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Old 02-09-2012, 11:18 PM   #1
kitjv
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Question ? How to Wire a Voltage Regulator ?

I'm restoring a '73 Hodaka Wombat Model 94A from scratch. I am in he process of building a wiring harness. The bike has a 6V electrical system with headlight, taillight, turn signals & instrument lights. Interestingly, the wiring schematic does not show a voltage regulator. But common sense suggests to include one.

Electrical systems are not my strong suit. So ... can someone suggest where in the circuit a voltage regulator should be spliced? My limited knowledge suggests to place it just downstream from the battery & the main fuse. But I would prefer the opinion of someone more knowledgeable than I. Thank you.
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Old 02-10-2012, 12:02 AM   #2
WintrSol
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Normally, a regulator would go between the alternator/generator and the battery. Most bikes use a fixed-magnet system, generating AC current from a stator, so have a rectifier to convert that to DC to charge the battery. The regulator measures the battery voltage, and limits the current to it when it reaches full charge. It may very well be that your bike didn't come with one, as the lights draw most of the power from the stator, so the battery doesn't overcharge. If it did have a regulator, it probably worked like the one on my '70 CB450: it had one connection to the battery, one to ground, and a third to the stator output, before the rectifier. It works by shorting the stator to ground when the full charge voltage is reached.
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Old 02-10-2012, 10:23 AM   #3
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WintrSol,

Thank you for the response. I agree with your description of how the electrical system works on this bike. However, I was a bit remiss when I said that there was no voltage regulator on this bike. Apparently, this bike was retro-fitted at the factory with a "current limiter" to address the problem of blowing headlight bulbs due to excess voltage at higher rpms. When restoring these old Hodakas, it is my understanding that most guys will replace the so-called current limiter was a good 6V regulator.

On the factory wiring schematic, the current limiter (or replacement regulator) is located downstream from the key switch. That suggests to me that you are correct in saying that the regulator is normally located between the alternator & the battery.

Thus, I would assume that in this location the regulator would not only protect the battery from excessive charging, but would also similarly protect the lights as well. Does this sound reasonable?

Thank you kindly for your help. I appreciate it.
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Old 02-10-2012, 08:11 PM   #4
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So, there was a limiter to keep the lamps from burning out, but the battery voltage was unregulated? Seems like a problem to me, as excess charge voltage to the battery would boil the water out and cook a battery.

I don't know of a to source buy one, but a linear pass regulator is what I'd build. I have one on my CB450 (12V) now, replacing the one I described. I bought it from someone in Oregon; there's a bigger market for 12V systems, though. If you have a friend who is an electronics experimenter, regulators are fairly easy to design and build, it's the packaging which is the most trouble.

Basically, you would have:
AC from stator --> rectifier --> regulator --> battery --> key switch --> feedback to regulator, lights, everything else.

With this arrangement, the battery voltage is controlled at about 7.4V, protecting your battery, and your lights won't burn too brightly.
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Old 02-10-2012, 09:57 PM   #5
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If I am correct, by placing the so-called current limiter downstream from the key switch, both the lights & the battery would be protected from voltage spikes. However, as I understand it, the current limiter was a retro-fit after Hodaka received complaints of blown headlights. Seems odd that this problem wasn't addressed initially on the drawing table. But, apparently the issue of boiling batteries never surfaced.

Anyway ... I obtained a 6V voltage regulator from a purveyor of Hodaka parts in Vermont. So I should be good to go.
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Old 09-09-2012, 06:24 AM   #6
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The regulator should be placed just after the rectifier.. so first the magneto..rectifier...regulator and then the battery

regards
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