Vehicle: 1982 300TDT 150,000 miles 1985 380SE 130,000 miles 1991 560SEL 81,000 miles (a/k/a the nightmare)
Location: Massachusetts
Posts: 1,657
Battery Kill Switch...
What's the best way to install a battery kill switch in a W126? Should I go for one that isolates the battery as well as the alternator (I think that would be a lot of work, and could be a reliability issue down the road), or can I just go with a negative terminal quick disconnect type?
Teutone: I searched 'battery kill switch' and 'battery switch'... when I type in 'battery' alone, I get too many hits to sift through
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"I don't think it's nice, you laughin'. You see, my mule don't like people laughing. He gets the crazy idea you're laughing at him. Now if you apologize, like I know you're going to, I might convince him that you really didn't mean it."
"I love the smell of diesel in the morning... smells like... like victory"
Rather than a Kill Switch, I velcroed the correct sized wrench for the cable connections to a battery cable. Didn't think I'd need a switch, but having the wrench right there was enough for me.
Why do you want a kill switch? Gonna race the beast??
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Blasphemous Mike
US '87 560SEC with Euro headlights, clear markers, H&Rs, 18x8.5, ATE slotted rotors with semi-metallics, BergWerks FGS, 3.07 Limited Slip.
In progress - FrankenBenz SEC: GM LS6 5.7L engine with custom 4L60E 4-spd overdrive transmission, GM rack and pinion.
There is a very fine line between "hobby" and "mental illness."
Vehicle: 1982 300TDT 150,000 miles 1985 380SE 130,000 miles 1991 560SEL 81,000 miles (a/k/a the nightmare)
Location: Massachusetts
Posts: 1,657
Well, I want one for a few reasons for two of my cars. I've got a W123 with some electrical gremlins, and a W126 with one gremlin... Both have ACC-III problems that I will sort out as soon as the cars are available (long story).
For ease of mind, I wanted to set up a battery kill switch for those around here that will be driving the car, but are not technically adept enough to turn a wrench. I'm hoping that I can just tell them that a battery kill is installed, how it's easy to use, and that it is used under these circumstances: electrical short/fire, storing the car for periods of time away from the garage and charger units I set up.... and lastly, to keep my drunken brother in law from taking the cars out of the garage while the household is asleep and crashing them many miles away from home in the middle of the night... thus leaving me in the lurch when it comes to having enough cars on the road so that I may lay each one up in turn to sort their issues (For this, I'll have to install one on each car... and one on him )...
Anyway, no, I am not looking to race the cars, I've just had two electrical fire scares recently, and want an easy way to kill the battery...
Putting a battery kill switch in a convenient location close to the driver's seat will require running some lengths of awkward 0-gage or 2-gage wire.
There is a convenient access hole in the firewall right next to the battery, so no drilling is involved.
I would prefer to have the switch installed underneath the dash on the driver's side (where one would install an alarm kill switch), but to get heavy wire to that location from the battery will require a bit of finessing as there is limited space behind the heating and ventilation equipment in the center console.
There's a different solution to the drunk brother-in-law: turn him in and let the justice system deal with the problem. You just might be doing your sister a favor. Not that she will ever forgive you, but in the long run she'd be better off without him.
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Regards,
Axel
1990 SEC, Arctic White w/gray interior, M119.960 326 Hp. engine from 1992 500 SL, 722.370 transmission from 500E (reinforced clutches), 2:82 Differential, Euro Headlamps, 1st Gear Start module, One-Touch Window module and Keyless Entry module all from BergWerks, Bilstein HD Shocks on front axle, H&R lowering springs front and rear, AMG 3-piece 17" rims, 8.5" in the front and 10" at the rear.
Yes, you need to have the alternator on the "disconnected" side of the switch. Else, if you will remove the battery from the circuit with the engine running, the alternator will continue to put out voltage. The car will continue to run, and the unfiltered alternator output can easily damage all the electronics in the vehicle.
Of course, if you're mostly interested in having a battery disconnect, not a kill switch, than either side of the battery is fine to put it on without reconfiguring the alternator. You just have to be very sure not to disconnect it while the engine is running.
The cable from the battery to the chassis is the shortest and cheapest of the cables. Not sure if the auto parts stores (e.g., Autozone, Pep Boys) will have a kill switch but Summit Racing has many kinds. For a quick "kill", I'd suggest having a cable made up with the switch to use on the ground side of the battery.
The cable from the positive side generally is a special thing with other wires coming off of it to feed other circuits - an expensive, difficult to replace chunk of the wiring.
Vehicle: 1982 300TDT 150,000 miles 1985 380SE 130,000 miles 1991 560SEL 81,000 miles (a/k/a the nightmare)
Location: Massachusetts
Posts: 1,657
From what I'm reading this should do nicely mounted on the negative terminal... I guess my safety for the alternator would be turning off the engine before disconnecting... I'll have to put a very bright warning sticker on this apparatus, I guess...
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