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

[GlennD]

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.

[TomT]

Ah, OK; now I get what the note referred to... I always use static protection too so I didn't give that much thought...

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.

[aminorjourney]

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


and CN3.



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.

[fluxcap]

Thanks! Very useful information!

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)

[BetterLeaf]

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/pr ... 6c29hm.pdf" onclick="window.open(this.href);return false;

Other info:
http://www.renesas.com/products/mpumcu/ ... 0FATHP.jsp" onclick="window.open(this.href);return false;

[BetterLeaf]

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!

[iluvmacs]

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.

[pchilds]

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.

[DaveinOlyWA]

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

[aminorjourney]

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.