Battery cut off - any tips?

So I bought myself a nice big 40 amp relay and a switch. I'd like to wire them into a battery cut off to try and deter any would-be thieves.

I was going to separate the battery cable between the positive terminal and the starter somewhere, would this be the right point to break the circuit?

Need a way bigger relay if you are going to break in to the battery / starter cable (500+ amps). There is already a 'starter relay' that the ignition switch uses to send power to the starter solenoid connector. A better method would be to break into the existing starter relay coil circuit and install a hidden switch. With this switch 'open' the starter wont get a signal if the key is turned to the start position.

Well good thing I asked isn't it!!

I'll have a look at my wiring diagram.

It's just more to go wrong, plus disconnecting the battery could cause more problems with alarms and imbolisers. As they think the car is being tampered with as the battery is not there.

Plus the radio looses its stations.

Mcclegend said:

Plus the radio looses its stations.

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What - you can actually hear the radio !!
Best get me a quieter 90 then

Cut off the fuel solenoid on the pump with a hidden switch, it won't go anywhere without fuel.

Fuel solenoid seems to be the best option I think. Going to have a play this weekend. I bought a key switch from Maplins, so even if they find the switch they won't be able to turn it

I don't have an alarm, immobiliser or radio. All I have is lights, and even they don't work all that well!

DON'T cut off the battery, that's just asking for problems.

DEFO cut off the fuel pump instead.

Leave one of these asleep underneath your Defender. I don't even bother to remove the keys or close the windows in the summer. Never had a problem in five years.

im also interested in this. has any one else put a hidden switch to the fuel pump ?

Hey gang,

I fitted this today, and I'm pretty pleased with it. I've fitted the relay in the engine bay and used old mid-matched wiring to try and stop it standing out.

I've wired it up so its live as standard and kills the feed when the relay is live. Hid the switch somewhere in the cabin, so it's easy to get to.

Quite a simple job once I worked out what the relay did!

Hi Merryck,

Did you use the 90 amp relay ? if not what size did you use?

Cheers

I used a 40 amp relay.

Well I can safely say the cut off works, I spent more time this morning than I'm willing to admit trying to start it before I realised why it wouldn't work!

Why not a battery cut off? I have a battery isolator I use when the vehicle is parked up

Merryck said:

Well I can safely say the cut off works, I spent more time this morning than I'm willing to admit trying to start it before I realised why it wouldn't work!

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I regularly lose my keys in my pocket.
This behaviour is what links Land Rover owners and squirrels

I didn't cut off the battery because I bought the switch and relay, and they wouldn't handle that kind of power. The reason I wanted the switch in particular is because it's only operable with the right key, so even if they spot it it just looks like it locks the panel in place. Of course they could just rip the panel out and connect the wires, but hopefully that won't occur to them.

Funny you should mention the squirrel connection, I actually stored my spare key in the tree in the garden. It should be safe there for the winter.

So you have a current running through the relay when ignition is turned off and it's not running???

When I've got the pump deactivated there is a current going through the relay, yes.

Sounds a back to front way of doing it to me, personally I'd wire it up so the pump circuit is connected when the
relay is energised and broken when not, to prevent battery drain etc.