The Stovebolt Site Forums The Shop Area The Electrical Bay Battery Cut-Off Switch

I want to install a battery cut-off on my 49. On my 53 I had one which was under the seat and the on/off knob came through the seat valance.
It is basically a safety thing in case of shorts and fires. When I store the truck I disconnect the battery but that involves going under the floor.
On most switches I've seen there various ratings and such but they are greek to me. Can someone explain. I would assume that there is not continous current going through the switch once the engine has started. I have no accessories requiring constant battery power.

Bill,

A switch is rated for the amount of current the contacts will pass. Your cut-off switch will probably be in series in the positive battery cable, so it will have to have a rating that is more than maximum your starter would see when you start the truck.

Your starter would probably never pull more than 250 amps on its worst day, so that would be a rating to shoot for. I have seen those disconnect switches, and I actually have one in the shop somewhere.

The switch I have is a army olive drab with large lugs on the back. To disconnect, you pull up and twist and the switch remains 'open'. Twist again and let it snap down and it 'closes'.

Is this what you are talking about. My switch has a nice mounting flange so it can be mounted on a flat surface with the knob out and the business end on the other side of the panel.

Look at this beauty...and reasonable too!

http://www.amazon.com/BATTERY-KILL-...IKX0DER&pf_rd_r=1Z1V5HXHKXYDZCB4C8EF

Another cool one.

http://www.moroso.com/catalog/categorydisplay.asp?catcode=42225



Stuart

cole-hersee co.

Battery Disconnect
Master Disconnect Switches protect against theft, accidental starting and battery drain. We have switches for 125A through 2000A!
http://www.colehersee.com/catalog_top/index.htm
find ........ battery related ... under products list.

I have a battery cut-off switch in my truck. I like it because the "knob" is removable. That way no one can just turn it back on. No hot wiring, no jumping, no electrical use when I am not there.

I bought one like that in the first link Stu, cept I paid $35 at my local flaps for it. Been kind of holding off because I don't want to run yards of 2/0 cable to put it inside.
Been thinking about mounting it to a plate bolted inside the frame where the cable crosses over. That would keep the length the same by just having to split the cable and solder a couple of new terminal ends on them. Only draw back to this location is that I would have to crawl under to switch it on/off and of course there is always the problem with it getting wet. Point is I just don't want it to show from the topside-inside or under the hood.
Denny Graham
Sandwich, IL

I use one up under the seat where it's out of site. I shut it off every time I get out. Not so much for safety but as security. All drag racing cars require them so check the speed shops. Joe

I'm trying this relay
http://www.wiringproducts.com/index...=search.html&lmd=0.10867724227579989
I am just switching the starter with it.. My plan is to keep the kids from stepping on the starter while the key is out. They have a 400amp switch but this is more fun. I used one to add a second battery to my driver and it already saved me once..

4D6, your link is to the search page.

Oops, it is R-200A... A 200A relay switched by a 12v source..

4D6,

When you get this relay, could you tell us if the spec sheet with it indicates it can sustain continuous duty on the hold-in coil. The poop sheet on the web site isn't clear on this important point.

Stuart

Stuart what your are describing as having in the shop is what I mean. I checked out the auto parts stores and they range anywhere from $65 - $100 which I think is mighty steep. Basically because its got some speed equipment brand on it. Someone suggested a marine supply house should have and they do but not the metal type. They sell for about $35.
I will check the links posted above and see what the numbers are on their products and then get back.
Thanks

I just checked the Ron Francis Wiring site and their MS-1 is what I think I need.

I can't find a spec sheet.. The one I have in service now switches in an aux battery on my 2002 chevy. I turn it on for days at a time (charging). I used it once when my other battery got too low and the relay didn't smoke.. I'll keep looking for a spce sheet though, I'm sure it is in my shop somewhere..

I have found over the years that some battery switches described above have eventually faulted by there constant use. I have changed to using the remote battery cut-out similar to part number MS-21 on Ron Francis Wiring site. These rely on a mechanical latch in the off and on position not electrical so no power is drawn.
These units are controlled by a push button that can be hidden anywhere that only the owner will only know about. No extra battery cable , just break into the existing positive cable and mount unit.
The only drawback with these units is if you have a radio/CD player with a memory. This will be lost with each aplication of the push button to isolate the truck wiring from the battery . To overcome this, the supply to the push button , which is always live as it is feed by the battery side of the MS21, can also be used to supply 12v to the radio keeping the memory active even after isolating the truck wiring by aplication of the push button. Remember to fuse the cable to the push button / radio memory as it is fed by the battery.
These units are used for example by people leaving a houseboat empty for a few days/weeks. Look around before purchasing over here in Oz they are about $80 > $50 in your money

That's great info...a mechanical latch. Thanks for giving us the 'rest of the story'.


Stuart