Easy Climate Control Fan-Only Solution - 5 cents, 5 mins

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BetterLeaf said:
I did a quick experiment. Preheated the car for about 10 mins. Outside temp was around 26F.

Here are some pictures that I took with a thermal imaging camera. All from the driver's side perspective.

Good stuff! I think the problem is the LEAF's liquid heating system was based on a traditional ICEv's heating system, where heat is an abundant waste product, so insulation is neglected for cost reasons.

I haven't been as active/attentive as I used to be but I believe the MY2013 LEAFs have done away with the liquid system entirely in favor of a heat pump + direct to air resistance heat, so this problem ought to be solved. Still, for current LEAFers this looks like a way to potentially increase the efficiency of their heating system, if only just a tiny bit, for negligible cost and effort.
=Smidge=
 
insulation might be a cost issue to Nissan but it aint for me. will be getting some pipe insulation today. wont be perfect, but betting its better than nothing!
 
Thanks for figuring this out! I've been wondering for a while if there might be an easy way to disable the heater with a simple switch. My use case is for preconditioning the car in the summer when my garage may not have warmed up to outside ambient temperature yet, this will often result in coming to a hot steamy car instead of a nice cool car with a fuller battery.

I also have wondered why exactly Nissan has their hot water flowing "all over" the engine bay without insulation. Will be interesting to see the before and after FLIR images :)
 
I just used my laser temp reader to confirm the temperatures shown in the thermal imaging camera.

No doubt about it, the heat loss is huge!

Nissan, should be ashamed of themselves.

It looks like we need a plan to insulate this system and save the heat!

Bill Matley
 
How about something like this?

http://www.pipelagging.com/c0tape-class-armaflex-tape-p-71.html?gclid=CNjq2-vZnrUCFdLMtAodyBAA0g" onclick="window.open(this.href);return false;

I also wonder if it's worth investigating if modifying the Leaf heating system to include a vacuum flask would help? Sure, it would increase the volume of water in the system, but wouldn't a larger body of water (some of which would be in the flask) stay warm for longer, helping reduce energy wastage when you stop for half an hour at the store or whatever?

I know the Prius has a flask to help the engine coolant stay warm between short stops. That reduces engine warmup time and improves energy efficiency.

Basic physics says that keeping something at a constant temperature is less energy than warming it up. So if we can minimize heat loss, we can improve efficiency, right? :)
 
aminorjourney said:
How about something like this?
http://www.pipelagging.com/c0tape-class-armaflex-tape-p-71.html?gclid=CNjq2-vZnrUCFdLMtAodyBAA0g" onclick="window.open(this.href);return false;

Not bad, but I think it is too thin. The thermal conductivity is per meter and it is only 3 mm thick. So the thicker the better.

I'm thinking a self adhesive insulation sheet like this would better:
http://www.pipelagging.com/armaflex...undproofing-sheet-selfadhesive-13mm-p-54.html

Cut it into strips and patches that can be easily applied. You need to cover both pipes in places. Some areas are hard to get to so you can only slap it on to prevent exposure to cold air. Where there is space two layers can be wrapped around.

aminorjourney said:
I also wonder if it's worth investigating if modifying the Leaf heating system to include a vacuum flask would help?

That's definitely not for me. Too many short trips with too much time to cool off. It takes more energy and time to heat more water.

I would have preferred if Nissan had used a solution without any water. Just put the PTC heater in the airflow. That's what many cars with diesel engines are using in areas with harsh winters.

Instant heat, no pump to break down, no fluid that can leak or evaporate.
 
I have received an email request for the 4016B schematic. Let me be clear, The idea was Betterleaf's. I just implemented his suggestion. The input filter is his. I removed the voltage divider and I depend on the installed circuit for input termination.

I mounted the circuit on a scrap of perf board. The connecting wires are #30 wire wrap wire. This wire fits through the PCB vias perfectly. I think it made a clean installation.

HeaterModSchematic_zps4c6727b2.jpg
 
Nice thermal pictures! A lot of Leaf owners here in Norway, eventually also me, have insulated the expansion tank and parts of the tubing. It definitely helps to save some energy, but accessing all the tubing is difficult, therefore I haven't done any more about this. However, last winter constant use of the heater did seem to reduce my range by about 10-20 km more than it does now at temperatures around -10 degrees C. However, I remember that I sometimes had 3 battery bars last winter, so far this winter it always has been 4 bars and battery temperature is certainly not affected by the insulation of the expansion tank or tubing and therefore might account for some of the range difference since the battery simply stores more energy this year than last year. I am sure that the insulation job I did helps, but still I suspect that the main heat loss is probably the heater itself, and I haven't found the heater because it seems to be hidden from the view. Would be interesting to have a thermal picture of the heater itself... In the winter time I don't need to regulate the heat element, but it will be nice to implement the possibility to switch of the heater next summer.
 
Thanks! Very useful information!

What kind of insulation did you use?

The PTC heater is located under the battery and is fully accessible if you remove the drivers' side front wheel and the front fender protector. To remove that the front under cover also needs to be removed.

If I remember correctly then you can at least see the heater without removing the wheel if you follow the user manuals instructions on how to change the fog lights/daylight running lights. That also explains how to remove these covers. Don't know if that's enough to put on some insulation. And careful, this thing is connected to the 400V battery.

Here are some interesting pictures:
Underneath the Beast; a Tour of the Dark Side
http://www.mynissanleaf.com/viewtopic.php?f=38&t=3896

This one shows the PTC heater. (Incorrectly labeled as "Cooling fluid goes in this. Maybe the coolant pump?")

IMG_0686.jpg
 
Hi Glenn,

Just curious about one thing on your version. There is a note on your schematic about a 10M resister but I can't quite decipher it. Could you elaborate?

I used the discrete component on vector board method since I had them all here already, but I installed mine on the component side of the board since it looked neater and I had more clearance...

Nice idea on using the 4016!

Thanks!

GlennD said:
I have received an email request for the 4016B schematic. Let me be clear, The idea was Betterleaf's. I just implemented his suggestion. The input filter is his. I removed the voltage divider and I depend on the installed circuit for input termination.
 
The ic input is floating until it is installed. Then the 12V supply effectively terminates the input. The 10M resistor would terminate the uninstalled circuit. In my case I used a socket and installed the chip after I wired the circuit.

I work with an anti-static mat on my bench and a wrist strap so static is not a concern.
 
Ah, OK; now I get what the note referred to... I always use static protection too so I didn't give that much thought...

GlennD said:
The ic input is floating until it is installed. Then the 12V supply effectively terminates the input. The 10M resistor would terminate the uninstalled circuit. In my case I used a socket and installed the chip after I wired the circuit.
 
I've just opened up my Leaf (UK spec, made in early 2011) with a friend to plan the mod, and to check that my board was the same as the US ones.

While my board shares the same revision number and components,it does have two extra connectors I've not seen here...

CN2

8461920796_5b1c8d95f7_c.jpg

and CN3.

8460822461_94162f9ac8_b.jpg


I assume they're for debugging and/or programming. But as my Leaf is a fairly early one (one of the first few in England) I think the connectors may have been initially put on, but then removed for cost reasons.

Anyone have any ideas what they are? And why some of us have them, and some don't?

The mod itself will happen some time in the next few weeks. Best to take our time, rather than screw it up!

Nikki.
 
BetterLeaf said:
Thanks! Very useful information!
IMG_0686.jpg

It would be very interesting to see some winter tests with the PTC heater insulated. I have measured the outside temperature of the PTC heater to 60 degrees Celsius. It looks like its made of metal, with circulating water on the inside and cold wind blowing from the outside, I suspect a major heat loss from this unit.

I did this test on my Leaf:

AC Off
Temperature set to Maximum
Fan set to minimum (Level 1)
Mode set to Window/Legs

At ca. 0 degrees celsius and 0 km/t I see a usage of ca. 1,5 kw (Ie the regulator reduce the effect due to the fact that the max temp is reached inside PTC)
At ca. 0 degrees celsius and 90 km/t I see a usage of ca. 2,5 - 3 kw

This I read as the heating system loose more than 1 kw due to wind cooling of the heating system.
(The uninsulated PTC unit I think is one of the major parts in this loss)
 
aminorjourney said:
I assume they're for debugging and/or programming.
Anyone have any ideas what they are? And why some of us have them, and some don't?

Thanks for posting those pictures. Very helpful.

Yes, they are most likely for debugging or probing. CN2 connects to the microcontroller's serial port 1. CN2 Pins 1 thru 4 are mapped to the processors pin 31 thru 27. So Pin 4 is TxD1 and Pin3 is RxD1. One of Pin 5 or 6 must be GND.

Anyone up for a level-shifter on TxD to see if there is any interesting output? :)

BTW One of the microcontroller's serial ports is used to talk to the A/C compressor. Before any probing is done it should be ruled out that TxD does not just connect to Pin 14 of the M50 connector.

I could not trace CN2 completely from my pictures. I would need the board in front of me. Pin 1 goes near the processor though. 2/3 are probably VCC/GND.

BTW the processor is a M30290FATHP
from the Renesas M16C Tiny series.

16 bit 20 MHz Microcontroller
96K Code Flash
4 K Data flash
8K RAM

Input timer : 3
Output timer : 5
Input capture : 8
Output compare : 8
10-bit A/D converter : 24ch (80pin)
Serial I/O : 5
Watchdog timer : 1
3-Phase Inverter control : 6
Multi master I2C-bus
CRC calculation circuit
PLL
CAN : 1ch

Packaging is a 80P6Q

Hardware manual:
http://documentation.renesas.com/doc/products/mpumcu/rej09b0101_16c29hm.pdf" onclick="window.open(this.href);return false;

Other info:
http://www.renesas.com/products/mpumcu/m16c/m16ctiny/m16c29/device/M30290FATHP.jsp" onclick="window.open(this.href);return false;
 
fluxcap said:
This I read as the heating system loose more than 1 kw due to wind cooling of the heating system.
(The uninsulated PTC unit I think is one of the major parts in this loss)

It really hurts but it certainly appears that way. Thanks for sharing this!
 
I completed installing this circuit on my '12 Leaf today. My most convenient transistor was a BSS138, which has significantly different enough a gate threshold voltage that I had to adjust the divider. The first time I tried it, it was inconsistently overriding the climate control. I changed the 220k resistor to a 1M resistor, and now it is fine (probably a "safer" value in terms of being compatible with more transistor models).

Also, my car decided to light the EV warning light upon first power up both times I took the ECU out of the dash and put it back. A restart took care of that both times. Note thad I did not have the defrost LED blink upon power-up as you suggested... so perhaps some firmware versions have different behaviors. I did not power up the car with anything disconnected.

Thanks so much for posting this! A big help here in Wisconsin winter, and a lot less cost than buying the mod.
 
Thanks for the post, I went with method #2. Now I won't have to keep changing the set temperature to keep the heater off, when I need AC.
 
back to the national smart grid. it was part of Obama's plan derailed from the banks, housing, etc. crash. sounds like an investment in the infrastructure would go a long way towards rebuilding a solid financial foundation here.

Roosevelt did it albeit not perfect and I think its time for another large project except this time towards greener and better energy management
 
Just an update from over the pond ;)

I can confirm that this mod -- with the 4016 chip -- works fine in UK spec 2011/12 Nissan Leafs.

Thanks to my friend John (my soldering skills aren't up to me trusting myself to modify the heater circuits on my £25,000 car) I now have the modification working a charm :)

I've got lots of driving next week, including an early morning run to the airport and back, an 80-mile round-trip to Cardiff, and a 240 mile round-trip to London. I'll let you know if the mod lets me keep the screen clearer without using any heating and increase my cruising speed.

Thanks to everyone who has helped devise this mod!

Nikki.
 
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