Remote isolator.

[Carolyn]

This is my second stab at this project.  The first attemp worked for a while but th '100 amp' relay died.  It probably died because I was switching the entire negative side of the battery and, therefore, putting the cranking power through it.
Another drawback was the current greedy coil in that big relay, meaning it would pull the battery down in a couple of days. That's on top of my already greedy aftermarket security system (MR S doesn't have a factory unit.)
So second try:

First I needed to find a proper 100 amp 'Latching' relay.  Latching devices don't require constant current.  When operated they stay switched in either open or closed state.  It took a lot of googling, but I did find one.

Then I needed a remote that put out two signals - 'on' and 'off'.  I found a winch control that does 'in' and 'out' - same difference!.

Next, I put the relay on the positive side, but only on the car systems circuit and not switching the main cranking power.  It's handy that the two systems have their own connection on the battery terminal.

Total cost for parts £35. 

[Petrus]

Is this an anti-theft device?

[Carolyn]

It's an anti-flat-battery device.

[Petrus]

Ok, get it.
I had a small solar panel for that on other cars with a rather high key-off current.
With the UK after market alarm fitted, you definitely want something like that.

[1979scotte]

Sign me up for one.
It's a great anti theft device too imho.

[Carolyn]

Sign me up for one.
It's a great anti theft device too imho.

If you buy the bits, we can put it in when you're here.

Relay: https://www.ev-power.eu/_d3125.html?gclid=Cj0KCQjwoebsBRCHARIsAC3JP0Ic6gorBBz6XERXnmBsVnvXP2CniXA74_mqs_9WUCfX8R9Qign2oxsaAuf2EALw_wcB#tab2

Remote:  https://www.ebay.co.uk/itm/12V-50ft-Winch-Wireless-Remote-Control-Switch-Handset-For-Jeep-ATV-SUV-UTV-Set/223566277029?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m2749.l2649