Parasitic Drain/Negative battery disconnect

[Logan Robb]

If it's not one thing, it's another. My electrical gremlins continue. 

I decided the weather was going to be nice this week and it so happens that it is my "in-office" week. So I figured I'd live it up and make my commute to and from work a little more enjoyable and take the 64 Fleetwood. Monday was a success and the Tuesday morning commute was also a success. However, when I went to leave the office, the car was stone dead. I mean, no nothing. Completely dead. Now, it is possible I left something on that caused it to die a little faster than normal. But I am unsure. 

Notice how I said, "die a little faster than normal"? Yes, this has been an ongoing issue of parasitic drain from somewhere, but I have no idea where. Normally, if I do not disconnect the battery overnight, the battery will be dead. I have found it takes about 24 hrs to die completely. Well, today it was dead, dead, dead in almost exactly 8 hrs. 

So-Where to begin? I know I should fix the issue PROPERLY and find the source of the drain, but that is a little more involved than I want to take on right now. I think I have a better idea. 

I like the idea of keeping the battery disconnected when not in use. My clock doesn't work anyway, and that is the only thing that I would eventually have to sort out should I proceed with this idea. I can't seem to find anything like this on the internet so I am coming back to you all to gain some knowledge. 

OK-here is the idea. Presently, I have a manual negative terminal disconnect on the car. This requires me to pop the hood and connect and disconnect the switch. This is fine, but a little fiddly to do every time I use the car. This works very well at keeping the battery charged and preventing drain. I am thinking about a relay-controlled solenoid that connects and disconnects the negative battery terminal. The switch would be located in the cabin somewhere, probably the glove box, and then the relay to control the solenoid would be located somewhere discrete in the engine bay. Doing it this way means I do not have to constantly be under the hood of the car. To my knowledge, doing it like this means the ONLY thing powered up while the solenoid is not connected would be the switch that connects to the battery power. 

A few questions rise with this. Are there any electrical dangers to doing it like this? Do they make such a solenoid that would be able to support this idea? Such as a "constant use" solenoid? Im not looking for a vehicle fire, so please chime in if this is something you have experience in. 

You may ask yourself, why a relay-controlled disconnect? Well, most of the conventional positive terminal battery disconnects require heavy gauge wire to be run and then the switches are big and bulky. I'm really not interested in that much modification and running it with a relay is smaller wires and less visible than the positive cables. 

Let me know what you think! 

Thank you, 

Logan

[Logan Robb]

I have no question the battery is good. I just replaced it last September. Charging system is also good to my knowledge. 

I do keep it on a battery maintainer when not in use for long periods and also disconnect the negative terminal nightly. 

Logan

[3ft7bqmb7dryo]

I put in a system that you described into a clients car. It had a hand held remote that turned the battery on/off. 

Just find one that is powered on, not powered off, as it drains the battery if left on for an extended period of time. 

I do suggest troubleshooting the drain, as it may worsen into a fire.  There are multiple areas to check, as there are multiple areas that have constant power.  Disconnect the power seat first to see if that is the drain. Seen pics of the seat relay sticking causing a seat fire. The car usually is a total loss. 

[Logan Robb]

I certainly don’t want to burn the car down and I do believe it merits checking out. Even with the issue addressed, I still like the idea of being able to disconnect the battery if leaving the car for more than a few moments. 

I think a constant use solenoid should be fine and then everything else is just parts store stuff. 

[Patrick Westphal]

OK so here are some possibilities for your battery drain problem.  First of all I would just keep the manual system you have and work on finding the actual problem.  There is nothing on our cars that should be a drain on the battery from a production standpoint.  Now if your vehicle has updated modern equipment on it such as a modern stereo or other added accessories then that statement is maybe not completely true.  From a production standpoint the battery directly powers three fuses.  The horn fuse, body feed fuse, and tail light fuse.  It is possible that your brake switch is out of adjustment and the brake lights come on after you park the car.  I had this issue and in my case the brake lights would illuminate after more than 10 minutes of ignition off time.  The problem was that the brake pedal would move just a little bit after some time because of gravity on the pedal itself.  Other possibilities are the generator or regulator having an internal resistance path because the part is going bad.  It is also possible that a buildup of grease/grime on the outside of these devices could provide an electrical path to ground that will drain the battery.  Cleaning everywhere the positive battery cable connects is a good idea (including the start and start solenoid under the car).  Also you could pull each of those 3 fuses one at a time and see if the battery drain goes away.  This of course requires a method to measure the current coming from the battery when the car is turned off.  I use an ammeter of the negative battery cable side.  BTW, I can help you with that non operating clock.  See the latest newsletter.  

[Logan Robb]

To my knowledge, the only aftermarket electrical item is an electric fuel pump. 

[Jason Edge]

If you disconnect the positive battery cable and have a multi-tester that reads amps you can get an amperage reading of the draw by touching the battery cable end with one contact and the battery + terminal with the other. You could then go down the fuse box as you are cleaning the contacts and get readings.  The only thing that should draw any current on these cars when it is turned off would be the clock and and that would be very small.

I would double check the obvious items that could accidentally pull a good amount of current if they were left on. I would make sure the mercury switch light in the trunk is turning off when the deck lid is lowered; make sure the glove box light is going out when it is shut, Make sure the back of seat override switch for courtesy lights is off, if you have any lighter Plug in Adaptors such as USB chargers, you will want to see if they have current drawing items plugged in. The little LED indicator lights pull almost zero current. 

[Jason Edge]

 It would be interesting to know what your car amperage draw is when everything is turned off. I did a quick test of mine and it is only pulling 10.4 mA (milliamps). I am only running a quartz converted clock which seems to pull a very constant current vs the stock mechanical clock that I believe has an intermittent draw every few seconds when that spring pulled the contacts together and closes the circuit drawing current.  That should be neither here nor there for your bigger issue. 

UPDATED 4/20/2023: You may also consider that you have a bad battery. They do sometime go bad in a short period.  NOTE: I have deleted peripheral discussions off topic.

[Logan Robb]

I intend to address this concern this weekend. I’ll keep all updated. I suppose you could be right with the bad battery. Having not been thru that many batteries in my time, I suppose I could be a little naive. 

I will say, I had a Delco battery in my 08 Cadillac that lasted nearly 7 years. I JUST replaced it in January with another. Granted, a 2008 CTS and a 64 60S are two very different birds. 

[Logan Robb]

Certainly a good suggestion. Perhaps I’ll get to that after work tonight 

Logan

[Logan Robb]

Just jumping back into this thread to update all. I did install the system I was talking about. 

I did a small write up here: Installation of the Painless Performance Battery Disconnect - 63/64...

I am uploading a few photos in a moment. Quiet an easy install and not at all hard and the functionality it adds is priceless in my opinion. 

Logan