Turn your battery terminal into a quick disconnect

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GeekEV

Well-known member
Joined
Jan 18, 2011
Messages
1,825
Location
NorCal, USA
While looking into adding a quick battery disconnect (to facilitate a reset should any glitches arise, as discussed in other threads), I found one sort-of already in place. Just use a 13mm socket to remove the existing nut and replace it with a 8mm wing nut from home depot and you're good to go! If you're careful to support the right hand side of the assembly while you make the swap you won't even disconnect while doing it...

5590678757_66045fe947_z.jpg
 
What happens when your wingnut vibrates loose, because you couldn't get it tight enough???
M
 
scmike said:
What happens when your wingnut vibrates loose, because you couldn't get it tight enough???
M

It won't. I use those cheap quick disconnects on my classic Minis, which are arguably the most rattly cars in existence, and they don't come loose:

BatteryDisconnectSwitch


Garygid put a lock-washer under his wingnut, just to be on the safe side, but from my experience it just ain't going to happen.
 
mwalsh said:
scmike said:
What happens when your wingnut vibrates loose, because you couldn't get it tight enough???
M

It won't. I use those cheap quick disconnects on my classic Minis, which are arguably the most rattly cars in existence, and they don't come loose:

BatteryDisconnectSwitch


Garygid put a lock-washer under his wingnut, just to be on the safe side, but from my experience it just ain't going to happen.

Hi Mike, it looks a little bulky. Will this contraption clear and fit under the Leaf bonnet without knocking around??

Thx.
 
This is all getting ridiculous! If you feel you need to make this modification to your car, then call your dealer to schedule a service appointment for whatever is going on. I know some are concerned about software issues (which is where this whole disconnect thing began), but really the car is under warranty and covered with roadside assistance. Disconnecting all of the power, thus clearing some or all of the error codes, is not going to help solve the root problem you maybe concerned about or experiencing.
 
mxp said:
Hi Mike, it looks a little bulky. Will this contraption clear and fit under the Leaf bonnet without knocking around??

Thx.

I'm not sure, I've not sat inside the LEAF engine compartment with the hood closed to see how much room remains between the hood and the top of the battery. :lol:

In any case, I'd not necessarily advocate using one of these over simply replacing the existing nut. However, for the sake of a more elegant solution, one might want to consider a steel knob like this one from McMaster Carr instead of a wing-nut:

http://www.mcmaster.com/#knobs/=btfcxz
 
GeekEV said:
While looking into adding a quick battery disconnect (to facilitate a reset should any glitches arise, as discussed in other threads), I found one sort-of already in place. Just use a 13mm socket to remove the existing nut and replace it with a 8mm wing nut from home depot and you're good to go! If you're careful to support the right hand side of the assembly while you make the swap you won't even disconnect while doing it...

5590678757_66045fe947_z.jpg


why do this? as in what is the utility of this?
why have a quick battery disconnect.
 
buddf said:
Why not just just keep a socket and driver handy in the car?
The answer to why, in this case, is quite simply because you can. Yes, you can carry a wrench in the car, but where's the fun in that? :lol:
 
Don't use a wing nut past the time you get the issue repaired or even a disconnect as the car was not designed for this and you are likely going to have a bigger problem down the road.
 
I'm thinking of doing something like this, in response to a recent ABS failure that was likely triggered by a low battery voltage condition, which I would have been able to clear up if I had the ability to disconnect the 12V battery. I've added a 10mm wrench to the center console since that happened, but being able to disconnect without tools is preferable.

My initial thought was to do this on the negative terminal. It's slightly more accessible, and the wing nut won't interfere with the red insulator that goes over the positive terminal. But I've read the warnings against connecting directly to the negative terminal (and thus bypassing a current sensor). The disconnect point I have in mind would be after that current sensor.

Does anyone see a problem with leaving the current sensor attached to the battery negative terminal while temporarily removing the connection from there to the chassis ground? This would just be for 'emergency' purposes, typically to be able to clear stubborn DTCs (falsely raised due to a flaky 12V battery), that are preventing normal vehicle operation.
 
The warning not to connect to the negative terminal is related to the possible sparking and ignition of hydrogen outgassed from an overcharged battery, which is not likely to happen with the poor aux charging algorithm performance seen in the laef.

The coulomb-counting current sensor is useless on these cars and may actually be part of the problem with keeping the aux fully charged.

The 10mm wrench is a better solution than some flimsy junction that might accidentally work loose during operation--losing the return path would cause momumental ECU damage.
 
Bobkart,

There is no reason not to disconnect the negative terminal--it is safer because a slip of the wrench (bumping the body or other metal) will not cause a spark since negative is already chassis ground. You will not hurt the current sensor and there is no need to unplug the sensor wiring connector. I have disconnected the battery by removing the negative battery cable from the current sensor numerous times on the 2011 and 2015 (have not needed to yet on 2019). I thought about replacing the nut with a wing nut or plastic knob with metal nut insert, but decided just to keep the correct size wrench in the glove box or console (so it is accessible without opening the hatch in case system is dead).
 
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