Transmission coupling

Just bought a red 2015 Leaf SL for my wife last week.

She is having a hard time getting her hands on it at present

Lot of new terms to learn and things to understand.

It was a good Nissan dealer ( Alta ) just north of Toronto, but they were not very knowledgeable about the finer points of the Leaf, even though they were delivering three Leafs to customers and only one ICE that day!

They told me it had run flat tires ( not ).

They also told me it has a viscous coupling ( clutch?) between the motor and the wheels, so that when you step on the brake, the motor is still turning. Not sure this is true. But it has me pushing the park button when sitting in traffic at a stoplight, to save energy.

Some little things I have learned:
There is a back up beeper.
It has a built in heat pump for the heat and AC that is apparently much more efficient than resistive heat alone.
There is extra insulation in the roof to keep in heat.
The rotors are ventilated like a sports car.
An OBD reader will not work in the OBD port.
The acceleration off the line is way better than expected!!
The horn sucks, sounds like you stepped on a chipmunk.
There is risk of freezing and destroying the battery, so you need to keep it plugged in during those cold Canadian winter nights.
Telematics with a cellular connection is cool, but why can't we do some diagnostics through this connection?
Drain the car below 30% and it will not completely recharge overnight during our off peak rates ( 7PM-7AM), with the included charger.

Sorry for the ramble. I really want to know the details of the coupling from the motor to the wheels, and what the gear selector really does.

Thanks

Kev

I believe that the Leaf has a fixed gear ratio transmission between the motor and the wheels. There is no slip mechanism, no clutch, and no shifter. When you put on the brake, you stop the motor. The motor still gets a tiny amount of energy so that when you let your foot off the brake, it inches forward slightly. This gives you the general feel that you're in drive and is supposed to minimize the risk of you going backwards without knowing it.

The gear shifter only affects software, controlling power to the motor. Think of it as a mouse rather than a gear shift. Many people advise against putting it into neutral, just because it makes it harder to move in an emergency and prevents the regeneration system from slowing down the car on downhills. Neutral going downhill is actually illegal in some places.

I bought a bluetooth OBD-II adapter for ~$10 and use it with a program called Leaf Spy Pro to tell me all kinds of cool things about the car, such as tire pressure, battery temperature, battery cell voltage, and battery capacity. The Leaf Spy Pro program is not expensive, only $15 and very worthwhile. The author supports his work, too. There is a Leaf Spy Pro discussion list here, too, for even more support.

During those cold Canadian nights, if the battery gets cold enough, it will activate its own heater. So you don't need to worry about it freezing. But that heater will slowly drain your battery, so it doesn't hurt to have it plugged in on those cold nights.

However, DON'T LEAVE IT PLUGGED IN FOR WEEKS! There's a silly bug in the system so that when the Leaf is plugged in, the 12V battery will not get topped off by the traction battery, and the 12V battery will slowly bleed down. If you do not have the Leaf plugged in, the traction battery will top off the 12V battery every few days and the car can sit idle for months safely.

I hope that this helps.

Bob

None of it is true.

Euthanasia of dealers should be legal!

kmartyn said:

They told me it had run flat tires ( not ). They also told me it has a viscous coupling ( clutch?) between the motor and the wheels, so that when you step on the brake, the motor is still turning. Not sure this is true.

Click to expand...

kmartyn said:

... They also told me it has a viscous coupling ( clutch?) between the motor and the wheels, so that when you step on the brake, the motor is still turning. Not sure this is true. But it has me pushing the park button when sitting in traffic at a stoplight, to save energy.
...
An OBD reader will not work in the OBD port.
...
There is risk of freezing and destroying the battery, so you need to keep it plugged in during those cold Canadian winter nights.

Click to expand...

No viscous coupling. Single ratio transmission that reduces motor RPM.
Once you are stopped and foot is on brake motor is at zero RPM so no energy savings by putting it in Park.
Putting it in Park in traffic is a bad idea as it can occasionally be a little finicky about going back into Drive.
There is built in forward and reverse creep but only turns on with brake released.

OBDII port works you just need the correct readers. See LEAF Spy for android devices that works with Bluetooth ELM adapters. Are also WiFi adapters and apps for Apple devices.

LEAF has battery heater. Not much power and will protect battery a fairly long time even if not plugged in.
Just don't leave it outside in extreme cold for long periods, several days, without charging.

It does nothing more than send an electrical signal to the motor controller to tell it what mode you want to be in. The park button, which also just sends an electrical signal, selects electrical neutral and drops a pawl in to the gear in the transmission (really just a transfer case) to mechanically lock it, much like park works on an ICE with an automatic...

kmartyn said:

I really want to know what the gear selector really does.

Click to expand...

Bob said:

Neutral going downhill is actually illegal in some places.

Click to expand...

The Leaf technically can't be put into neutral. It's fixed into gear, and this is the primary reason the drive wheels must be off the ground when towing. I doubt that argument would hold up in court, but if you hired a reasonable lawyer, I'm sure you could get away with it. That said, I've never heard of anyone getting this ticket, and I have no idea how they could prove it.

Usually it's a bad idea to go downhill in neutral, or even an emulated neutral. Just feather the accelerator to control speed.

A transmission, by definition, must have the ability to vary the input/output shaft speed ratio. The Leaf does not have a transmission. I have heard the gearbox referred to as a "one-speed transmission", but that would be an oxymoron.

As for leaving it plugged in on cold nights...if you are using the 120 volt charging cable (aka "EVSE", not "charger") supplied by Nissan, and the car will be charging all or almost all night, that's a great idea. If you have a 240 volt level 2 EVSE installed at home, however, the car may stop charging many hours before dawn, and start to drain the accessory battery because it keeps verifying that it's plugged in - one of Nissan's Goofs with the cars. In that case try to time it so the car isn't plugged in but not charging for more than several hours, especially in really cold weather. If you can't avoid that, add a 12 volt battery maintainer to compensate for the accessory battery drain. Look for one that provides at least 1.5 amps.

garymelora said:

A transmission, by definition, must have the ability to vary the input/output shaft speed ratio. The Leaf does not have a transmission. I have heard the gearbox referred to as a "one-speed transmission", but that would be an oxymoron.

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Incorrect.
Per the Oxford dictionary:
"The mechanism by which power is transmitted from an engine to the wheels of a motor vehicle."
Of course for the LEAF, it is:
The mechanism by which power is transmitted from the motor to the wheels of the vehicle.
A transmission can be single speed, it is in the LEAF.

But I do agree the more commonly used nomenclature for it is a single speed gear box.

Dealers....

Very helpful, thanks for the information.

I will check out leaf spy, as soon as I figure out how to search on this site.

Kevin

Kevin,

http://www.mynissanleaf.com/viewtopic.php?f=44&t=14285" onclick="window.open(this.href);return false;
https://play.google.com/store/apps/details?id=com.Turbo3.Leaf_Spy_Pro&hl=en" onclick="window.open(this.href);return false;

The easiest way to search the forum is to just use a normal google search and include "Nissan Leaf" in your search field. Google will search this forum as well as any other sites that cover the leaf.

You'll also see someone going by the name "Turbo3". That's the person who wrote the Leaf Spy programs.

Bob

> I will check out leaf spy, as soon as I figure out how to search on this site.

Don't go there for service. If really have to, make sure the tech won't try to clean your injectors.

TimLee said:

garymelora said:

A transmission, by definition, must have the ability to vary the input/output shaft speed ratio. The Leaf does not have a transmission. I have heard the gearbox referred to as a "one-speed transmission", but that would be an oxymoron.

Click to expand...

Incorrect.
Per the Oxford dictionary:
"The mechanism by which power is transmitted from an engine to the wheels of a motor vehicle."
Of course for the LEAF, it is:
The mechanism by which power is transmitted from the motor to the wheels of the vehicle.
A transmission can be single speed, it is in the LEAF.

But I do agree the more commonly used nomenclature for it is a single speed gear box.

Click to expand...

After some further research I acknowledge that there is such a thing as a one-speed transmission, but I still think it sounds silly. So now I wonder, is the Leaf transmission a manual or an automatic?

garymelora said:

... So now I wonder, is the Leaf transmission a manual or an automatic?

Click to expand...

The terminology manual or automatic is meaningless for a single gear ratio transmission as there is no changing of gear ratio.

TimLee said:

garymelora said:

... So now I wonder, is the Leaf transmission a manual or an automatic?

Click to expand...

The terminology manual or automatic is meaningless for a single gear ratio transmission as there is no changing of gear ratio.

Click to expand...

It is not manual or automatic in my mind. Transmission is just a single ratio reduction gearbox.
Often it is called automatic because it works without driver intervention.