Voltage regulator

My 1980 tomos bullet is stock 6v system. Since putting a kit on it, have been blowing bulbs. I bought this voltage regulator from treatland.

https://www.treatland.tv/trail-tech-voltage-regulator-p/trail-tech-regulator-7003-ac01.htm

It says use on 6v or 12v system in post, however when manual comes in box it says that it regulates voltage between 12v and 16v. How is it then compatible w/ 6v system as advertised on treatland? Will the 6v bulbs that are stock in the bike handle that 12v regulator? Do I need to change bulbs I'm using?

Re: Voltage regulator

Change your bulbs. That will not regulate down to 6v.

Re: Voltage regulator

Brad William /

I'm just going to post a few guesses here but it'd be nice if someone more skilled would weigh in.

Your stock light coil produces 6v "nominally". It's only a suggested number since, unregulated, it probably ranges from about 3vac to 18vac on a fairly straight voltage/rpm curve from idle to max rpm. That's why it's 3v dim at idle and 18v bright when top speed. You kitted it and raised peak rpm enough to push that coils top over the 20v point and the bulb finally reached it's limit.

So let's say your coil, at low rpm, is putting out 3 to 6vac. No problem so far. But if you put a 12vac regulator on it it's probably not going to kick out any voltage at all, no light, until you're at medium rpm at feed the regulator something it's at all happy with.

If you put a 6v regulator on it, it'll probably )still guessing here), kick in the lightbulb at a lower rpm, but limit it at some point below the max you've been used to, unregulated, at peak rpm.

In order not to have any of these tradeoffs, you'd have to replace the 6vac coil with a 12vac version and run the 12vac regulator. Then the coil is producing enough juice to meet the lowest demands of the regulator at idle, and light the light, as well as deliver the 12-16vac to the bulb that your new kit is delivering, but the 12v regulator will protect the bulb from the 20+ (probably waay plus) vac that your new 12vac coil is pumping out of your new screaming kit.

I have no fucking idea what I'm talking about here. I've never measured any of this. Just hunches based on quite a bit of trial and error and rudimentary background in electronics.(edited)

Re: Voltage regulator

Just run the regulator, don't fuck with the coil. Change your bulbs.

Re: Voltage regulator

Brad William /

Shorter version, I think the regulator you have will be fine. But without changing the coil to a 12v version, you may not get any light at all until you're at medium rpms. The six volt coil just doesn't put out enough voltage for the lower threshold of the 12v regulator until the flywheels really spinning.

Re: Voltage regulator

Brad William /

...or does it? I'd be interested to know.

Re: Voltage regulator

Up the voltage to 12, but keep wattage or bulb the same??

Re: Voltage regulator

V x A = W

25w/12v 2.08A

25w/6v 4.16A

12v bulbs will not draw more power from the stator. The only thing that would keep voltage low at lower rpm is that the 6v coil will have less turns (voltage) in it and may have thicker wire (amperage). It will without question power 12v bulbs of equal wattage. If you are concerned with low rpm output run an led tail.

Re: Voltage regulator

Less concerned with low rpm brightness, more concerned about bulb life. I'm assuming it's safe to say the 12v bulb will hold up a little better, especially with this regulator. Will give it a shot, thanks!

My other question, if you look at this wiring diagram...

https://www.mopedarmy.com/w/images/d/d9/1980_A3_wiring_colored.JPG

I obviously need to tie the voltage regulator into my yellow line which goes up to horn, headlight, and back to tail light. Brake light however is off a separate coil wire, separate line. Does this need to be accounted for somehow with regulator? Only reason I'm paying such close attention to this is that I know the resistor is tied into brake light in this system and if that bulb goes it throws the whole system off.

Re: Voltage regulator

I run this with 6v bulbs. No problems. Haven’t blown a bulb. But running 12v bulbs brings convenience of any auto parts having the bulb you need.

https://www.treatland.tv/yamaha-FS1-6V-regulator-p/yamaha-fs1-6v-regulator.htm

Re: Voltage regulator

If it throws the whole system off then it is a tap off of the same lighting coil and does not need to be regulated separately.

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