Battery Disconnect Switch

Have used them. Good in theory. Bad in practice. They cross thread too easily. I've gone this route. Not the cleanest installation but it works.

I’ve got a heavy duty Marine disconnect mounted on the firewall behind the battery.

it’s connected to the negative terminal and so therefore it’s a very easy routing.

I’m on vacation now, but I’ll try to remember to post a picture. I use mine all the time.

Rocky

I have the style you show on my Pantera for 13 years, no issues, you don't need to remove the knurled nut just loosen it, so not sure how it cross threads?

Same with me, I have had the Green Knob type on my car for 10 years, no problems.  Not sure how you could cross thread this thing.  It goes on the negative battery terminal.  Some guys think it goes on the positive.  that is wrong.

I appreciate the feedback.

Here's a picture of my setup.

You can see by using the Negative cable, the runs are much shorter, and pretty easy to route.

@rodman posted:

Hello,

I don't use this forum often so I hope I'm posting this in the right place. I want to install a battery disconnect switch on my 72 DE Tomaso but am not to sure on amp ratings. I mean when looking I see in the description column, Continuous amp rating 100 amps, Surge amp rating 125 amps. To be quite honest, I'm a pretty damned good parts changer but by far not a mechanic and definitely not savvy to anything electrical . The one I'm looking at is on the summit website and is shown in my attachment. In short, will this work or can someone that knows what they're talking about help me out?...Any help would be appreciated...

Thks...

 

Over the years I use this type of switch too , there are good quality produced and bad (Chinese) produced . Price dont say anything about the quality , I have failed expensive and failed cheap switches.

Some of them have bad quality cast bronze and are broke.

Only a small surface is used for connect or disconnect , when this surface is pitted there is a problem while starting.

Simon

I have used that same switch pictured by you and used by Joules for many years with no problems, and I also changed to a front terminal connection battery for more clearance and a more compact installation with a shorter negative cable length.

Some things to consider when using these battery mounted disconnects:

As Simon posted, the quality varies among manufacturers.  Some of these disconnects are cheap die cast poor quality base metal that is brass plated.  Others are cast brass with a very high zinc content that breaks easily.  

This type of switch consists of three conductive parts:  1) the battery connector, 2) the battery cable connector, and 3) the connecting stud (with knob).  When the disconnect knob is unscrewed on some of these, they will separate into the their respective pieces.   With this design, and with the disconnect's knob partially  unscrewed,  should one accidentally bump the battery cable when working near the battery, the disconnect pieces could come in contact with each other and reconnect the battery to the car's electrical system, potentially ruining your whole day.  

The disconnect switches made by Gama appear to be of good quality.  The parts are crimped so that they are firmly retained when the disconnect knob is loosened, and there are two types available.

The electrical contact area of these types of disconnects is relatively small and will cause a voltage drop during high current conditions such as starting the engine.

Personally, I use a marine grade battery disconnect switch.  The one that I use is made by Blue Sea Systems and has a 250 amp continuous / 375 amp intermittent  rating.

John