12 V Battery Disconnect Kill Switch, Top Post, 250 A Continuous, for Cars, RVs and Boats in Storage
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If you don't love it, return it within 31 days. No questions asked, no restocking fee.
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Park It For A Month. Come Back To A Battery That Still Starts The Car.
A top post battery disconnect switch. It sits between the battery post and the cable clamp, and one twist of the knob cuts the battery off from the whole car. For a vehicle in storage, an RV or boat between seasons, a car with a parasitic drain you have not found yet, or any job where you want the battery out of the circuit before you touch the wiring.
Read This Before You Put One On A Modern Car
Cutting the battery resets the car. Expect to lose radio presets, the clock and trip data every time. Many cars built in the last 15 years also need a relearn after power is cut: one touch windows and sunroofs, the throttle idle, the steering angle sensor, sometimes a transmission adaptation. If your car is one of those, a disconnect switch is for storage and repairs, not for every night in the driveway.
It is not a theft device on its own. It stops a casual attempt to start the car, and that is all; anyone who opens the hood can turn the knob back. For deterrence pair it with an alarm or a tracker.
How To Install It
- Fit it to the negative post. That is the safe side to break the circuit on, and the 15.5 to 17 mm opening is sized for the negative post. Loosen the negative clamp and lift it off.
- Set the switch on the bare post and tighten its clamp so it cannot rotate.
- Put the car's negative cable clamp on the switch's stud and tighten it. Both joints must be snug; a loose joint heats up under starting current.
- Check clearance. The switch adds height above the post. Make sure the hood, the battery cover and any hold down still clear it and nothing metal can touch it.
- Twist the knob to disconnect when you park the car for a stretch or before you work on the wiring. Twist it back and the car is live again.
Specifications
| Type | Top post battery disconnect switch, twist knob |
| Rating | 250 A continuous, 1000 A peak starting current |
| System voltage | 12 to 48 V |
| Fits | Standard top post terminals 15.5 to 17 mm; made for the negative post |
| Construction | Corrosion resistant ABS housing, copper connectors |
| Vehicles | Cars, pickups, RVs and campers, boats, ATVs and UTVs with a top post battery |
| In the box | One switch |
| Weight | About 0.35 lb |
| Warranty and returns | 1 year limited warranty, 31 day returns, US based support from Towson, Maryland |
Frequently Asked Questions
Will it fit my battery?
It fits the round top posts found on most car, truck, RV and marine batteries, 15.5 to 17 mm across, which is the standard negative post. It does not fit side post batteries or the flat stud terminals on some AGM and marine batteries.
My car needs a jump every few days. Is this the fix?
It is a workaround, not a fix. Something is drawing current with the car off. The switch stops the drain while you find the cause; a Voltcheck Pro tells you whether the battery itself is still good, and a scanner with live data helps find the module that will not sleep.
Will my car need anything reset after I reconnect?
On many modern cars, yes: clock, radio presets, one touch windows, sunroof, idle relearn, sometimes steering angle. Older cars, RVs, boats and ATVs usually come back as if nothing happened.
Can it handle starting the engine?
Yes. The rating is 250 A continuous and 1000 A peak, which covers starting current on gasoline and light diesel engines. For a large diesel, mount it and watch that the connections stay cool after a few starts; a warm joint means a clamp needs tightening.
Can I use it on the positive post?
We recommend the negative post. Breaking the negative side is the safe convention, and the positive post is slightly larger, so fit is not guaranteed there.
Will it stop someone stealing the car?
It stops the car from starting until the knob is turned, and nothing more. Treat it as a storage and repair tool, not security.
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Shipping information
Free US shipping on every order, no minimum, with tracking. Orders placed before 2 PM Eastern on a business day ship the same day from Maryland; most US orders arrive in 2 to 4 business days. Worldwide shipping is calculated by weight and destination and shown at checkout before you pay. See the shipping policy.
Returns and warranty
31 day returns, no questions asked. Open it and use it on your car first; if it is not right, send it back for a full refund within 24 hours of the return arriving. YOUCANIC scanners carry a 1 year warranty against defects, repaired or replaced in our Towson, Maryland shop with free shipping both ways inside the US, and software updates are free for life. See the returns page and the warranty page.
