It appears you have AC powered lights because they only light when the engine is turning. LED lights are still possible, but not without some rewiring. We need to get your charging system working first.

To answer some of your questions first:

On your battery, small or big is not relevant. A small good fully charged 5 amp hour can crank your quad starter for 10 minutes before going dead. A much larger 10 amp hour battery can crank your starter at the same speed and power for 20 minutes. So what? If is doesn't start in ten seconds then you've got other major issues. Small batteries are fine. There is no advantage to a bigger battery. So while you're figuring out those other issues just jump your quad battery to your car battery (get the polarity right!) and now the battery capacity is out of the picture while you deal with other problems.

Note: Don't crank your starter for more then 1 minute without allowing it to cool for ten minutes. Don't burn up your starter motor... It is designed for short term use only.

To check the charging system: Start up the quad, and run the engine at 3000 RPM (roughly - say medium fast speed) with the headlights off. Measure the DC voltage with a meter right on the battery terminals. You should read 13.5 to 14.5 volts. If you do then the battery charging system s working. If you measure more than that then the battery is being over charged, if you measure under that the battery is being undercharged. Both of those scenarios will wreck the battery quickly.

You need to have a good battery charging system before advancing to putting LED lights on your quad.

 

Lynn,

I finally had a chance to test the electrical - not running the battery is about 12.6V - then running it jumps up to about 13.9V at mid to high RPM. So appears to be charging OK. So I tested it at the headlight socket and at idle its sending about 1.5V (why they are dim or not lit) and as you rev it it increases... But at high rpm it is at 14.1V... Can the lights take this or is that too high? I am thinking it should be fine and that the filaments are just vibrating apart when the get bright hot, not over voltage.... What do you think?

 

It looks like your battery charging system is working fine .

Your lights are definately AC powered, so I'm wondering how you're measuring the voltage on the lights. Are you measuring AC volts or DC volts? It is also more complicated than that. The voltage regulator has a DC regulator side that feeds the battery charging circuitry, and an AC voltage regulator that feeds the lights. The AC regulator circuitry produces a really strange waveform that has both DC and AC components. That's going to foul your meter measurement up completely. Measuring the true voltage of a strange waveform is difficult, but if the meter manufacturers assume that an AC waveform is a pure sine wave (the waveform you get from the power company) then it is easy - just scale the peak voltage by the square root of two divided by two. But for any other waveform your meter will give erroneous results on the DC and/or AC scales.

In case you're curious here is a schematic of a 4 pin regulator that I took apart and traced out a year or so ago (it has both the AC and DC regulator circuitries):



This is probably way over kill, and too much information, so let's get back to the problem of lights that burn up. If your AC powered lights still burn up at high engine RPM then it's got to be a faulty voltage regulator. The AC regulator side isn't working and allowing the voltage to go too high.

Caution: There are so many 4 pin regulators out there that look indentical, and are completely different and not compatible with each other. So I would go directly to your quad manufacturer to buy relacement parts (assuming you know your quad manufacturer, and they're still in business).

 

Wow - Lynn, that's technical, but helpful! I was just running the voltmeter with the ground to the edge of the bulb socket (no bulb in socket) and then touched the positive lead to the terminal in the socket... I guess the question is - can the headlight bulb take 14.1 volts or will that blow it? these bulbs are from the Chinese quad manufacture and are probably low quality - so I question whether a better bulb or an aftermarket light kit would be the way to go. I guess the simple test for me as a rookie would be to just wire another light to one of the bulb socket wires and see if that blows. I can get a 3" 12V 55w farm machinery spotlight for about $3 at Pricess Auto... May be a cheap investment to test the system - your thoughts?

 

14.1 volts is normal operating voltage. Remember that even on DC powered lights the battery voltage is raised to 14 volts by the battery charging system. And that means the lights are running on 14 volts too.

But the question remains is whether your meter is telling you the truth since the waveform it is measuring is far from being a sine wave.

My 150cc GY6 engine with an upgraded 8 pole stator will only put ut 55 watts of power at a fast engine speed. So your 125cc is not likely going to drive a 55 watt spot light. If your lights were DC powered then the excess power would simply come from the battery (which would be draining it as you ride instead of charging it). But on AC powered lights there is no reserve power source, and so the light would just always be glowing dimly - even at high engine speeds.

 

THis is an old thread, but I gotta ask... the LED DRL lights in question state 12/24v... and they are LED. So what's the problem with running them on AC? LEDs by nature are rectifiers and would run only on 1/2 of the AC cycle. If you see the flicker, then a full wave bridge would do the trick. FOr example, radio shack part number 276-1185

You just need to use 1/4" spade connectors to connect the alternator output to ac pins and the lights to the + and - pins. Easy peasy!

 

I had the same problem with atv. Had to add a ground wire from the negative on the light to the frame. Problem fixed.. I have even added more lights and it's still fine. They run off the motor. I.e stator