battery disconnect switch

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RangerRick

RangerRick

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I notice there a many different amp rating switches out there...........some 20 amp continous and others 180 amp. I have one on my vehicle but dont know which size I have. If it is a 20 amp, would that cause any problems? My alternator charges at 40 or 60 amps.... As a separate note I have read where some switches can go bad from vibration with age and create a high speed flutter? anyone hear of this?.......curious
 
It's not you alt I would worry about it's the starter, how much current does it pull.
Doh way more than 20!
 
I ran the 180-200 switch on my camaro, along with a 200 amp relay in the back. I had a 120 amp 1 wire alt. If the battery goes into thermal runaway, that alt will run full tilt and burn up everything in its path.
 
DesertRat said:
Put your battery disconnect in the main ground lead right off the battery and a medium current rating will be plenty.
Click to expand...

Just what "is" "medium current?"

OP..........if you ever decide to show up at a dragstrip, there are certain stipulations......for one the disconnect must be in the hot lead. You can download NHRA rulbooks if you do a bit of a web search
 
Trunk mounted battery?
How is the switch you now have wired in?
Switch amp rating needed will depend on what runs through it...
and that can vary a lot...
 
Question on this subject, My 69 Dart 'Vert has a trunk mounted battery. No shut off switch. First, is this bad, no switch, why if it is. Second, Where have others placed/mounted said switch? Street cat. No roll bar, so no Strip. They wont let it run,it "looks" too fast! :BangHead::lol:
 
Nothing to do with looks.
By rule A trunk mounted battery REQUIRES a cut off switch to run at the track.

You should use a cut off switch and relays.
The cable running forward to the starter should only be hot when cranking.
 
Mopar Tim said:
Question on this subject, My 69 Dart 'Vert has a trunk mounted battery. No shut off switch. First, is this bad, no switch, why if it is. Second, Where have others placed/mounted said switch? Street cat. No roll bar, so no Strip. They wont let it run,it "looks" too fast! :BangHead::lol:
Click to expand...

If it never sees the strip, then you don't need to have a cut off installed. You won't pass tech without one though with a trunk mounted battery if I remember correctly.

I installed one on mine when I did the battery relocation just for convenience, I was doing that much wiring already so having a cut-off seemed handy. Extra theft protection, good for storing the car, and easier to disconnect the battery for any kind of electrical work. Plus I can get it to pass tech with a few additions if I so choose (mostly an external push/pull on the switch). Mine is done with a continuous duty relay and a 300 amp switch

Relay
Moroso Alternator Shutdown Relay Kits 74107
4-pole switch
Moroso Super Duty Battery Disconnect Switches 74102

batt-cuttoff.jpg
 
I don't race my cars so the only reason I use a battery disconnect is winter or long term storage.
Also I like the potential fire protection I get with it disconnected. I use a NAPA manual generic battery disconnect
and put in the ground side of the circuit. They have never let me down. Understandably if you are going to the
track you are mandated by their rulebook how to do it. I guess it depends on your needs but for a street only car
the way I do it has worked well for me. You can see the install in the top right side of the attached photo above
the battery tray.

HoseClamps1.JPG
 
image.jpeg
Not sure of your reason for a disconnect but for a daily or occasional driver this is what I use.
Simple, cheap and effective.
Yote
 
Mopar Tim said:
Where have others placed/mounted said switch? Street cat. No roll bar, so no Strip. They wont let it run,it "looks" too fast!
Click to expand...

there is a member here (cant remember who) who has a custom license plate that reads "on off"
the cut off switch is right in the middle
 
You don't use fusable links and you don't wire a switch on a ground circuit. Especially in a race car setup where you want to kill power to all circuits.
 
Not sure specifically your disagreement, DesertRat. You don't get true fire protection with a negative/ground interupt. You still have a hot circuits. Since you don't race, maybe you haven't looked at the guidelines/requirements for kill switches.
 
Mopar Tim said:
Question on this subject, My 69 Dart 'Vert has a trunk mounted battery. No shut off switch. First, is this bad, no switch, why if it is. Second, Where have others placed/mounted said switch? Street cat. No roll bar, so no Strip. They wont let it run,it "looks" too fast! :BangHead::lol:
Click to expand...

Just because you have a trunk mounted battery doesn't necessitate a kill switch. Many newer cars are using trunk mounted batteries. If you do decide a kill switch is warranted, and you are racing, then consult the sanctioning body. Some road racing orgs require a centrally mounted dash switch, accessible from either side and the driver. Others require an exterior mounted switch. Whatever you choose, just follow the mfr install directions.
 
General Disarray said:
Not sure specifically your disagreement, DesertRat. You don't get true fire protection with a negative/ground interupt. You still have a hot circuits. Since you don't race, maybe you haven't looked at the guidelines/requirements for kill switches.
Click to expand...


Nonsense. If not for NHRA a ground interrupt is just fine. Assuming the battery is in back, and switch at the rear, you only have maybe 2-3 ft of cable that could possibly short and ground the "off" circuit.

When I work on my car THE GROUND IS WHAT I REMOVE
 
67Dart273 said:
Nonsense. If not for NHRA a ground interrupt is just fine. Assuming the battery is in back, and switch at the rear, you only have maybe 2-3 ft of cable that could possibly short and ground the "off" circuit.

When I work on my car THE GROUND IS WHAT I REMOVE
Click to expand...
Two different scenarios. Working on car, remove ground. Kill switch designed to cut all power to everything. For true fire protection switch needs to be in the positive cable. If all you are looking for is a way to more easily work on the car, then put one on the neg.
 
General Disarray said:
Two different scenarios. Working on car, remove ground. Kill switch designed to cut all power to everything. For true fire protection switch needs to be in the positive cable. If all you are looking for is a way to more easily work on the car, then put one on the neg.
Click to expand...

You have no idea what you are talking about. Sorry. "That's the way it is."

Go draw yourself a diagram of a battery, a switch and a light. "Where" is the ground?" The answer? There is none, or it doesn't matter. Or the positive is ground or the negative is ground. IT DOES NOT MATTER.

If the switch breaks the ground, then the battery is isolated. "Just like" if you break the hot lead

The car "running on" on the alternator IS A DIFFERENT ISSUE and WILL NOT CHANGE depending on where you place the switch
 
If you actually read both my posts you would know that my cars are street cars only and not subject to racing rules and regulations.
They only have to suit me. My 20+ years as a journeyman electrician I happen to know you can break a ground or neutral circuit
and have a safe situation. In low voltage and DC circuits the ground/neutral is the side of the circuit that is often broken. You won't find any fusable links in my cars either. Perhaps you would want to hang around and lurk an learn before you start telling us all what we know.
 
67Dart273 said:
You have no idea what you are talking about. Sorry. "That's the way it is."

Go draw yourself a diagram of a battery, a switch and a light. "Where" is the ground?" The answer? There is none, or it doesn't matter. Or the positive is ground or the negative is ground. IT DOES NOT MATTER.

If the switch breaks the ground, then the battery is isolated. "Just like" if you break the hot lead

The car "running on" on the alternator IS A DIFFERENT ISSUE and WILL NOT CHANGE depending on where you place the switch
Click to expand...
Whatever dude, you’ve never had to pass a tech inspection with a kill switch.
 
General Disarray said:
Whatever dude, you’ve never had to pass a tech inspection with a kill switch.
Click to expand...

We are NOT talking about a tech inspection. STEP OFF. You have no idea here what you are doing.

What are you 12 years old like your avatar? I was driving these cars WHEN THEY WERE NEW
 
67Dart273 said:
We are NOT talking about a tech inspection. STEP OFF. You have no idea here what you are doing.

What are you 12 years old like your avatar? I was driving these cars WHEN THEY WERE NEW
Click to expand...

Nice way to talk to a new guy...so welcoming..:rolleyes:
 
Jimacuda said:
Nice way to talk to a new guy...so welcoming..:rolleyes:
Click to expand...

I tried to tell him but he just won't listen. I didn't see you step in here and explain it to him with biscuits and honey. It ever occur to you? (Look at the screen name) he is a troll?
 
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