12V on ignition system ?

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Model T Ford Forum: Forum 2012: 12V on ignition system ?
Top of pagePrevious messageNext messageBottom of page Link to this message  By Dick Fischer on Monday, June 25, 2012 - 12:13 pm:

I have always used a 6V battery for the ignition system on my T, hand cranking on battery and then switching over to mag once the engine is running.

But now I'm thinking that it would be much more convenient to use a smaller sealed lead acid battery rather than my usual full sized 6V flooded lead acid. Problem is, those smaller (7AH) sealed batteries are quite common in 12V but not so common in 6V.

So, what is the down side to running 12V for starting ? My car is a hand cranker, so there is no starter to worry about. I can change the stoplite bulb to a 12V. That's no problem. But what about the coils, points and timer contacts ? Do any of the contacts or the coils themselves suffer from the higher voltage and attendant higher current ?

I know the magneto puts out up to 30V once the engine is running, but with hand cranking the timer points remain closed for much longer periods than once the engine is running.

Thanks for any insights,

Dick


Top of pagePrevious messageNext messageBottom of page Link to this message  By Steve Jelf, Parkerfield KS on Monday, June 25, 2012 - 12:37 pm:

I don't see the point. Any added convenience would be so minor as to be negligible. I doubt that I spend more than ten minutes every few months checking the water level in six volt batteries.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jerry Ostbye on Monday, June 25, 2012 - 12:42 pm:

The coils will "as I am told" like the 12 volts better than the six. The 30 volts you are talking about is AC not DC and again, what I have been told that is what the coils were actually designed for.

Looking FWD to more responces on this one..

J


Top of pagePrevious messageNext messageBottom of page Link to this message  By Erik Johnson on Monday, June 25, 2012 - 01:14 pm:

If you want a small sealed six volt battery to put under the front seat or in a running board battery box, use a battery from a Fisher Price "Power Wheels" kiddie car.

They're readily available and last a long time.

I've been using them for years.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Charlie B actually in Toms River N.J. on Monday, June 25, 2012 - 01:17 pm:

I understand your reason for wanting to use the more available 12 vt. sealed batts. They are more common, smaller and alot are spill proof. No reason not to switch. If used as they were meant to be used on a non-starter car, just for starting, It should go a heck of a long time before re-charging is needed. Jerry: I believe that comparison chart that was posted a few months back does show the coils like 12 volts & perform better on it than 6. Dick appears to be looking for some thing more convenient than a wet 6. Think he'll be OK with the change.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Bob Coiro on Monday, June 25, 2012 - 01:18 pm:

I've been running a 12-volt system on my car since purchase and it's been a little over two years, now. So far, no complications due to the 12-volt system (but in the spirit of full disclosure I should point out that my car is of 1915 vintage, so an electrical system of ANY type would be considered a foreign object).

I usually start the engine on battery and run it on magneto. When I switch over to the mag at idle speed, the RPM's drop a tad, which I guess makes sense, as magnetos generate more juice at higher revs. When driving along, engine doesn't seem to care whether I'm on battery or magneto. On battery power, I don't notice any difference in the response of the spark advance control; the theoretical, smooth transition between an infinite number of settings doesn't seem to exist and it still jumps suddenly from fully-retarded to low to medium to fully-advanced. Go figure.

The car doesn't seem to care whether I'm using battery or magneto, but I've heard that the mag is easier on the coils, so that's how I run it.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Steve Jelf, Parkerfield KS on Monday, June 25, 2012 - 02:07 pm:

Of course, on a non-starter car the battery will go longer between charges if it only has to fire the coils when starting but not while running. Another good reason to run on MAG.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Norman T. Kling on Monday, June 25, 2012 - 03:13 pm:

Since you run on mag, and you don't have a starter, a 6 V battery or a 12 V battery will do for the coils to get it started. One won't be any better than the other. If you have electric lights, all the bulbs will need to be changed. I couldn't tell you whether a 6 V horn would work on 12 volts. A bulb horn doesn't care.
Norm


Top of pagePrevious messageNext messageBottom of page Link to this message  By Bud Holzschuh - Panama City, FL on Friday, June 29, 2012 - 11:27 pm:

My mag is bad so I run exclusively on a 12V lawn tractor battery with good starting and performance. It fits nicely under the rear seat of my 15 Touring and I charge it once a month (but I don't use the headlights much).

Lawn tractor batteries are small, easily obtained, cheap and last a long time.

Works for me.

Cheers
schuh


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mike Stitt-Southern Oregon on Saturday, June 30, 2012 - 01:25 am:

As this is a mixed thread and just a comment as my mag is bad here is what I do. I run 12V to the mag wire removed from the mag post. I made a battery charger out of my mag. See Fun projects. I turned my brake light to 12V. The car otherwise is all 6v. I did add turn signals as no one knows what a hand signal is...Well what ever you do they think it means pass me. I went for the highest 6v CP bulbs I could get.
So the car is all 6v otherwise. If you should run the 12v battery low just switch to 6v and putt along. I have never run out of battery and typically charge the 12v battery out of guilt. I'm happy with the results and the cost other than a 12v battery and a few 6v bulbs (higher wattage) is not that expensive.


Top of pagePrevious messageNext messageBottom of page Link to this message  By George_Cherry Hill NJ on Saturday, June 30, 2012 - 07:58 am:

Call it FWIW...

On the '15 which runs great on mag, and will only start maybe one time in 25 on mag when 'cold'...I simply use a 6.3V dry cell lantern battery and manage to get a whole season out of it. Just use it to feed the coils for start, switch to mag once she kicks...couldn't be simpler!


Top of pagePrevious messageNext messageBottom of page Link to this message  By Michael Deichmann, Blistrup, Denmark on Saturday, June 30, 2012 - 11:55 am:

The Model T coil is a constant amps device, which means that regardless of voltage, they will draw (almost) the same number of amps.
That mean that double the amount of energy is consumed, but most of it are (hopefully) put out as more powerfuk sparking, while some of it will heat the coil.
As you only use the battery shortly, it have no effect but a better spark when you crank.
The heat produced is so little, that you may even drive on 12V which many do with no issues.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Charlie B actually in Toms River N.J. on Saturday, June 30, 2012 - 12:05 pm:

As I understand it the only drawback to using DC all the time is the transfer of metal from one point contact to the other. If you recall the older point/condenser systems you'd see a "mountain" on one point contact and a hole in the other. It doesn't happen with AC as the stuff transfers back and forth between the contacts resulting in longer point life. Illusion? I don't know but it sounds right.


Top of pagePrevious messageNext messageBottom of page Link to this message  By tyrone thomas on Saturday, June 30, 2012 - 03:11 pm:

I had a racer. Engine stripped of generator, starter and mag. Ran coils on 6 volt battery. Run ok but sluggush. Than installed a small 12 volt motorcycle battery for coils. Made one hell of a difference in crank starting and running.
Later installed the starter and ran it off of a 6 volt battery. As long as I kept the batteries charged I had not problems.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Bede Cordes, New Zealand on Saturday, June 30, 2012 - 07:23 pm:

Dick,

you have a perfectly good point for a non-starter car. Here in New Zealand, 6 volt car batteries are roughly twice the price of 12. Considering my Dad's non-starter T (mag powered lights) is the only 6 volt running vehicle he currently has roadworthy, so he simply uses a small 12V sealed lead-acid battery as you describe, around 7A/h for starting the T. Once it's started, obviously you switch to mag and the battery's work is done. When warm, often the car can be started on mag anyhow. Having a big expensive 6 volt just for this purpose in this situation would be silly.

You can easlily take the battery out and use a plug-in type power adaptor charger to keep the battery charged when not in use on your workbench etc, or to give it a tickle if it hasn't been used for a while.

This is a cheap and convenient option, the battery is small and you can make a wee box for it to go in, as my Dad has in his T. It works well. The 12V does not worry the coils as outlined in the posts above, and as mentioned, it's only for starting until you manage to switch to mag. (The battery also runs the horn on his T, and the headlights are supplied by the mag, the side/tailights are kero.)

Go and buy yourself one.

Regards,
Bede


Top of pagePrevious messageNext messageBottom of page Link to this message  By mike_black on Saturday, June 30, 2012 - 07:43 pm:

I just finished my 15 and placed a small 12v gel battery under the back seat. Use for starting and for the infrequent use of headlights We discussed this here a couple of months ago about how to wire etc to avoid the mag headlights and use the single contact angled light connectors that I already had. Lights work great, and starts on bat. Only difference I've noticed is, with the lid off, the sound of the coils seems louder on bat until I switch to mag. Engine seems to run the same, but, the coils make less noise on mag!


Top of pagePrevious messageNext messageBottom of page Link to this message  By Bede Cordes, New Zealand on Saturday, June 30, 2012 - 07:53 pm:

PS Dick,

if you are also using the battery for other than starting, like for the OCCASIONAL other thing like a horn, stoplight (change to 12V lamps obviously)etc, you might want to consider this load on the battery, and perhaps go up to a 12A/h for example. Factor in this load and that it will not discharge the battery considering you should have it fully charged before an outing. Most of these lead-acids don't like been discharged below a certain point and won't recover that well.

While you are at it, pop a line fuse at your battery of around 5A or so, just to protect Lizzie against any electrical wiring or equipment failure. Even though those little sealed lead-acids are small, they can still easily deliver enough current under short-circuit conditions to cause fires etc, just like their bigger brothers.

Good luck,
Bede


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dick Fischer on Saturday, June 30, 2012 - 09:01 pm:

Thanks for your comments, guys. I will go with one of the 12V sealed lead acid batteries and be done with it. I was just concerned about cooking the coil points or windings.

The underlying reason for doing this is that I own four vehicles that use a 6V battery: The T, a Model A, and two International tractors. Each gets run only a few times per year. The Scotch part of my ancestry rebels at letting four expensive batteries sit around and die mostly from old age. So for some time I've been keeping only one battery and moving it from vehicle to vehicle. That gets old after a while, especially installing and removing on the T and the A where you have to be careful not to bump the battery against the seats. And that battery gets heavier every year !

Dick


Top of pagePrevious messageNext messageBottom of page Link to this message  By Bud Holzschuh - Panama City, FL on Sunday, July 01, 2012 - 08:10 am:

Here's my system. Nothing wrong with a sealed lead acid, but I chose the lawn tractor battery for the lesser expense and greater amphour rating. 19 Ah if I remember right. I occasionally drive the T home at night using headlights and taillight and I can get 2 to 3 hours of lighting with this battery.

I have since moved the quick disconnect charge connector you see in the photo to an under the hood location as it is easier for me to access it there rather than raise the seat every time I want to connect the charger.




Cheers
schuh


Top of pagePrevious messageNext messageBottom of page Link to this message  By John F. Regan on Sunday, July 01, 2012 - 09:32 am:

The only input I have on your projects guys is a warning. All wood box coils can be damaged by 2 things:

1) Applying power to them without a suitable place for the high voltage to arc to that is less than or equal to 1/4"

2) Allowing them to sit and "buzz" for times exceeding normal start up time. This buzzing of coils causes the coils to draw current at a duty cycle that produces a lot more heat than when the coil is running normally with an operating engine. Buzzing with 12V applied more than doubles the power (heat) that the coil must dissipate. You can in fact overheat a coil via buzzing on 6V too but it takes longer to do than with 12V. So just get in the habit of pulling the crank or stepping on that starter button just as soon as you flip the ignition switch to "Bat". If not starting the car right away - stop the buzzing asap and you will have longer coil life and longer coil point life too.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ron Patterson-Nicholasville, Kentucky on Sunday, July 01, 2012 - 10:03 am:

If not careful John's Item 2 above can result in this. 1
Ron the Coilman


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dick Fischer on Sunday, July 01, 2012 - 01:23 pm:

Thanks, John & Ron, for your inputs. I was hoping to hear from one or both of you. The overheating is just what I feared. There are 6V sealed lead acid batteries available from Batteries America. Maybe that's a safer approach.

Dick


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