High Output Charging System

I'M BACK! And still trying to deal with my charging system woes.
Have a 77 KZ-650 with Dyna ignition. About a year ago, I lost a phase on my stator, and regulator. Matched two good stator windings to two good reg. inputs, but cant run bike with lights
on. . . not enough output voltage. Somebody suggested the alternaor wasn't powerful enough to handle the Dyna as well as the basic electrics. Since the stator needs rewound anyway, is it feasible to wind with thicker guage mag wire to handle more current, or does the field winding need more turns? How can I distinguish alternator capability? I'm gonna try attaching a picture of my stator. Thanks guys and gals,
RICK

Has anyone else had issues with Dyna-S, the coils you're running, and the stock alternator setup? Seems unlikely to me, but I've never had that combo, either.

Ask these websites:


Stators, Regulators & Rectifiers

www.rmstator.com
www.electrosport.com
www.customrewind.com
www.regulatorrectifier.com
www.ricksmotorsportselectrics.com
www.oregonmotorcycleparts.com

Assuming 14 volts,
The stock ignition uses about 3.5 amps. (About 50 watts)
The Dyna S with 3 ohm coils will use about 9.3 amps. (About 130 watts).

That's like adding an 80 watt spot light.

That's a whopping difference. It will really show up at idle speeds where the alternator is not putting out much power. I think the alternators can put out somewhere around 200 watts, but that won't be at idle.

The reason is because the Dyna S nearly doubles the dwell time. This plus the fact that a 3 ohm coil, alone, uses 25% more current than a 4 ohm.

Unfotunately, at lower RPMs, all of this extra power is only dissipated as heat in the coils. None of the extra is put into spark energy because the coils can only store a certain amount. The rest turns into heat in the coil. At higher RPMs, a percentage of the extra power will in fact go into longer spark duration. (The actual amount depends how high the RPMs are, and the coil's inductance etc.)


Because the 77 kz650 is a one-year only alternator, I don't think I've heard of a heavy duty stator available.

BINJIEU wrote:

I'M BACK! And still trying to deal with my charging system woes.
Have a 77 KZ-650 with Dyna ignition. About a year ago, I lost a phase on my stator, and regulator. Matched two good stator windings to two good reg. inputs, but cant run bike with lights
on. . . not enough output voltage. Somebody suggested the alternaor wasn't powerful enough to handle the Dyna as well as the basic electrics. Since the stator needs rewound anyway, is it feasible to wind with thicker guage mag wire to handle more current, or does the field winding need more turns? How can I distinguish alternator capability? I'm gonna try attaching a picture of my stator. Thanks guys and gals,
RICK

In general: increasing output of an AC generator requires thicker wire, more turns, and probably more core material because of the increased flux density. All of the above equate to larger physical size.

loudhvx wrote:

Assuming 14 volts,
The stock ignition uses about 3.5 amps. (About 50 watts)
The Dyna S with 3 ohm coils will use about 9.3 amps. (About 130 watts).

That's like adding an 80 watt spot light.

That's a whopping difference. It will really show up at idle speeds where the alternator is not putting out much power. I think the alternators can put out somewhere around 200 watts, but that won't be at idle.

The reason is because the Dyna S nearly doubles the dwell time. This plus the fact that a 3 ohm coil, alone, uses 25% more current than a 4 ohm.

Unfotunately, at lower RPMs, all of this extra power is only dissipated as heat in the coils. None of the extra is put into spark energy because the coils can only store a certain amount. The rest turns into heat in the coil. At higher RPMs, a percentage of the extra power will in fact go into longer spark duration. (The actual amount depends how high the RPMs are, and the coil's inductance etc.)


Because the 77 kz650 is a one-year only alternator, I don't think I've heard of a heavy duty stator available.

Makes sense...but I'm still curious if anyone else has the same setup with the stock alternator and has/hasn't had the same issue.

I ran a Dyna S for several years on my 77 650 with the stock alternator (3-phase excited field), had no problems what so ever.

In my experience with the excited-field alternators, (mostly on KZ400's but a 650 also) they can produce a little bit more current at low RPMs. But even with the permanent magnet, if everything is in good shape, the Dyna S should work fine.

It will basically come down to how much idle time you have compared to 2000 RPM and above. In Chicago traffic, if you only go a couple miles at a time, half of the travel time can be at idle. Even the stock ignition may have you using a battery tender every month or so to top off. That's with kick start. Electric start may have you topping off every week if you ride every day.