# HELP!!! adding a magneto (belt driven)



## jwmatt (Jan 25, 2021)

Hi everyone, this is a great site. Had a single stag for three seasons and got a two stag recently. It is turning out to be a toy for me. It's a MTD Yardmachines 5/22. Great running machine in like new condition. Added a magneto (belt driven}. It doesn't have a internal regulator. It puts out dc 12v, 20 amp, 240 watts. what do I need from that point? Would like to power up heated hand grips, dc 12v, 2.5 amps, 30 watts and led lighting, dc 12v, 3.4 amps, 40 watts. Can anyone help?


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## Johnny G1 (Jan 28, 2020)

You are going to need a battery of some sort as an alternator won't work without one. Then hook all to the battery and switch's. what is powering the alternator, a belt off the engine or?????


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## db130 (Feb 16, 2013)

Could we see some pictures of this alternator that puts out 20 amps?


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## RIT333 (Feb 6, 2014)

I have never had a battery on any of my small engines, and they run lights and heated hand grips.


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## ChrisJ (Nov 27, 2014)

An alternator can self excite under the right conditions but they typically have a battery to get them going.

All of the small engines I've had used magnetos to power headlights etc.

People may use the names interchangeably but they're very different. A magneto uses permanent magnets an alternator does not.


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## jwmatt (Jan 25, 2021)

Johnny G1 said:


> You are going to need a battery of some sort as an alternator won't work without one. Then hook all to the battery and switch's. what is powering the alternator, a belt off the engine or?????





ChrisJ said:


> An alternator can self excite under the right conditions but they typically have a battery to get them going.
> 
> All of the small engines I've had used magnetos to power headlights etc.
> 
> People may use the names interchangeably but they're very different. A magneto uses permanent magnets an alternator does not.


Hi Chris, your right. It really is a magneto. Listed and sold as a alternator. My mistake. I will redo the discussion topic. Just in the design stag. So far, I believe it's going to work. Will post updates with pic as things progress. Thanks for the heads up.


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## drmerdp (Feb 9, 2014)

I believe stator would be a better term. 20 amps... sounds A little funny... Definitely needs some pics or a part number to check it out. Is this a tecumseh engine?


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## jwmatt (Jan 25, 2021)

Hi, I am mounting a magneto (belt driven) to a 5hp Tecumseh. The magneto is used on several small engine type equipment. It is listed as producing 12v dc at 20 amps. This where I need help in design the electrical system.


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## drmerdp (Feb 9, 2014)

Oh wow, actually belt driven, sounds like fun. Magnetos use permanent magnets, alternators induce a magnetic field. If it’s internally rectified to DC you’ll need a battery In the system.


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## jwmatt (Jan 25, 2021)

Hi, this has been a leaning experience. AJ electric has been a big help. The magneto actual puts up a.c. current. Need to add a rectifier. Got a few more things to check out. It's time to order the magneto and get it mounted. Get a meter on it and then figure out a rectifier.


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## ChrisJ (Nov 27, 2014)

What are you using the magneto for?
That would determine what kind of circuit you'll need for it.

Incandescent lights work fine on AC. For LEDs I'd personally want some good filtering to get rid of any flickering.


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## jwmatt (Jan 25, 2021)

The plan is to install some led lighting and hand warming grips. First step - get the magneto mounted and up and running. Then figure the rectifier.


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## jwmatt (Jan 25, 2021)

ChrisJ said:


> What are you using the magneto for?
> That would determine what kind of circuit you'll need for it.
> 
> Incandescent lights work fine on AC. For LEDs I'd personally want some good filtering to get rid of any flickering.


Hi Chris, plan to run two 20 watt led, a group of hand warmers at 45 watts, a second group of hand warmers at 30 watts.
Also considering a cell phone charger, beverage warmer and fm stereo.....just kidding.


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