I want to add a battery/magneto starting option to my magneto. Any help with wiring diagram would be helpful
Not sure what you're asking...
"I want to add a battery/magneto, (DU4??), starting option to my magneto, (DU4??)."
Your options, as I see them, are:
1. Traditional: battery/coils OR Model T magneto.
2. DU4 only.
3. DU4D, (a Bosch dual magneto that can be self energized like any traditional magneto OR externally energized by a battery, making it essentially a distributor)
Bosch DU4D mags are hard to find and hard to pay for.
I think he may be talking about this. Here is how Maxwell did it. Maxwell used a Simms SUD4 Magneto.
The reason for this was the lack of impulse drive. Slow Rpm with the battery option allowed the mag to fire.
That's either how a DU4D works, or how a low tension magneto works. An example of the low tension Mag would be the Splitdorf Model O, as used in early Overlands.
Oh, I see you mentioned it's an SUD4. Not familiar with Simms but I'll bet the "D" is for dual.
FWIW The transformer coil shown at left in Mike's diagram is also called a choking coil and measures 1.2 ohms resistance. The Maxwell coils are hard to find. If you use this setup it might be worth knowing.
Jerry, Simms built magnetos under Bosch license.
Simms-Bosch magneto 1903
In conjunction with Robert Bosch he invented developed and patented the Simms-Bosch ignition magneto. It enabled engine designers to precisely time the ignition of fuel because it was tied to the rotation of the engine. Their initial low-tension system was not an unqualified success but they became the first to develop a practical high-tension magneto. In 1899 they established the jointly owned Compagnie des Magnetos Simms-Bosch but it foundered in 1906 on personal differences between the partners. In 1907 Simms established the Simms Magneto Company Ltd to manufacture magnetos under licence from Robert Bosch but he was unable to compete with European prices and it closed in 1913. He had however contributed to Bosch's business by his stimulus to their further product development and in opening up the French market for Bosch.
I have one of the Simms magnetos like that for sale, will start on battery and run as a magneto $400.
I hooked up a Simms mag and used a T coil primary as the "transformer coil", and it worked fine.
For a small engine like a T, the Bosch DU4 without impulse will start and run the car easily. On larger displacement cars, it's hard to crank the engine fast enough for a good spark, thus the impulse drive was added. The DU4 on my '10 Hupmobile provides a very hot spark at fairly low rpm.