I'm sure this has probably been covered before, but I didn't find it anywhere, so I thought I'd create a post regarding a "quick battery disconnect," for those storing their cars, needing to connect and disconnect the battery quickly/easily while working on it, etc.

For $12.95 on Amazon, I bought a "Top Post Battery Master Disconnect Switch" made by GAMA Electronics (https://smile.amazon.com/gp/product/...?ie=UTF8&psc=1). It had great reviews and seems really solidly built, so I'm comfortable bringing it to the forum's attention. In case the link stops working, you can search by name or ASIN: B001N729FS.


GAMA Electronics Top Post Battery Master Disconnect Switch

Due to the negative cable dropping behind the battery, the other wires attached to the negative post mount, the recessed post area of my battery, and the trunk spacing around the battery box, I thought I was going to have a hard time finding a decent disconnect, but I was able to make this one work quickly and easily. Note: Please forgive the yellow/brown stuff on the cable, etc. - many years ago, I bought a gallon of Titebond 2 wood glue at Home Depot, and the top wasn't screwed on all the way, so it spilled ALL over my trunk and battery - total infuriating mess - got most of it up, but a few traces still remain - it scrapes right off, but I didn't care enough to be that meticulous where nobody would ever see.


Before Adding Disconnect: Showing Negative Cable Tucks Behind the Battery


Before Adding Disconnect: Showing Wires Attached to Negative Mount


Disconnect Installed: Cable rerouted, Knob In Place - Power to Car


Disconnect Installed: Knob Removed - No Power to Car

I’m sure other disconnects would work, but I’m really happy with this unit, as well as the price. It only takes a few seconds and zero tools to completely disconnect the battery. My only complaint about the disconnect device is that I wish there was some sort of tether to the knob, as once you unscrew it, it's easy for it to fall/roll somewhere else in the trunk. It only has to be barely unscrewed to disconnect the power, so I could leave it mostly screwed in (or barely screwed in, obviously), but it's not really a chance I want to take.

 

Remember that disconnecting the battery causes the emissions and other monitors to go into a 'not ready' state.

 

As it does with most newer cars. A few short drive cycles usually remedies this. What I find more troubling is the whole remote door locking fiasco which can occur after disconnecting the battery.

I got the disconnect because I'm doing a ton of work to my car and found myself frequently needing to disconnect/reconnect the battery.

 

Leaving the car with the battery disconnected for long periods will most likely destroy the backup battery in the alarm system.
On facelift cars it's best to wait at least 33 mins with the doors shut before disconnecting the battery, in order to lower the risk of corruption problems with the BCM which will prevent the car starting - see https://www.jaginfo.org/threads/how-...attery.113649/

 

That's great info - thanks! I'm not sure if I've been doing it correctly or incorrectly over the years, as I've never really paid attention, but the only issue I've noticed is that I can no longer lock the doors with my remote. I guess if I have any issues when I'm all finished with everything else, I'll deal with it then. Thanks again.

 

I think the door lock problem can sometimes be avoided by making sure all the doors are shut when reconnecting the battery.
Apparently the autologic scan tools have something that fixes it, and I've heard some suggestion that there an "imobilization procedure" in SDD that can fix it too. ( The no-start problem is a different issue, and requires an external programmer to be attached to the internals of the BCM to fix! )