protecting DC components

miatawnt2b · 12-31-2020, 07:13 PM

Today one fo the kids headlights went out. Quick troubleshooting lead me to a bad LED headlight, and a bit deeper inspection led me to realize the voltage going to the headlights is AC on these quads. Tearing into the cheap LED headlight I found exactly what I suspected, a failed surface mount diode. Ideally the diode should be enough to protect the LED's and actually it did its job, but my guess is it's just a garbage component design and could really use some bridge rectification. Has anyone done electrical work on these things to further protect/harden the DC circuitry?

-J

TxTaoRider · 12-31-2020, 07:24 PM

The old Polaris quads used a small unit that you could probably make work? https://www.ebay.com/itm/VOLTAGE-REG....m46890.l49292

miatawnt2b · 01-03-2021, 05:51 PM

after looking at the schematic, what they did was energize both the rear running light and the headlights (labeled as daytime running lights) directly from the stator. This results in A/C current going to these components. This is fine actually when using standard bulbs, but LED's are quite a bit more sensitive to their forward/reverse voltage. The LED lights on my 125D are protected by diodes on the circuit board inside the light itself. However they are really tiny surface mount components and one of them had failed. I was able to replace it with pieces from the parts bin and my headlight is again working. I was unable to find any numbers on the SMD so i have no idea what it's rating it. My guess is marginal for the load.

Anyhow, back to the issue at hand. The LED's really need rectification at a minimum, regulation even better, and ideally a buck regulated supply. I'm going to opt for cheap and stick in a bridge rectifier between the stator and the LED running lights and see if that's enough to keep further failures at bay.

I could also rewire these to turn on with the key switch which is another option. The key being wired directly from the battery would utilize the stock regulator.

-J

miatawnt2b · 01-03-2021, 07:45 PM

Here is the schematic.

https://photos.app.goo.gl/Ex87eT9riiBQszWf6

I figured it was likely easier to use the stock DC regulation rather than add my own regulator as I needed to rip into the harness to fix the tail light and the headlights both anyhow

We'll focus on the yellow wire that runs between the stator, regulator, rear tail light, and daytime running lights (headlights). Between yellow and ground when the engine is running you get between 10-13 VAC. I took apart the wiring harness and found the connection of all of these yellow wires. I clipped the all 3 yellow wires going to the lights, and left the connection between the stator and the regulator.

Then I used a voltmeter to find what wires get power when the Ignition Key is in the ON position. The red wire is the feed from the battery through the fuse, and the black wire is energized with 12VDC when the key is on. so I traced this black wire into the harness and found a good spot to connect in the yellow wires to the lights.

A little soldering, tape and some zipties to put the harness back and my lights are now fed DC, and have the added benefit of coming on when the key is on. They also don't flicker like they used to at idle from the 'dirty' stator power.

splntrp · 01-29-2021, 03:18 PM

Just curious. How are these holding up since the change?

miatawnt2b · 01-29-2021, 03:29 PM

Holding up great. I did the mod to all three of my 125D's. No more issues with dim flashing lights.

12-31-2020, 07:13 PM	#1
miatawnt2b Join Date: Dec 2020 Posts: 78	protecting DC components Today one fo the kids headlights went out. Quick troubleshooting lead me to a bad LED headlight, and a bit deeper inspection led me to realize the voltage going to the headlights is AC on these quads. Tearing into the cheap LED headlight I found exactly what I suspected, a failed surface mount diode. Ideally the diode should be enough to protect the LED's and actually it did its job, but my guess is it's just a garbage component design and could really use some bridge rectification. Has anyone done electrical work on these things to further protect/harden the DC circuitry? -J
	0

12-31-2020, 07:24 PM	#2
TxTaoRider Join Date: Oct 2020 Location: Flower Mound Texas Posts: 904	The old Polaris quads used a small unit that you could probably make work? https://www.ebay.com/itm/VOLTAGE-REG....m46890.l49292 __________________ 2021 Tao Tbr7 - "Lucille" Mods so far- Brozz swingarm, 21" front rim (Bridgestone Tw302 rear/Dunlop D606 front tires), Digital gauge cluster, pz30b pumper carb, after market hand guards, aftermarket brake and clutch levers, round fold away mirrors, Fly handlebars shortened slightly, 13t front sprocket 2009 Q-link Legacy 250 1982 Suzuki GS1100ES - "Jolene"
	0

01-03-2021, 05:51 PM	#3
miatawnt2b Join Date: Dec 2020 Posts: 78	after looking at the schematic, what they did was energize both the rear running light and the headlights (labeled as daytime running lights) directly from the stator. This results in A/C current going to these components. This is fine actually when using standard bulbs, but LED's are quite a bit more sensitive to their forward/reverse voltage. The LED lights on my 125D are protected by diodes on the circuit board inside the light itself. However they are really tiny surface mount components and one of them had failed. I was able to replace it with pieces from the parts bin and my headlight is again working. I was unable to find any numbers on the SMD so i have no idea what it's rating it. My guess is marginal for the load. Anyhow, back to the issue at hand. The LED's really need rectification at a minimum, regulation even better, and ideally a buck regulated supply. I'm going to opt for cheap and stick in a bridge rectifier between the stator and the LED running lights and see if that's enough to keep further failures at bay. I could also rewire these to turn on with the key switch which is another option. The key being wired directly from the battery would utilize the stock regulator. -J Last edited by miatawnt2b; 01-03-2021 at 08:02 PM.
	0

01-03-2021, 07:45 PM	#4
miatawnt2b Join Date: Dec 2020 Posts: 78	Here is the schematic. https://photos.app.goo.gl/Ex87eT9riiBQszWf6 I figured it was likely easier to use the stock DC regulation rather than add my own regulator as I needed to rip into the harness to fix the tail light and the headlights both anyhow We'll focus on the yellow wire that runs between the stator, regulator, rear tail light, and daytime running lights (headlights). Between yellow and ground when the engine is running you get between 10-13 VAC. I took apart the wiring harness and found the connection of all of these yellow wires. I clipped the all 3 yellow wires going to the lights, and left the connection between the stator and the regulator. Then I used a voltmeter to find what wires get power when the Ignition Key is in the ON position. The red wire is the feed from the battery through the fuse, and the black wire is energized with 12VDC when the key is on. so I traced this black wire into the harness and found a good spot to connect in the yellow wires to the lights. A little soldering, tape and some zipties to put the harness back and my lights are now fed DC, and have the added benefit of coming on when the key is on. They also don't flicker like they used to at idle from the 'dirty' stator power.
	1

01-29-2021, 03:18 PM	#5
splntrp Join Date: Apr 2020 Posts: 7	Just curious. How are these holding up since the change?
	0

01-29-2021, 03:29 PM	#6
miatawnt2b Join Date: Dec 2020 Posts: 78	Holding up great. I did the mod to all three of my 125D's. No more issues with dim flashing lights.
	1