12v aux battery for coils while keeping 6V for all else

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Model T Ford Forum: Forum 2008: 12v aux battery for coils while keeping 6V for all else
Top of pagePrevious messageNext messageBottom of page Link to this message  By Adrian Whiteman on Sunday, January 25, 2009 - 10:21 pm:

I am looking at improving spark performance, and recall various suggestions as to adding a second battery to give more oomph to the 6v standard.

Here is the proposed temporary setup, your comments are welcome:

* install a 12v battery as an auxiliary - not connected to anything but the mag post
* I don't have any coil plate or magnets installed
* earth the 12v battery to chassis - along with the 6 v battery (both positives).
* switch to "mag" when going to get 12v juice to coil.
* leave the 6v battery connected to lights/horn etc. and generator cutout.
* charge the 12v battery with battery charger as needed.

Basis: easy and quick install, and leaves everything in place and untouched. No "12v" issue on the starter either. When engine is rebuilt (this winter down under) coil plate and magnets will be installed, so the solution is easily removed.

Are there any problems having the 12v and 6v systems on a common earth?

Cheers
Adrian


Top of pagePrevious messageNext messageBottom of page Link to this message  By Bob Jablonski on Sunday, January 25, 2009 - 10:32 pm:

Adrian:

Earth the negatives of both batteries.

This way the ammeter will show a positive charge when running.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Harold Schwendeman on Sunday, January 25, 2009 - 10:55 pm:

Adrian - I have the exact same plan for my '23 roadster as it has, and HAS HAD for many years, a weak magneto, probably due to excessive crankshaft end play. Ron Patterson ("Ron the Coilman") has just rebuilt a set of coils for me, and I have talked this plan over with him and he thinks it's a great idea. I had the same question about a common ground for both the 6v battery and the 12v battery on the same car, and others (including Ron the Coilman) assures me that there's no problem with doing that. My only decision now is what type and size 12v battery to use. For "compactness", I'm considering looking into motorcycle batteries and garden tractor batteries, but also considering an "Optima" battery, due to quality and the fact that they do not have to be mounted necessarily level and right-side-up which should afford more of a variety of mounting places/positions. One question I have, (that I did not think to ask Ron) is whether or not a "deep cycle" battery would be a good idea for the 12v battery, as it is more likely to become discharged to a greater degree than a battery that is normally kept fully charged by the vehicle generator (or maybe some day, alternator) instead of an occasional charge with a battery charger in the garage.

Thanks for starting this thread Adrian, and maybe between the two of us, we'll get some others to "chime in" here with some ideas! (???)

By the way Adrian, I seem to recall that John Regan has mentioned in the past that he runs his coils off of a 12 volt battery instead of the magneto, and has for some time. I figuer that that's good enough for me, knowing John Regan's reputation and knowledge and experience with "things electrical", as well as the quality of the products that his company (Fun Projects) builds.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Adrian Whiteman on Sunday, January 25, 2009 - 10:57 pm:

Thanks Bob


Top of pagePrevious messageNext messageBottom of page Link to this message  By Adrian Whiteman on Sunday, January 25, 2009 - 11:02 pm:

Harold, many thanks for the encouragement.
I have a "homebuilt" battery box under the deck of my TT, so size of the battery is not a problem. I will use a "standard-ish" Japanese car size battery.

I can't take credit for the idea though - brighter brains that me suggested it.

Cheers
Adrian


Top of pagePrevious messageNext messageBottom of page Link to this message  By Adrian Whiteman on Monday, January 26, 2009 - 06:39 am:

All connected up and operational.
Noticable improvement and more pep - just by switching from battery (6v) to "mag" (12v).
Took only a few minutes to set up and dead easy to do.

Cheers
Adrian


Top of pagePrevious messageNext messageBottom of page Link to this message  By Adrian Whiteman on Monday, January 26, 2009 - 06:40 am:

(with both batteries grounded on Negatives too)


Top of pagePrevious messageNext messageBottom of page Link to this message  By rdupree on Monday, January 26, 2009 - 08:31 am:

Adrian,

Sounds like your 6v/12v system is working well for you. Some of the Model A people around here do things a little different. If you install a 6v battery in series in the ignition circuti, you will still have 12v for the coils, and 6v for the rest of the car, but with minimal modifications to the wiring. The Model A guys do this for things like a CB radio. Simpler and lots cheaper than a 6 to 12 volt voltage converter.

Ron Dupree


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ron Patterson on Monday, January 26, 2009 - 12:31 pm:

Adrian
Here is a link to an article that explains why coils work so much better on 12 volts DC than 6 volts DC and why running on the magneto works so much better than on 6 volts DC.
More on Model T Spark Timing
Ron the Coilman


Top of pagePrevious messageNext messageBottom of page Link to this message  By John F. Regan on Monday, January 26, 2009 - 12:33 pm:

Adrian:

My son ran a 12V battery in his '16 roadster for a couple of seasons because the mag was dead. It worked fine and the car did NOT have a starter so no problems with bendix. We rebuilt the engine, fixed the mag and did end up putting a 6V ssytem and starter on the car because of all the traffic around here that we have to drive in. Killing the engine in the middle of a busy intersection full of Chicago drivers can be a death trap ha ha. Now don't all you Chicago guys get mad at me - I jest. Ron Dupree's method will work equally well too.

The only point I want to make is that the ignition system when engine is running draws about .65 Amps TOTAL so you don't need a huge battery for this application of "ignition only" battery. A typical garden tractor 12V battery sold at home improvement stores is usually 20 Amp-hour capacity and that will run your T all day long. I do agree that you need to get in the habit of immediately recharging whatever battery you use or the battery will not last very long. Unfortunately most of us when we come home from a tour will make the decision to put the battery charger on the car "tomorrow" - and "tomorrow" becomes 2 weeks later when we want to go for another ride. That will spell very short life for the battery. Optima is a great battery but might be more than you need if you can find a nice neat place to mount a "regular" battery upright. If you do go with the optima - be absolutely sure to recharge it after every use. It is a lead acid battery will all the same limitations with regard to being damaged if left in discharged state. Kept fully charged they last a very long time but left uncharged they have same short life of any other lead acid battery. Actually while I agree that you should likely wire up everything as negative ground, this extra battery will not have any affect on your ammeter readings regardless of whether you wire it up negative or positive ground. Only the main battery charge current will go through the ammeter. The T electrical system will not even know the other battery is there.


Top of pagePrevious messageNext messageBottom of page Link to this message  By John F. Regan on Monday, January 26, 2009 - 12:36 pm:

Adrian:

My son ran a 12V battery in his '16 roadster for a couple of seasons because the mag was dead. It worked fine and the car did NOT have a starter so no problems with bendix. We rebuilt the engine, fixed the mag and did end up putting a 6V ssytem and starter on the car because of all the traffic around here that we have to drive in. Killing the engine in the middle of a busy intersection full of Chicago drivers can be a death trap ha ha. Now don't all you Chicago guys get mad at me - I jest. Ron Dupree's method will work equally well too.

The only point I want to make is that the ignition system when engine is running draws about .65 Amps TOTAL so you don't need a huge battery for this application of "ignition only" battery. A typical garden tractor 12V battery sold at home improvement stores is usually 20 Amp-hour capacity and that will run your T all day long. I do agree that you need to get in the habit of immediately recharging whatever battery you use or the battery will not last very long. Unfortunately most of us when we come home from a tour will make the decision to put the battery charger on the car "tomorrow" - and "tomorrow" becomes 2 weeks later when we want to go for another ride. That will spell very short life for the battery. Optima is a great battery but might be more than you need if you can find a nice neat place to mount a "regular" battery upright. If you do go with the optima - be absolutely sure to recharge it after every use. It is a lead acid battery will all the same limitations with regard to being damaged if left in discharged state. Kept fully charged they last a very long time but left uncharged they have same short life of any other lead acid battery. Actually while I agree that you should likely wire up everything as negative ground, this extra battery will not have any affect on your ammeter readings regardless of whether you wire it up negative or positive ground. Only the main battery charge current will go through the ammeter. The T electrical system will not even know the other battery is there.


Top of pagePrevious messageNext messageBottom of page Link to this message  By John F. Regan on Monday, January 26, 2009 - 12:38 pm:

Not sure how I double posted. It's hell getting old. Ron you best take over at Chicasha! - I might forget the pizza or double the order by mistake.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ron Patterson on Monday, January 26, 2009 - 12:53 pm:

One additional caution. The coils will work fine running the engine on 12 volts, but do not let them buzz continually (more than one minute) on 12 volts when the engine is not running. They will get very hot and the tar will start leaking out of the wood coil box.
Ron the Coilman


Top of pagePrevious messageNext messageBottom of page Link to this message  By Adrian Whiteman on Monday, January 26, 2009 - 08:53 pm:

Thanks for the pointers Ron and John, these are Cheers
Adrian


Top of pagePrevious messageNext messageBottom of page Link to this message  By Adrian Whiteman on Monday, January 26, 2009 - 11:55 pm:

"......these are very helpful",
Sorry about that!
Cheers
Adrian


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