Safety HV Disconnect?

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Yanquetino

Well-known member
Joined
May 11, 2010
Messages
479
I know that the RAV4-EV has a high voltage disconnect behind the driver's rear seat:

disconnect_rav4ev.jpg


The Mini-E also has one in the cargo area on the left side:

disconnect_minie.jpg


I believe that the EV1 likewise had such a switch, but I am not sure where it was located.

My question is: will the Leaf have one? If so, where will it be located?

It seems to me that it is an essential safety feature for emergency personnel who arrive on the scene of a serious accident involving an EV.
 
The EV1 disconnect is behind the passenger seat back. Pictures 13-15 here.

There appears to be a plug on the top of the Leaf pack roughly under the rear foot well tunnel area. That's my guess for the traction pack disconnect.

disconnect.jpg


leafplug.jpg


edit: Washington Post image disappeared. Found sheet-metal cut-out image from Nissan.
 
AndyH said:
There appears to be a plug on the top of the Leaf pack roughly under the rear foot well tunnel area. That's my guess for the traction pack disconnect.
AndyH: I think you're right! That sure looks similar to the RAV4-EV's disconnect plug.

We can also see it in this cutaway photo, with its plastic housing above the battery cover:

disconnect_leaf.jpg


Now I wonder how to access that plug. Would you have to pull the carpet off the rear tunnel in back?

disconnect_leaf_tunnel.jpg


My guess is that it might actually be accessible from the very bottom and rear of the armrest storage bin:

disconnect_leaf_bin.jpg


At least it's good to know that there IS a way to disable the traction battery entirely.
 
Shouldn't it be accessible to emergency personnel located closer to the "exterior" of a (smashed) car ? (Notice how in some accidents the occupants need to be "cut out" ... how do you get in there and pull the switch ?) Wouldn't a better location be under the hood or trunk -- which, if heavily damaged, is often "popped up" ?
Is this "disconnect" the same as or related to the SRS disable that emergency personnel needs to get to ?
 
I wondered about some sort of mechanical cable system to a couple different places to pull the disconnect. So if one part of the vehicle was damaged or inaccessible after an accident you could access a cable pull from another place.
 
At the front, the two big red connectors would be the battery pack's Plus and Minus, which would be about 350 volts DC, designed to carry something like 250 amps (85 kW capable).

The little white connector would be pack-status communication?
 
garygid said:
At the front, the two big red connectors would be the battery pack's Plus and Minus, which would be about 350 volts DC, designed to carry something like 250 amps (85 kW capable).
Since the front seats are positioned on top of the front battery modules, those two big red connectors appear to be in a fairly inaccessible location underneath the shifter "mouse" in the center console. My guess is that they are the prime connection between the battery pack and the controller/chargers...?
 
Yes, they are certainly representing "the" motive power connection.

The "Production" connections might be different, to better support pack service, swapping, or replacement.

There might be a seperate 12v power into the battery pack, to power the pack's internal electronics.
 
This bring up another question. Take the recent media hype about runaway Toyota vehicles with their gas pedal issues or whatever. Well, first of all, I thought that was mostly retarded because anyone who doesn't know about putting a car into neutral or turning it off doesn't need to be behind the wheel of a car.

However - this is something we should seriously think about with the Leaf. As far as I know, it has no transmission to put into neutral, right? I've also always been told that with do-it-yourself electric cars there is always a small change the motor controller could fail, and fail in a way that was supplying constant power to the motor without being able to shut it off. Although the battery pack is generally connected via a relay which is controlled by the key-switch, there is a possibility that if the current is high enough the relay may not be able to disconnect.

So Nissan needs to be sure to provide us with the means, and the education to be able to stop the Leaf in the event of a stuck throttle or motor controller.
 
adric22 said:
This bring up another question. Take the recent media hype about runaway Toyota vehicles with their gas pedal issues or whatever. Well, first of all, I thought that was mostly retarded because anyone who doesn't know about putting a car into neutral or turning it off doesn't need to be behind the wheel of a car.

However - this is something we should seriously think about with the Leaf. As far as I know, it has no transmission to put into neutral, right? I've also always been told that with do-it-yourself electric cars there is always a small change the motor controller could fail, and fail in a way that was supplying constant power to the motor without being able to shut it off. Although the battery pack is generally connected via a relay which is controlled by the key-switch, there is a possibility that if the current is high enough the relay may not be able to disconnect.

So Nissan needs to be sure to provide us with the means, and the education to be able to stop the Leaf in the event of a stuck throttle or motor controller.

Yeah... and it should be a mechanical hard disconnect, not some stupid thing through a touch screen interface on a computer connected to a bunch of sensors and actuators with hundreds of points of failure.
 
adric22 said:
So Nissan needs to be sure to provide us with the means, and the education to be able to stop the Leaf in the event of a stuck throttle or motor controller.

How about the brakes? We are only trying to tame 107hp.
 
LEAFer said:
Shouldn't it be accessible to emergency personnel located closer to the "exterior" of a (smashed) car ? (Notice how in some accidents the occupants need to be "cut out" ... how do you get in there and pull the switch ?) Wouldn't a better location be under the hood or trunk -- which, if heavily damaged, is often "popped up" ?
Is this "disconnect" the same as or related to the SRS disable that emergency personnel needs to get to ?

There's also an inertia 'crash switch' inside the battery box that disconnects the pack in the event of a crash.

If the car rolls or otherwise exposes it's underside, it appears that first responders can cut the high voltage cables that exit the front of the battery box.
 
DeaneG said:
adric22 said:
So Nissan needs to be sure to provide us with the means, and the education to be able to stop the Leaf in the event of a stuck throttle or motor controller.

How about the brakes? We are only trying to tame 107hp.


No, 3400 lbs and 200 ft lbs of torque.
 
DeaneG said:
adric22 said:
So Nissan needs to be sure to provide us with the means, and the education to be able to stop the Leaf in the event of a stuck throttle or motor controller.

How about the brakes? We are only trying to tame 107hp.


AC inverters do not get "stuck" unlike DC, when they fail it is "open" not closed. I would not worry about that. Since the car is electric I would guess hitting the brake stops the inverter if under acceleration. I really would not be concerned about this issue unless you had a DC conversion, then you really need to take safety steps.
 
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