecting that PTC heater core to do.

I'd disconnect the high-voltage cable and use the control wires to turn on/off my new "heater" and let all the FFE's electronics do what they were going to do--including running the coolant pump.

I'd start out by trying to figure out what those control cables are? Are they simple on/off? PWM? a CAN bus? Might be instructive to get that part from a junk yard and disassemble it.

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2018 Cajun Red Chevy Bolt
2016 Magnetic C-Max Energi (lease returned)
2014 Sunset Escape
2014 Thor Axis (V-10)
2013 Focus Electric (lease returned Jan 2016 for the C-Max above)
https://spareelectrons.wordpress.com/


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PostPosted: Fri Nov 30, 2018 5:09 am 
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Joined: Tue Aug 16, 2011 11:40 am
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Location: Toledo, Ohio
jmueller065 wrote:
If I did it I would want my mod to mimic whatever the FFE is expecting that PTC heater core to do.

I'd disconnect the high-voltage cable and use the control wires to turn on/off my new "heater" and let all the FFE's electronics do what they were going to do--including running the coolant pump.

I'd start out by trying to figure out what those control cables are? Are they simple on/off? PWM? a CAN bus? Might be instructive to get that part from a junk yard and disassemble it.

Exactly what I was thinking. Pretty sure there aren't any FFE heaters available from scrap yards around us. I figure I need to find a way to Non-destructively probe the signals going to the heater control wires. Also curious if the HV wires are always hot. I'd be surprised if they weren't but that's another thing I'd want to verify. Unfortunately I won't have any time for the foreseeable future to pursue this project.

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PostPosted: Thu Dec 13, 2018 1:42 pm 
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Location: Toledo, Ohio
So I found myself not being able to sleep last night and decided to do some digging.
So according to the document below the max PTC heater temp is 179F and the coolant pump circulates at 17.5L/min
Lesson-3-Cooling-System.pdf
I'm currently looking at the YJH-Q5A 5kW diesel parking heater
YJH-Q5A manual available here
I believe this is the model they are selling on amazon:
In the user questions the seller states that it can heat the water up to 75C (167F). Also the YJH-Q5A manual linked above states a minimum of 400L/h flow rate and the included pump is approximately 900 L/h.

So Far so good:
FFE heater loop max temp = 179F, Flow rate 17.5L/min (1050L/h)
Diesel parking heater max temp = 167F, min Flow = 400L/h nominal pump flow = 900L/h


I think I now have a pretty good idea of how the OEM heater works. looking at some electrical diagrams it appears to have a 40A fuse in the HV junction box (located on the top of the TCM). I would simply pull this fuse and figure out a way to seal up the plug and fake the HV safety circuit that would detect a cut HV wire. This should be simple enough since the safety circuit is just a closed loop. As long as it doesn't see a break in the circuit, there will be no fault. Now if anyone knows where I can get a salvage PTC heater HV wire harness I would greatly appreciate you letting me know. Or better yet where I can buy on of the connectors so I can make my own dummy plug to keep the HV plug clean and corrosion free in case I ever want to go back to using the electric heater.

Digging further into electrical diagrams I found this connector pin out:
Image
The connector pins show a ground, control mod, and enable. That looks promising I assume the enable is a 12V signal. Not sure what "control mod" means. Although watching the climate power graph on the dash, it does appear that the electric heater isn't simply on/off but can throttle it's heat output. That could be problematic.

Also found this wiring diagram for the low voltage wires on the PTC heater:
Image
This was a lot more helpful. Yep the enable is a 12V signal as I suspected. Also the "control" wire appears to be a simple pulse with modulation (PMW). Yay this something I actually may be able to work with. I am going to guess it's probably 0-12V or something like that. This is really encouraging as I know the diesel parking heater does throttle between 2.5kW output and 5kW and I believe it does this with PWM! If I end up having to use it's controller it does have a low, medium, and high output setting. Although if I can't get the parking heater to work with he PWM I should be able to plumb in the parking heater's own temp sensors and just set the parking heater to control to a set temperature and just have the diesel heater turn on and off with the 12V enable signal. I'm beginning to think this might actually work!

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