Is a power master switch a bandaid?

[gweilbaker]

Originally Posted by Tom Wesenberg

You'll have to reset all the radio presets each time the switch is turned off and back on. Also the clock will need to be reset.

Not all moderns loose the presets, even the clock, at least in the town and county mini van, which floored me

[gweilbaker]

For all, buy a good quality switch, not the cheap pot metal thing for under 10 bucks. They are a problem and can cause a melt down. Just a heads up. I think "Speedway Motors" offers a good one as well as "Grainger".

[QGolden]

I use these, about 7 dollars, the Green knob disconnects. If I want to I can unscrew it and drop it in my pocket.

[ctvpa]

My fuse has saved me many times.
1) Look and almost any repair and the instruction start with "disconnect the battery. People who don't have a kill switch, remove the carpet, unscrew the floor board and disconnect the batter, unless they have enlarged the hole. But it still adds time to the project.
2) I had a short in the brake light switch. The fuse blew, and saved my wiring.
3) I had a short in the dash, and by the time I got to disconnect the power, the harness was burned to a crisp.
All around I will put one in every car I own.
By the way, if you get the mount that bolts under the starter, the ignition "On Off" fits on it and works well over the switch.

[QGolden]

Originally Posted by ctvpa

By the way, if you get the mount that bolts under the starter, the ignition "On Off" fits on it and works well over the switch.

Hi,
Can you expound on this a bit? Do you have a photo?

[Bruce Adams]

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Originally Posted by QGolden

I use these, about 7 dollars, the Green knob disconnects. If I want to I can unscrew it and drop it in my pocket.

The Green Knob switches are generally POT METAL which can break at the worst time. Following two failures I now have the top shelf brass switch installed above the starter rod so I can flick it off and on with my foot.

[Mitch//pa]

Originally Posted by Bruce Adams

The Green Knob switches are generally POT METAL which can break at the worst time. Following two failures I now have the top shelf brass switch installed above the starter rod so I can flick it off and on with my foot.

Agree they are junk have seen many fail
Plus getting to it is a PIA

[kcav8or]

I recently bought a switch, but what's the best location for installation? My brother-in-law partly installed it on the front floorboard before we ran out of time. But then I found the instructions for the switch bracket that says to install it in the engine compartment. Seems that an inside installation might be more convenient.

[1931 flamingo]

A "kill" switch is not a necessity UNLESS you believe in Murphy's Law. It's cheap insurance, especially IF something goes wrong. As Mitch stated, it takes precious moments to gain access to the battery, find the correct wrench and disc the batt in case of a short.
Mine is mounted under the front seat, easy access, convenient and gives me peace of mind. FWIW
Paul in CT

[George Miller]

Originally Posted by kcav8or

I recently bought a switch, but what's the best location for installation? My brother-in-law partly installed it on the front floorboard before we ran out of time. But then I found the instructions for the switch bracket that says to install it in the engine compartment. Seems that an inside installation might be more convenient.

I put mine on the inside. If you put it under the hood that means lifting the hood every time you drive. As much as I drive my car it would be a pain in the bu.

On my sports coupe there is room at cross member at the back of floor board at the edge of the seat.

[SDJason]

If you search the forum (use the advanced search function and look for "battery" and "switch" in the thread title only) and you'll come up with numerous previous discussions on this subject . Here are links to a few of them:

"Battery switch placement"

"Battery disconnect switch"

"Battery Shutoff Switch"


(note - this is why I prefer that people use a descriptive title for their threads - cutesy, vague teasers are absolutely useless for helping out anyone trying to find that thread later; yes - you can try searching the entire post instead of just the thread title, but that's nearly useless too, as the number of matches in the results will be enormous:

e.g.:
searching for "battery switch" in just the thread title: 9 mostly relevant results
searching for "battery switch" in the entire post: 500 not-so-relevant results

[H. L. Chauvin]

Interesting Question: Is a power master switch a good band aid?

1. Appears a band aid is used most often for very minor cuts & minor skin abrasions which are not very serious and do not require immediate medical attention.

2. However, a power master switch can be thought of as a safety device used to separate a spark igniter from a volatile fuel supply; or maybe a safety device to separate the highly explosive, sensitive blasting caps from a demolition expert's powerful dynamite sticks.

3. Whether or not one may have mice or squirrels chewing on wire insulation, in any case, it appears that trying to explain the relationship between band aids & power master switches would be difficult depending on the experience of Model A owners & the condition of their existing 80+ year old fuel systems & existing wiring systems.

4. Even though a controversial subject without one (1) definite answer, one thing appears certain that most would agree upon, i.e.:

If one finds out later that a Model A power master switch could have saved his previous prized Model A , his former new two car garage filled with new fishing rods, & his huge house with his gun collection, that all went up in smoke, "all" because of a Model A electrical fire, he would definitely be just a little more prone to install a power switch on his second Model A, & probably only if his wife allows it.

Not trying to be pro or con, just hope this helps somebody to make a decision -- each to his own as far as life's choices.

[Bill Goddard]

I have a related question. What wire gage (size) should be used for a 12v system. I have been looking in stores for a set of battery starter cables and the size ranges from 4 ga down to 10 ga. Why are we using sizes like 00, 1,2 for the model As - or how can the starter cables get by with lighter gages? 00, 1,2 are so big and stiff it is hard to route around the frame. Seems the starter cables should be big because they are longer and in the car wiring could be smaller because they are shorter. Bill G

[Mitch//pa]

Originally Posted by Bill Goddard

I have a related question. What wire gage (size) should be used for a 12v system. I have been looking in stores for a set of battery starter cables and the size ranges from 4 ga down to 10 ga. Why are we using sizes like 00, 1,2 for the model As - or how can the starter cables get by with lighter gages? 00, 1,2 are so big and stiff it is hard to route around the frame. Seems the starter cables should be big because they are longer and in the car wiring could be smaller because they are shorter. Bill G

if your talking jumper cables they are to just carry some amps into the existing car battery. they need to be used in conjunction with the original cables not instead of....
I would buy the heaviest ones available 4 ga being the thickest

[Patrick L.]

As Mitch said, regarding jumper cables, get the heaviest available.

Regarding the vehicles wiring, 12v requires far smaller wire size than 6v. Oversizing wire really doesn't hurt anything, while undersizing does. The car builders saved fortunes by going to 12v just in wire sizing.

[Bill Goddard]

Does someone have an equivalancy chart. i.e if 1 ga will handle 200 Amps at 6v, what ga will handle 100 A at 12 v? Bill G

[Bill Goddard]

I found my answer in "Boat Owners Mechanical and Electrical Manual" by Nigel Calder. He shows a chart giving current draw vs. length / dia. He gives for 3% voltage drop at 12 v: 4 ga wire for 10' to/from at 100A. So I assume the 4 ga battery cables I see in the auto store will work.

[Allanw]

Originally Posted by 1931 flamingo

A "kill" switch is not a necessity UNLESS you believe in Murphy's Law. It's cheap insurance, especially IF something goes wrong.

Exactly.

If you don't like kill switches, why use the petrol tap??? It's not necessary to turn it off, if all is in good condition

Modern cars are very different. Our old BMW has about 60 fuses for different things. On the A, the fuse is VERY large for the size of some of the wiring, so it's not always going to protect all the wiring. I'm planning on fitting a small discrete fuse box to fuse individual loads - if there is a fault, only one load loses power. Imagine losing power to the headlights, ignition, brake lights and wiper all together ... at mignight in the rain...

Hands up if you'd be happy to leave a 80+ year old mains heater running in your living room while you went out

[Marco Tahtaras]

Originally Posted by ctvpa

My fuse has saved me many times.
1) Look and almost any repair and the instruction start with "disconnect the battery. People who don't have a kill switch, remove the carpet, unscrew the floor board and disconnect the batter, unless they have enlarged the hole. But it still adds time to the project.
2) I had a short in the brake light switch. The fuse blew, and saved my wiring.
3) I had a short in the dash, and by the time I got to disconnect the power, the harness was burned to a crisp.

Well that has me a bit confused! What was wrong that the fuse didn't blow? That's why it is there if you have one!

[Mitch//pa]

Originally Posted by Marco Tahtaras

Well that has me a bit confused! What was wrong that the fuse didn't blow? That's why it is there if you have one!

all shorts are not created equal for instance if the bad circuit is shorted against something with a higher resistance, it may not over come the fuse, but can still melt the wiring sorta like a slow burn. have seen it on modern iron lots of times....