Top Post Battery Master Disconnect Switch

Worked good on my 2015 Honda Pilot, keeps my battery from draining until I can find the parasitic drain problem.

The product seems very sturdy, and very easy to install in the vehicle. However, I do recommend *also* purchasing some inexpensive conductive battery post shims, as this product's male post (which you attach your auto or truck's negative battery cable to) may be a bit too narrow, depending upon the size of the opening of your car or truck's battery cables. In my case, the product's post was too narrow for the cable opening, so I cut off a small piece of battery shim and after a few moments of adjusting to create just the right size shim, it fit perfectly - but again, I *did* have to monkey around with it for a few minutes, and this exercise I am describing was not included on the product's instruction card. So, have your wrench/ratchet for battery disconnect handy, and also have some heavy duty scissors or needle-nose pliers for cutting the shim(s) if you need to. Thankfully, I had read a critical review from another purchaser ahead of time and ordered the shims at the same time I ordered this product.Overall, this seems to be an excellent way to cheaply and effectively install a battery kill switch. At least, it is doing the job for my old 1996 Jeep Grand Cherokee. Yes, raising and lowering the hood is a nuisance, but less of one than trying to start a car with a dead battery. I am writing this the same day that I received the product, so time will tell if this buy makes for a good, long-term fix.

My Jeep is 25 years old and has a terrible parasitic draw. So much that it will kill the battery overnight, sometimes within hours. With the vehicle being this old I don't have time to diagnose and potentially end up having to rewire stuff. Installation was super simple and it fit like a glove on my terminal. Functions like it should. Not sure why so many break but I have a sneaking suspicion that some customers may be overtightening.

Installed this in a 50 years old Toyota that is mostly garaged and to prevent battery damage due to frequent discharging. It installs in 10 minutes, works exactly as intended and in my case it takes half a turn to completely cut power. There are only two minor issues and hence the 4 stars:1. If not very tightly screwed, I can see vibration loosening the bolt and causing the negative to disconnect. It hasn't happened, but adding a failsafe while driving (e.g. a pin) would be a much better design.2. There is a slight voltage drop, which is normal as you're adding joints to the negative cable. I measured around 0.3 volts less with this switch in place. If your alternator is weak this could be a big deal.

How does it work? This switch is a very simple concept and works great. I wondered if it slides or not, but it doesn't.Here is how it works. The bottom of the part is brass and connects to the battery cable. The top of the part is brass and connects to the battery post. There is a plastic insulator between the two parts. They are securely mechanically crimped together by a hydraulic press in the factory. To connect the two and allow current to flow, you tighten the brass bolt with a plastic knob. The screw goes into tapped threads in the lower part. Tightening makes contact with the upper part. The current flows through the bolt from one part to the other.As others note, always attach this only to the negative, or minus (-) side of the battery. The switch fit nicely to both my Interstate Battery and my Dodge Grand Caravan. The reason to connect to the negative side only is that the majority of the car (all the frame and body parts) is negative. Only half of the wires are positive. Should you drop a tool on this and another part, or even if your hood had such low clearance that the hood bumped it, or if you touched this against another part of the car, you won't get a short. To avoid these various problems, the positive post is made larger, and this switch won't fit on the post unless you damage the switch by spreading the clamp.

Easy to install, easy to operate and great price. Bought one for my car and another one a couple of weeks later for my wife’s car. This is so well made seems it will outlast multiple cars.

Great quality brass easy to setup clear instructions and fits most cars batteries. It’s saving the battery of the car that just sits for weeks.