JX kill switch installation - battery to body earth problem

[jj_sivu]

I´ve had my 1.6 TD 1989 Caravelle Syncro stolen once and broken into once during the past year that I´ve owned it now. I´ve installed a burglar alarm and some motion detector activated lights, and thought about putting in a main circuit breaker as well.

The problem is that the battery to earth location is a bit tricky: once undone, I couldn´t get the long bolt where the negative cable is connected to out, because of a screw protruding itself off the back of the alternator. The screw is situated directly on top of the bolt where the negative cable is screwed into.

The idea would be to put in a new earth cable to the body earth location and install the kill switch between that new cable and the old negative cable connecting to the battery.

So I thought that the easiest thing to do would probably be to cut off the screw protruding from the back end of the alternator. Would there be any negative effects on doing this? I tried to to unscrew it, but it was in such a tricky place that I couldn´t do it even with proper tools. And I wouldn´t like to take apart the whole alternator either.

Also, by using this type of kill switch, is there a danger that the extra electronical devices that have been hooked up to the positive side of the battery will be damaged when the negative side is cut off and you try to start the car?

[cassandra]

Hi, probably just me but don't quite understand. Do you want to isolate the main battery earth lead or the engine earth lead?

[Oldiebut goodie]

Not just you - I have read it several times and I cannot work it out either!

[marlinowner]

http://m.ebay.co.uk/itm/Heavy-Duty-Batt ... nav=SEARCH" onclick="window.open(this.href);return false;

Just fit one of these on the battery -ve terminal.
Nothing will happen if you try to start the engine (or turn on lights etc) with the battery earth disconnected.

[cassandra]

An excellent idea but you would need to run separate earth cables to the battery for the alarm and security lights?

[jj_sivu]

The aim is to isolate the main battery earth lead. Good thing to know that the kill switch does not propose a threat to the additional electronics wired to the plus lead. I'd still have to saw off the excess bit of the screw that is blocking the access to the bolt where the battery earth lead is attached to. (screw coming off the backside of the alternator) I guess that's fine.

The lights and alarm are not connected to the car battery, so that's no problem.

The proposed isolator seems like a good and simple solution, but I guess you would have to open up the engine cover every time to access it. I'm trying to place the kill switch in a way where I could operate it through the licence plate opening.

[Jeff J]

Isn't your battery under the drivers seat?

[Oldiebut goodie]

No - JX.

[marlinowner]

I would just add that if you fit a fused connection in parallel with the kill switch then radios, alarms etc will still be powered, but fuse will blow if the starter is energised.

[nicq]

Not a lot of help if he wants to keep burglar alarm as the fuse will blow to the alarm if they switch it on.

[marlinowner]

Well yes, probably shouldn't have said alarm, especially as OP says above that alarm is seperate. Would work for alarm with backup battery though...

[Jeff J]

Not a lot of help if he wants to keep burglar alarm as the fuse will blow to the alarm if they switch it on.

I might be wrong but I would have thought the load would have been drawn through the radio/alarm etc. & therefore damage them before blowing the fuse.

[marlinowner]

The starter motor is in parallel with the radio etc, no load through them. And if you did wire it up in series, when the starter was turned on the radio would come on and the starter would do nothing, electrically its just a length of wire wound into a coil.

[jj_sivu]

Like I said before the alarm is not connected in anyway to the car battery.

This is how I am planning to install the kill switch:

https://www.youtube.com/watch?v=PAeD0xi ... 0&index=34" onclick="window.open(this.href);return false;

So is there a consensus whether trying to start the car with the earth cable disconnected would damage the radio etc.?

[marlinowner]

It won't.