WirthCo Battery Doctor 20108 Disconnect Knife Switch for Top Post Terminal - 12v Kill Switch for Negative Post - Perfect for Saving Car Battery - Made in USA, black

After reading the negative reviews I was skeptical about the quality (without a reason to be). Well made and does the job perfectly. I believe a lot of the negative comments are from people not holding the isolator tightly when installing and allowing the plastic bottom insulator to take the tightening torque and then breaking. You MUST HOLD THE ISOLATOR TIGHTLY IN YOUR HAND WHEN APPLYING TORQUE TO THE POST CLAMP AND THE ISOLATED POST, NO EXCEPTIONS.The other issue I read was the post clamp broke. Mine didn't, in fact the opening was sized correctly for the NEGATIVE POST AND THE ISOLATOR SHOULD ONLY BE INSTALLED ON THE NEGATIVE BATTERY TERMINAL, NEVER THE POSITIVE.No exceptions to that. You always break the negative side of the battery, NEVER the positive side because breaking the positive side will produce a spark and can cause the battery to explode if it's gassing off which it will do when charging or discharging.Far as I'm concerned the Isolator switch is a quality made component. I see no detractions in quality and if you follow my instructions, the install will be without issues.

Perfect application for 12 volt winch disconnect

Seems decent enough. Works as intended. My only concern is the base is made of plastic and flexes when more than expected when moving the lever up and down. Only time will tell.

In all honesty I had to fiddle with it some on my dual-battery setup but once I got it figured out it works like a champ. This product is simple and super easy to put in place and for that matter, to be removed if you ever need to i.e. cleaning terminals, changing batteries etc.Please be aware this setup is for use on the NEG battery terminal. Make sure you have room to install it where one of your negative terminals are located. It does require a few inches of headspace.My install issue was related to me still having a circuit when I thought I shouldn't. This was when I had both negative battery leads terminating on the knife switch's post (which is installed on the 2nd battery). As soon as I tried putting one of those negative leads onto the 2nd battery itself (while leaving the other connected to the knife switch)everything worked as advertised.As long as this thing lasts a couple of years (min) I will remain in belief it's a necessary and effective little item deserving of 5-stars.

I purchased this item and was disappointed as the item i received did not have the raised Wirthco logos by post and clamp (also another logo on the black plastic piece was missing)--because of this I assumed it was a cheap chinese knock-off and returned it. I bought another online from an autoparts retailer and it too was missing all the trademarks. So I contacted Wirthco and a very nice rep said they now do not have any trademarks or logos--all are plain and assured me these are genuine Wirthco--apparently they make them for other secondary companies. Said those are old images and sellers need to update!Installs easily and works excellent--no more dead battery for an infrequently driven Grand Cherokee.One Caveat--be sure to make sure you have enough hood clearance--thought I did but was wrong--the light assembly on the hood (the light that operates when hood is raised) was interfering with hood closure--had to remove the the light assembly--pulls out easily. Should have purchased the one with the lever that operates horizontally not this vertical one (no i am not talking about the side mount battery post model!).

Bought this to alleviate battery drain on my very seldom used Saturn Sky. The length of the battery cables and the spacing around the battery on the Sky necessitated that I reverse the switch by unscrewing both sides and reattaching them in the opposite orientation. This is straightforward enough, but when reattaching the receiving side of the switch, I accidentally stripped the threading without using much force at all. I was able to salvage the switch using a tapered head nut and bolt, but overall I'm not too impressed with the build quality or design. If the threads had stripped on the side with the lever, I'm not sure there would have been enough room to fit a nut in place. If you need to reverse the orientation of this to fit your application, use care when reinstalling the screws.Installed, it serves its purpose and is easy enough to operate. I had originally tried to fit a screw-type battery cut off but couldn't get the cable to turn and reach the post with that design.

Used this on my 99 Jeep Wrangler Sport as I had a parasitic drawer on my battery, on for a year with no issues.

In our 5er RV we have two group 31 deep cycle batteries with 5/16” studs connected in parallel to the 12V system for extra capacity. They do have the normal top posts as well, but the connections are ring terminals for a 5/16ths stud. It’s impossible to find a proper disconnect switch like this that just goes on the stud, but this was the next best thing because it has a 5/16 inch stud on the expansion side. I can simply screw down the wire with the ring terminal to it without having to redo it for 3/8”!Where it’s stored for months at a time, I like to keep it on an extension cord to keep the batteries healthy, but power is unreliable since someone keeps unplugging it. So to make it a non-issue I just wanted an easy way to disconnect the batteries altogether to eliminate even minimal drain. This is just what the doctor ordered.It was super quick and easy to install, and it’s certainly quite stiff and solid to operate. If the hinge rivets ever one day have a problem, which I doubt, it will be quick and easy to nip them off and replace them with a short machine screw and nut.Grab a couple of 1/2” or 13mm wrenches, and that’s all you need to cinch it down on the top post. Wing but let’s you secure the ring terminals from the RV in place.