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

good

A nice switch. I installed it on my yard truck that never goes out on the road and does plenty of sitting during the year especially the summer. This should save the battery. Seems to be made well. I coated the whole thing with dielectric grease to prevent any corrosion. Was a breeze to install. Plenty of hood clearance with this model as it opens horizontally. Installed on a 1972 Ford F-250 4x4.

Great price, easy YouTube videos on how to install and works as advertised.

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.

sturdy switch, positive connection. Other switches have lost their connection and had to be reset. This one seems to hold with no problems.

Quality product, quick and intuitive installation... on certain cars. Wish there were an equivalent product that worked on vintage cars with positive ground systems and top-post batteries. That means 6v and even some 12v systems up to the mid-1950s. On my car there's too much risk of arcing if installed on the negative battery post; no way it will slip onto the larger positive post. I just tried again. It goes back into my box of unusable (for me) stuff. My switch (purchased a while back) oddly had the tip of the blade covered in red rather than black. Update: OK, I stopped feeling sorry for myself, took the switch out of that box and easily installed on a similar car (one model year newer), but one with twelve volt negative ground. Works fine. But that still leaves the older car (which has had unexpected and unexplained electrical drain issues recently) with no disconnect switch. I thought the WirthCo 20251 "quick release" bolts might be a solution. They weren't. (Reviewed separately.) So I will manage with a 1/2" wrench kept under the front seat. So I've restored the missing star to my rating. Hope everyone realizes that it's for negative ground systems ONLY. Would appreciate an occasional small production run of these sized for older positive ground cars! Attempting to use this switch on the negative post on such vehicles is potentially dangerous.