Battery Disconnect
 

I see a number of historic threads on this topic but am still having difficulty. I intend to install a Snyder battery switch on my 29 roadster, using the Snyder mount that is intended to be located on the starter/flywheel bolt. I also purchased the lead wire suggest for this setup. Even with pictures from old threads, I can't figure out the wiring diagram needed to do this work. This is a 12V negative ground setup. I know this can't be as hard as I am making it.
Can anybody furnish a little diagram for an electrical dunce?

Thanks.

Re: Battery Disconnect
 

For that setup, the basic answer is:

1) remove battery cable from starter motor, attach it to one of the terminals on the disconnect switch

2) connect the new lead wire from the other terminal on the switch to the starter motor where the battery cable used to be

This is without getting into the debate on which side of the battery should be used for the disconnect.

Re: Battery Disconnect
 

Doug,
You may be over thinking this. No gewizz electrical stuff here, just putting a switch in the cable to the starter. Here is what I did recently. I removed the grommet on the clutch housing and rerouted the cable down and along the frame rail. Used a chassis clip to hold the cable in place.
Take the short cable and run it up between the block and starter.
The plate on the switch can be hard to read so I got a red and green paint marker and marked a line under the switch handle, red for off and green for on.
A side note, good to run a battery cable from the battery cable frame bolt to the transmission. I think a 19 inch cable with eye lugs on both ends is what I used.

Good luck, hope this helps,
Ed

Re: Battery Disconnect
 

Just be aware that putting the switch in the hot cable the wire from the battery to the switch will always be hot even with the switch off. If you put the switch in the ground cable when you have the switch turned off everything will be off. Just a safer way.

Re: Battery Disconnect
 

You might also do a search on this forum for disconnects mounted inside the cab as there are many who have done it. Beats having to lift the hood whenever you want to disconnect the battery. Ditto on mounting it on the ground side.

Glen

Re: Battery Disconnect
 

I mounted mine using the bracket and jumper cable that the vendors offer.

Got a long battery cable from the auto parts store and ran it from the battery ground post to the switch, and then the short cable from the switch to the upper starter mounting bolt.

I also ran an old choke cable from the switch lever into the cab so I can turn the switch off from inside.

Re: Battery Disconnect
 

Thanks everybody. I think I get it. One of the things I was having difficulty understanding was how the switch could be bolted to the starter/flywheel bolt without automatically being grounded at all times. The internal workings of the switch must break the ground in spite of the body of the switch being connected to ground.

Re: Battery Disconnect
 

I like the idea of the terminal boots, nice clean installation. I also think the choke cable control is an excellent idea, I can see how pulling the choke control would move the switch but how does pushing the control move the switch? Am I missing something in the picture? Two really good ideas

Re: Battery Disconnect
 

Replace the battery cable going to the starter with two cables, one from the battery to the cutoff switch, and the second from the cutoff switch to the starter switch.

The easiest mount for the cutoff switch is the engine mount on the battery's side. Use the existing hole in the engine mount to attach the cutoff switch.

Re: Battery Disconnect
 

The old choke cable only works to shut the power off. I figured it would be nice to be able to shut off the power immediately if something went wrong. Someone had already made a hole in the cab subframe.

The cable is pretty stiff but not stiff enough to turn the switch back on.

I always check the oil on the first start of the day so turning the switch on at the same time is simple enough.

Randy

Re: Battery Disconnect
 

Bob Bidonde: I like your mounting solution a lot. Thx

Re: Battery Disconnect
 

My car is still 6V positive ground. I've been having trouble with the battery going dead while the car is parked for a week or so. Figure turning the battery off while parked will help rectify the situation.

Seems to be some debate about which side of the battery to install the disconnect switch on. For my particular case am I ok installing the switch between the hot negative terminal and the starter?

Re: Battery Disconnect
 

The switch should be on he ground side, that's how it's done on heavy
construction equipment.


Bob

Re: Battery Disconnect
 

I fully agree. I recently pulled a spark while working on a friend’s car by allowing a wrench to touch the disconnect post (mounted on the firewall) and a head bolt at the same time. The disconnect switch was in the “hot” side of the battery.

Re: Battery Disconnect
 

I have never seen a good reason to put the switch in the hot side.The cable from the battery to the switch stays hot,and that is where I have seen the troubles.I saw an A that had the switch mounted on the firewall,he could just kick it with his toe from the drivers seat.On that one the cable pulled out of the eye,and dropped.It hit the spark rod on the way,that didn't present much of a challenge for those amps,it cut it in half like butter.It came to rest on iron somewhere and just melted.Nothing caught on fire but the battery blew up.I saw one in one of those lollipop brackets the vendors sell,it broke from the vibration,dropped and shorted.On that one the car just died so he tied it up and kept driving.

Re: Battery Disconnect
 

Just add a fuse to the starter terminal for a simple disconnect - lift one side of the fuse. But the battery disconnect switch it is best placed on the ground side instead of the hot, for the reasons mentioned above.

Your battery is probably due for a replacement, but a small smart charger/battery maintainer might keep it going, and they don't cost very much. I just bought 2 on Amazon to keep my two "standing" cars charged up.

Re: Battery Disconnect
 

Something else I just thought of,you will probably spend more time fitting a kill switch than finding and fixing the real problem.But,kill switches are a good idea so it isn't time wasted.

Re: Battery Disconnect
 

These are great ideas Badpuppy. Thanks. Will try this for a short term fix and then hook up a disconnect on the ground side of the battery.

Re: Battery Disconnect
 

__________________________________________________ _______________

In my '31 Tudor I mounted the switch in the floorboard right side front of the driver seat. Convenient to "kill" whenever I leave the car. I also turn off the fuel when leaving, even for only minutes.

Re: Battery Disconnect
 

I put mine on the seat riser on my 30 coupe