47-59 Battery disconnect

[skip99]

So, i bought a battery disconnect, now deciding whether to use it or not, opinions? I have a powermaster mini starter, anyone have issues running all the power through a switch? Thought about running cable straight to starter and then everything else through a main switch, such as power for lights, and such...really just want it for the ease of killing power as battery is mounted under cab, in case of emergency or maintenance, i guess the biggest question was will the switch cause any issues?

[notsolo]

Thinking the same thing, but maybe on the neg cable. I also added a parasitic drain when I up graded to serpentine belt set up, it seems the 12 volt wire on the alt is the culprit. cut the power here it won't start. I haven't figured where, or how to run a kill switch.

[mongocanfly]

All I've seen are on the neg cable..

[skip99]

Ah, didnt think of neg cable, that would be easier, battery through switch back to frame....

[mongocanfly]

My C30 came from a local fire dept...they had one on it on the neg cable..the switch was under the seat..
Good theft deterrent also
Down side is if you have a digital radio is losing the presets...

[notsolo]

Is yours like an old rotary switch, 1 click on 1 click off? Engine negitive wire to switch then battery?

[skip99]

Its a pollak spst,

[notsolo]

Thanks, I had to look that up...I have a cheap version. That looks easier to mount.

[mongocanfly]

Mine is a pollack... had one on my race car also back in the day

[mick53]

As long as your switch is rated large enough it will be fine. Switching the negative is much safer.

[skip99]

Ive seen that if i wanted to kill the motor while it was running, a 2 pole switch wont work , so i assume i would need a 4 pole, does it simply cut the power to hei? Ive seen the alt. Mentioned, but i will run a single wire alt, so i dont think that will work

[72Mountaineer]

I put a heavy duty on/off switch (like the one used on drag cars) under the passenger side of the seat, everything except the starter and 1 wire alternator goes through it.

[mr48chev]

Originally Posted by skip99

Ah, didnt think of neg cable, that would be easier, battery through switch back to frame....

Cutting the ground off shuts off everything in the electrical system. The only thing you need to make sure of is that the alternator doesn't feed back and keep power to the engine. That will be figured out the first time you flip the kill switch with the engine running. Still you aren't going to have it mounted in the rear panel of the truck so a drag strip safety crew can shut things off.

I've got two batteries on my boat with a cut off switch that is also a battery switch It has off or can be switched to run off one or the other battery so you can run the boat off the second battery without draining the one for the engine.

[mick53]

I will need to run 2 batteries so I can run the A/C with the engine off.

[bosco]

Agree with you guys. I installed mine up under the dash on the negative side. Initially to add a deterrent if I have to park overnight at a show.

[dsraven]

be careful what you are doing with regards to running the engine and cutting the power with the engine running. that is basically how they used to get 110 volts from an alternator so they could run a drill or some other tool, back in the day. you could burn up some electronic stuff especially if the dizzy still gets juice to keep running. anyway, think about it and research your particular system. check with a starter/alternator rebuilder, they have switches like you need quite often and can possibly give some insight in to how to wire it. it's a good idea to switch the ground rather than the power just because that is the ground cable so any sheet metal or other steel parts nearby would usually also be a ground. if there is a problem with a cable or a switch and a cable burns off or some other malfunction occurs any loose cables that touch surrounding parts will not cause a spark or short to ground. also, generally, there is less corrosion build up on the negative terminals due to how electrons flow through the system and the negative terminal will usually have less wires qnd connections going to the terminal. do a bit of research on how much total draw you would have at max intermittently and then the usual normal draw with lights, heater, stereo etc, usually that would be starter draw as a max, and ensure the disconnect switch is rated for that much amperage at minimum. a stop at a farm or heavy equipment parts supplier may set you up. possibly something like this.
https://www.amazon.com/Fastronix-Cur...M2G5SM86AMFSCW

[skip99]

Follow up.....so i put the switch on the ground side, if i need a ground maintained for the radio, or gauge clock, what do you suggest? It seems the only thing possible is to run a small ground wire with a 1/4 anp fuse, that way if anyone tried to start it it would just blow the small ground fuse ...or is the some other way? I assume once i run a ground to radio or gauges, the whole thing is grounded because they are not isolated

Or , since i use electronics, maybe I should just use the switch on the battery to starter wire?

[mick53]

I had a friend install a small rechargeable battery pack to run the electronics when the power was off.