50W 6Amp Alternator for Bicycles that WORKS!

[Deleted Member 4613]

OK, good, I wasn't sure if the generator produces AC or DC. Did you get your answer on the reg/rec? 4 pin or 5 pin? Mike Go for it!!

 

[Flattracker]

You said you are using off the shelf components?

Yeah, I used store bought components. However there is a problem with their durability.

I had to replace my scooter rectifier/regulator because it couldn't handle the power. In short it failed. It would have helped if I had the regulator/rectifiers specs available before the build, but its not a problem. Not the alternator, but the regulator. The alternator is too powerful for it to handle.

I started to just buy a motorcycle rectifier/regulator but had already bought the bridge rectifier, and decided to use it instead.

So I replaced the scooter regulator with a 40 amp full wave bridge rectifier to convert the AC current to useable the DC form.

I'm ordering a 200 watt universal snowmobile type voltage regulator for the battery charge regulation.

I'll wire it inline on the + DC output of the rectifier.

That ought to be able to handle the power output. On testing, the bridge rectifier just barely got warm.

The scooter regulator I was using was just like yours.
On my 4 pin regulator the AC inputs are diagonal from each other. One being in one corner, the other located diagonally in the opposite corner. The Positive and negative outputs are the other two pins. A test light or multi meter works here.

 

[HseLoMein]

Thanks Flat, i just friend mine while testing. I have 2 more coming doubt they will be able to handle the load. I wonder if using a motorcycle regulator/rectifier would work. the one in my bike is large and i know my stator puts out 170 watts so hopefully it can handle the load. Unfortunately because i is a 3 phase regulator it wont be as efficient. if not i will go for a separate regulator. Another option i was thinking is to wire multiple small regulators in parallel. maybe they wont burn out as fast.

 

[AussieSteve]

Finally got my new computer and uploaded some pics of the headlight/battery setup, in the '... Headlight Wanted' thread:-
Pics of mounted headlight
Gonna fit a horn, then I'll get back onto the generator / regulator.

 

[Deleted Member 4613]

Flattrack, I think you're on the wrong track by buying separate rectifier and voltage regulator, which is going to increase cost. Can you find a rectifier/reg in one part that will do the job? The original idea was great because the 4 pin rec/reg is only about $18.Ms

 

[Flattracker]

buying separate rectifier and voltage regulator,

Yeah, I know. I really wanted one single rectifier/regulator unit for a few reasons.

Space needed to mount things, second is cost, third simplicity in building. I 'm just doing it the lazy way, and motorcycle electronics are expensive!

Still, if I wasn't so lazy about it I could research what model motorcycle reg/rectifier unit operates under similar output as the alternator.

I guess these little alternators will put out at least 10 amps, but I'm only guessing.

Again, too lazy to perform a complete test on the alternator. I've only tested AC, and DC voltage output.

My 40 amp bridge rectifier with an electorlytic filter capacitor across the +-DC outputs will handle it. If needed, another capacitor and inductor can be added to the circuit to virtually eliminate any voltage ripple and provide a stable DC current.

Later on when I get bored I'll eventually locate a compatable unit.

I really hate to use a separate regulator and rectifier, but from what I've seen in rectifier/regulator costs, its cheaper this way.

 

[Flattracker]

Homemade rectifier circuit w/filter on the Alternator

Well the revamped charging system is finally finished. These lights are BRIGHT! I've traveled 100 miles so far running my new lighting system. The RC truck tire(s) around the alternator wears fast. Glad I bought a 4pc set. Nothing has vibrated loose, or fallen off (except the horn that I forgot to tighten).

The engine is still being broken in and I haven't traveled more than 10 miles at a time or been beyond 25 mph yet.

The batteries charge really well with no regulator at these speeds, and distances, but I'm buying a universal 12v regulator anyway to prevent excess current.

I'm very pleased with my system, and wont be having any more lighting deficiencies. I can even add those LED accent lights to light up my engine! All my power needs have been met!

I don't think there's a better method to power a bicycle electrical system. Good luck to you all!

 

[AussieSteve]

The batteries charge really well with no regulator at these speeds, and distances, but I'm buying a universal 12v regulator anyway to prevent excess current.

What voltage are the batteries charging to with no regulator?
Beware of over-charging.

 

[Flattracker]

What voltage are the batteries charging to with no regulator?

Its on the high side. I tested 25 volts AC with my DMM at about 300 to 600 wheel RPM.

Lets see, minus the 6.8 volts the diodes in the bridge rectifier consumes, I guess I'm somewhere in the neighborhood of 18.2 volts DC.

I could break the voltage down more with the addition of a couple LEDs, and limit the current with a power resistor, but like I said before, my town is so small if that if I ride 10 miles around town I've been through it 3 times.

I turn on my headlight for now, like the truckers used to do in the old days to soak up some of that power and to prevent overcharge. Its a safety feature, yeah that's the ticket!

I don't ride it enough to over charge the batteries. I'm limiting my riding until I get a proper regulator. Most of the items I've been using I've bought previously and were sitting around unused. When I can afford better quality I'll get better quality

 

[AussieSteve]

The headlight will help pull the voltage down.
My plan is to always run the headlight anyway. Much safer, from a visibility point-of-view, particularly on cloudy/overcast days.

Most modern motorcycles have a single rectifier/regulator unit, I think. Have you tried a motorcycle wreckers?