Disconnect switch for slow battery drain?
 

Any wisdom on a battery disconnect for a slow battery drain that has defied troubleshooting.


Looking at this product, which disconnects when voltage begins to drop.




Then reconnects when key inserted.


I'm having a persistent slow drain (3-5 days). No issues for overnight or regular use.


$80 seems cheaper, at least as an interim solution, than electrical troubleshooting.

I have one of these on my trail truck.
It was even cheaper at Menards, maybe $3? Install on the negative terminal. Turn the screw clockwise to connect, counter-clockwise to disconnect. Super easy and cheap.
I actually have that same switch installed on my Dodge Van which has an issue with the BCM. The resolution is to disconnect the battery for 5 minutes. Much easier with that little switch.

What I liked about the more expensive, automatic option was that I didn't need to get under the hood or remember to flip a switch.


It automatically senses if battery is draining below where it will still start. But otherwise it stays connected.


One other ignorant question: does disconnecting the battery reset the ECU? How big a deal is that?

You can use it to protect a no start, but you are eventually going to have to charge battery on occasion. when it turns off at safe voltage, you have to drive it long enough to bring voltage back to specs and start all over again. If 9.6V is the minimum an engine will start does the electric shut own before this, as you cannot charge battery enough to stop and have electric shut down then not have the least voltage to start again. Back to square one. A manual disconnect will turn off while at 12V and turn back on at 12V.

It would probably reset the radio so keep the code handy. Interesting that the amazon listing says they may be new or used.

I use the manual switch on most of my seldom run vehicles, although if left long enough batteries can self drain, and sometimes these Chinese manual switches cause their own problems with bad contact.