Hot Rods Battery cutoff , any thoughts

I've got one on my '39 p/u and one on my '54 Ranch Wagon. From Amazon IIRC. Both Pollak high amp units. The first photo is the switch mounted under the dash on the p***enger side. Don't know why the photo rotated.

 

What is the general consensus, mounted on the Positive or Negative cables ?

 

I have them installed in all my cars. On one car I recently upgraded from low amp unit (100A) to a high amp unit (250A) when installing heavier battery cables. My auto electrician installs them on the positive cable. No terminals are exposed and all have protective covers.

 

That's a 110 amp unit. not enough to trust to run a starter with

the 24213 is 200 amp which may still not be enough but either would be a lot simpler to set up than the little electronic box the op showed and continuous duty solenoids are used on the coach batteries on most motorhomes. Amazon.com: Cole Hersee 24213 12V 200A Continuous Solenoid : Automotive Two wires and a toggle switch make it work from where ever you want to put the switch. That could also be a simple on/off keyed switch.

 

All I can say is, we have been using this unit for 25 years, on perhaps 50-75 cars without a failure.

 

I have one of the plastic switches with a red key in my flathead. been there about 40 years with no problems.
That said, it is obvious from the wide range of prices that quality varies. Buy a "name" brand.
Looked up the Hella book. Rated at 1000 amps for 10 seconds, or 50 amps continuous. I presume these are German amps?

 

It may handle more of a load without an issue than it is rated for then.
A well tuned engine and a great shape electrical system probably don't draw that many amps when cranking than one that has a few issues.

 

We have a remote controlled one in our 50 Chevy Convertible. Think it was from Ron Francis. Works great.

 

I think this is the key to the issue right here. Does the rating of the switch indicate continuous duty or is it for short periods of time, like 10 seconds. You shouldn't be cranking the starter more than 10 seconds anyway, if the engine doesn't start by then, stop and give the starter a break before you try again. A switch that can reliably deliver 1000 amps for 10 seconds is more than capable of the job.

 

Oh, and on the subject of whether to put it on the negative or positive cable, I'm in the Negative camp. But that's due to my years working in the heavy equipment business, and they all have the master switch on the negative cable. I know that's at odds with the NHRA rules though, so if you plan to ever run the car in an NHRA event you probably want to go with their rules...

 

I'm also in the negative camp for the switch. The way I look at it you should always disconnect the ground cable first when changing a battery. If you disconnect the hot cable first there is always the possibility of touching ground with the wrench when removing the positive cable with the resulting spark. JMO

 

Run one on all my cars!

 

Some of these switches look a little M. Mouse, and some are more expensive than the brutally rugged CAT master switch- which also has the removable key. Consider that they are used on enormous machines with huge diesel engines (sometimes dual engines), many times with twin 8D batteries, and I have never seen one fail

 

x 2

 

Instead of using a high amp disconnect, wouldn't it be easier to use a momentary switch in a lower amp circuit? My riding mower won't start unless the parking brake handle is pulled up. Well, its been broke since it was new, about 10 years ago. All it did was push a little ****on for a momentary switch while the engine cranked. I just push the ****on with my finger instead of pulling the lever.
One of my air compressors has a toggle switch mounted on the side of the "starter" box. Simply breaks a low voltage circuit and the starter won't energize. Flip the toggle and it starts pumping. 25+ years on that one

I'm thinking maybe something that could interrupt current to the solenoid. Maybe wired thru a relay and a ****on mounted under the drivers seat. Get in the car and put your hand under the seat and push the ****on as you crank the engine. Its disconnected the rest of the time and only works when cranking. No h***les, no key,no glove box,etc.....