battery cut-off switch - instructions?

[antichrist]

Originally Posted by Divied245

just because you interrupt the ground side of the battery doesn't mean there isn't power flowing anymore.

Again, electricity can only flow if there is a complete circuit from the positive to negative posts of the battery. If the negative post is not connected to anything, current can not flow.

[lwbblue]

hey tom, you are right which I missed last week. what was I thinking!! too early in the day.

[hermanpj]

fascinating... why does the ECU need power when the truck is sitting dormant for a month?

[stolenheron]

Originally Posted by hermanpj

fascinating... why does the ECU need power when the truck is sitting dormant for a month?

there is are still running processes going while the truck is off. Not sure how many a rover can have, or does have, if any at all, but that is the idea behind it.

for example. the 2002 Porsche 911 my family used to own can have over 200 running processes going at any given moment while the car was off, which is why a trickle charger is recommended for any dormancy applications.

as far as the cut-off switch, they are supposed to be used for emergencies.

and my boats have always had the power cut-off switches on the positive side.

[hermanpj]

wow... i just find it hard to believe th 1991 rover with its Lucas 14CUX EFI computer has got that much going on when the truck is shut off, or moreover that it makes a difference to how the truck is going to run if i shut the ECU off completely for a month at a time by disconnecting the battery. this aint exactly a 911.

i think the type of cut-off you are thinking about for emergencies is more akin to racing applications. the one i bought is advertised specifically for preventing parasitic drain. just the dang thing came without any instructions.

as to eliminating the source of the problem, yes this is good thinking. problem is that in the only electrical change in the last 2 years has been the addition of a new stereo head unit and amplifier. both are wired exaclty correctly. the stereo head unit does draw power to retain settings, but not any more than the previous head unit. The amplifier (which would be my biggest concern of the two) is definitely not drawing any power when the ignition is off. it is remotely shut off by the head unit and that function is working properly.

so in terms of finding the problem, I am going to see if maybe the alternator is causing the problem, but barring that, finding anything else draining the battery will mean a front to back witch hunt. i've already had as much fun with the wiring harness as i'd like so i'll pass. if it is either the head unit or the ECU draining the battery, i'm fine with the approach of disconnecting the battery via switch.

[rqsall]

I used to park our truck in the lockup box for weeks with the ground connection to the battery removed. Never had a problem related to ECU. In fact, it was disconnected for months while I slowly rebuilt the engine over the course of several weekends. Only thing that bugged me was that the alarm (aftermarket) always goes off when you reconnect the battery, so I reconnected it with the ground lead in one hand, remote in the other to stop the siren as soon as I connected it again