Top Post Negative Battery Disconnect Switch 12V / 24V 250/750 Amps Knife Blade Isolator Power Cutoff Switch for Marine Car Boat RV ATV (Horizontal and Vertical)

Robust and awesome Perfect for long term vehicle storage Stops parasitic draw Easy to operate Considerable size and definitely not flimsy You will need to minor modification for battery to switch mount hole and expect to make tightness adjustment for throw switch for your application Saves terminal strip out if working on vehicles a lot connect/disconnect simple flip of switch

We got my son a beater for his first car and somewhere in the electrical system is a voltage leak that I have not been able to find and kills his battery. The car is just not worth the cost of paying a pro to find the leak. Then I came across this rather genius product. This installs in seconds with only the tools require to loosen and tighten the battery cable. You install it on the negative terminal (NOT THE POSITIVE!!!) and as long as the switch is open, the battery cannot be drained because it requires a complete circuit to kill the battery. Since installing this, his battery hasn't died and we don't have to keep jumping his car. There is one downside. By breaking the negative, anything that the car relies on constant power for, like saving radio station presets, will not work. The car is fully electrically dead without the negative.. Not a dealbreaker when weighed against the hassle of jump starting and the cost of batteries, but something to known.

Pro: This works MUCH better than the cheap single-screw battery disconnect that can only pass ~100A... this can pass 10x, for very reliable starting of your vintage vehicle! Metal parts are good quality (copper plated brass castings, brass clips, copper "blade"). Con: More like a kit than a finished product. Fasteners and plastic baseplate are very flimsy, not usable with heavy battery cables. To make useful, I had to screw a scrap piece of 1/4" plywood under the plastic base, and then also solder the brass clips to the terminal castings (electrical solder & propane torch). It is now solid enough to be useable. Took about an hour of head scratching & fabrication.

Works great

Seems to be a quality product. Very easy to install. Fit my battery easily. So far very happy with this.

I bought this for my Chrysler 300C -which has a parasitic power drain I have yet to trace. My car's battery would drain if the car sat for a few days (like a long weekend). I have not had the time or inclination to track down the parasitic drain as work hours have tied up my time. BUT, I could not afford to get stuck with a dead battery in time of need or ruin the expensive battery by it draining dead too may times. SO I would disconnect the negative battery cable when parking -even while at work. But handling the cable and lead battery terminal soiled my hands. THAT'S where this scissor power-switch comes into play. I enter the trunk (using a cord to pull the trunk's emergency release handle), throw the switch to reconnect the car's negative to the battery, and I'm on my way. Now, I will soon get to fixing my car's mysterious power drain, BUT I am already going to install these simple switches as a cut-off switch on a couple other vehicles which are driven very infrequently -to protect batteries from trickle-draining. I find the easiest and safest method is to use the vehicles' negative cable for the cut-off. These terminals can be unscrewed from their support block and swapped if that configuration works better with my vehicles' battery layout. This will extend the life of my batteries by preventing them from draining so quickly to the point where they need to be recharged or jumpstarted. Such deep-cycling will permanently damage lead-acid car batteries VERY quickly. Nice product, reasonable price, will purchase again when the need arises!

My Sonata has a battery drain issue which leaves the battery drained out in 3 days while parked. I traced the issue to the smart junction/fuse box located under the dashboard. Using the ammeter test, the fuse box does not turn off some electronics when I turn off the car resulting to a large drain of 2 amps which should be normally around 50 ma only. After internet researching for Sonata maintenance manual, I learned how to replace/test fuse box myself however it is out of stock. Price of fuse box is around $600 from online dealers but if where to have an Hyundai dealer to buy the part and do the install, they would charge a high $3k for it. So I look around for a cheaper alternative and found this switch. The knife switch is very easy to install and can be installed top down or lying down. It switches smoothly and does not spark when making a connection. My only concern is the somewhat not rigid black plastic base holder of the contacts. Hopefully a better version of this switch using a metallic but non-conducting holder will be use in the future. For now it works great since it was able to solve my car battery issue.

Side post terminals use a 3/8-16 bolt --- the bolt that comes with/installed the disconnect is a metric bolt with the wrong threads. Luckily the threads inside the disconnect terminal are the correct 3/8-16 size and the original cable will screw into it. The incorrect bolt is to be used in the battery which is made of lead and may rethread the battery terminal but you might never be able to reuse the original cable/bolt if you choose the remove the disconnect. I used a 1" x 3/8-16 bolt instead of the bolt that came with the disconnect. Other than the wrong bolt is seems durable

Installed easily and worked as it's supposed to.

Good Itam

I am gonna disagree with some of the reviewers saying that your battery cable won't tighten well on cone shaped terminal. Yes, terminal is cone shaped but I was able to tighten it no problem, I took it over some big bumps and it hasn't moved a hair. One thing that can be improved is a bottom part of the switch, it's made of plastic. I plan to modify this and use a metal plate on the bottom, all you need is a thick metal plate same shape as a plastic on the bottom, drill 2 holes and reconnect the switch, this way it'll probably outlast the car.

Used on an old dump truck with a small short that couldn't be found. Battery would discharge in app 1 month due to infrequent use. Switch took 5 minutes to install and battery stays charged. You have to open the hood to close and open the switch as required. But a cab operated switch would require splicing into and lengthening the battery cables, plus using a more expensive switch.

good product, works well to cut the power between 2 batteries, and isolate the trolling motor.