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Remote battery kill switch

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Mojan Mojan Norouzi
Fremont, CA, USA   USA
What you guys think about placing this relay on battery ground ( next to the battery) and wire small toggle switch to inside of the cabin.
So by turning on/off the toggle switch we can kill the battery. Can be use as emergency switch and anti thief?

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Midgies Dad Avatar
Midgies Dad Ben M
York, ME, USA   USA
This was my solution. One hole in a panel, just above the heater flap to the left of the passenger's knees, so the unit is in the engine compartment next to the battery, and the key is inside the car where I can lean over from the driver's seat and turn it.

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flat350 Avatar
flat350 Steve Alleman
Schaumburg, IL, USA   USA
Why not just use a real disconnect switch

1971 MG Midget MKIII

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ken472 Avatar
ken472 Ken Petersen
Luverne, MN, USA   USA
The original owner of my car rewired it with a switch and relay the way you propose. It has worked fine for one 20 years. It needs to be a continuos relay not a starter relay.

Mojan Mojan Norouzi
Fremont, CA, USA   USA
I just did not want to make a whole... but you guys convinced me smiling smiley
For the kill switch that you attached, I do see a price range from $7-$20 which one to buy ?

Midgies Dad Avatar
Midgies Dad Ben M
York, ME, USA   USA
You can't tell if a more expensive one is better than a cheaper one -- retailer A may sell many more for less cash retailer B sells fewer of them but gets more for each one, and they probably all came from the same manufacturer. I got mine off epay. And $20 isn't much, so splurge if you feel like it.

Edited 1 time(s). Last edit at 2018-01-03 03:32 PM by Midgies Dad.

mickri Chuck Losness
Squaw Valley, CA, USA   USA
I have used those types of battery switches on my boats for years and plan to have switches on both the positive and negative battery cables on my midget. The only thing to be careful of that I know of is that the switch has to be rated for more amps than the battery. The back of the switch should be hard to get to. Otherwise a thief could just put a jumper across the terminals. My plan is to mount the switches in such a way so that you have to remove the battery to get to the terminals.

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Midgies Dad Avatar
Midgies Dad Ben M
York, ME, USA   USA
If the thief can get to the battery, he can just put jumpers to the coil and the starter, and drive the car away.

Jan Kruber Avatar
Ballerup, Copenhagen, Denmark   DNK
Talking "kill" switch, can anyone please give me some reasons for fitting such a device? When I bought my Midget it was equipped with a switch like the one in #2 in the engine bay.
Being an old experienced electrician, I'm fully aware what impact a battery can have if shorted, with allmost non internal resistance it just gives full power until wires or whatever melts down or the battry explodes.
But the electrical circuits should be protected by fuses - exept for the big wire going to the starter, off course.
So is it because of this circuit you guys fit the switch?
I didn't want the switch, but since it's very common with those switches, I thoose to fit a quisk release cable shoe on the negative battery pole..........just in case.
Is it a device fitted by owner's, only because they can?


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djclinton Avatar
djclinton Dennis Clinton
Mesquite, NV, USA   USA
1964 Ford Ranchero "Red Rocket"
1966 Other Custom "Green Machine"
1979 MG Midget 1500 "Bridgette(brown Midget)"
Because my 1500 sits a while between use, I installed an electric fuel pump(so I can prime the carbs first). I added a 'kill' switch in the glove box for the pump(it has a relay too). I also have a disconnect on the negative battery terminal-used when I work on the car, or when I'm out of town for an extended period of time.

AN5L8016 Avatar
AN5L8016 Mark Haynes
Nederland, CO, USA   USA
There are various reasons for installing a kill switch, some are more realistic than others.
When road racing in the US, It's sometimes (depending on the type of racing) mandated that you have an external kill switch so that corner workers can cut the electricity off from outside the car should you wind up on your top, to protect from fires and short circuits. The removable flag allows the corner workers to ensure that there is no power present.
Some people install them to try to protect their battery from draining during periods of non-use.
some people install them as an anti-theft device, thus the switch in the driver's footwell or under the bonnet.
There are also switches that are specifically for alternator equipped cars that contain a diode to cut all power- If you cut the power to an alternator car while its running, it can continue to run off of the alternator alone, and not have it kill the engine.

'58 Bugeye
'05 Mini Cooper S

Jan Kruber Avatar
Ballerup, Copenhagen, Denmark   DNK
I toyally agree, I'm aware that here in Denmark too the racers has to have a kill switch accessible from outside the engine bay. I'm allso aware, that newer cars / motorcycles with ECU and all sorts of electronic equipment can slowly be discharged when stored for longer periods, with motorcycles that's my experience at least.
Which means that I will continue the ownership of my totally analoque Midget without a kill switch, since it isn't equipped with any of the before mentioned modern equipment's
thumbs up


BlueMax1 Avatar
BlueMax1 A G
?, ?, USA   USA
I use a AGM Braille glass mat battery. In order to keep the battery at its peak condition I use a optimate battery charger. I keep the main kill switch open while car is park and charging. I mounted it to the fire wall beside the relay box.

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Rocky point, NY, USA   USA
In reply to # 3655831 by flat350 Why not just use a real disconnect switch

I agree I have one in my 74 midget and remove the key when I’m not with the car. Don’t remember last time I took the key out of the ignition. Works great I bought 2 just Incase I lost the key been 5 years and still works great

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