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Is it possible to correct reversed polarity in scooter lighting

Is there a way to reverse the polarity to the light bulbs without 'blowing up' the system? I wish to use regular LED light bulbs.

I have this generic Chinese scooter with 48v 500 watt controller with 3 speed and reverse, no cruise control. There is a dc/dc converter similar to your 36-72 Volt DC to 12 Volt DC 10A Converter.

I wanted to replace incandescent bulbs with LED bulbs. When LED bulbs didn't light, I found that the polarity was reversed. I would have switched wires to the socket, but is impossible with dual filament bulbs. 

I purchased bulbs with circuitry to handle reverse polarity, and it worked. I am using these bulbs in the dual intensity head lamp, and the brake/tail lights. 

I have found that these special LED bulbs are affecting the system in weird ways: 1) When riding at night, and I squeeze the brake several times rapidly, a signal is sent to the controller to stop the motor! A simple on/off of the main power switch restores power to the motor. 2) I wanted to add a brake light for safety, like in cars. I tapped into the brake wire at one of the tail light sockets, which seemed to work until I turned on the running lights, which also lit the new brake light. I attached a volt meter to my new brake light wire, and there is 12v when the brake lever is pulled, but if I turn the running lights on, 9.5v is detected! This same weird reaction happened when I switched the wire to the tail light.

I am not sure why the LED bulbs are affecting the electrical system in weird ways. It sounds like the scooter may be detecting when a bulb is burned out and shutting down the motor, and the LED bulbs have such a low current draw that the scooter thinks the bulb is blown out. This is just speculation though and I am not sure exactly why that is happening.


If the non polarity bulbs are removed (no bulbs) or replaced with the original incandescent bulbs, the voltages are correct: 12v is detected on the brake wire only when the brake is pulled, and 12v is detected on the tail light wire only when the lights are switched on. I am just pointing out my findings of the use of non-polarity LED bulbs. 

It was not my intention to focus on the adverse effects of non-polarity LED bulbs. 

The standard polarity, adhered to in most vehicle lighting today, is a positive charge applied to the contacts at the bottom of a bulb, and the negative, or common, wire applied to the outside casing of the bulb. Imagine this while looking at a 1157 type bulb. My situation is opposite from this standard.

The question I ask is: Can I safely modify the wiring to match the standard polarity for the lights without harming the controller?

I am not very familiar with controllers, and my knowledge of electronics is not too technical. I have looked at the wiring diagrams you list with your controllers, and there is no mention of lighting. 

Most electric scooters do not have a negative ground to the frame or body like cars do. So you should be OK with reversing polarity to the bulb holders. I would verify that you scooter does not have a negative ground before doing so though. You could verify by setting your multimeter to DC Volts and touching the positive multimeter test lead to a positive battery terminal and touching the negative multimeter test lead to a part of the scooters frame that conducts electricity. That will indicate whether the frame is grounded or not.

When reversing polarity to the bulb holder I would also check for continuity on the second connection before actually connecting it, to make sure that there is no continuity when reversing polarity that is caused by something else. That way you could be 100% certain that you will not harm anything by reversing polarity to the bulb holder.

Please let me know if I missed a question, or if you have any further questions.

l have still not found a solution to the reversed  polarity observed at the sockets of the scooters 12v lighting system, but this problem is still bugging me to no end. My lack of electronic knowledge and physical disability have been keeping me from digging deep into the wiring of the system. l have failed at all attempts to obtain help or a wiring diagram from the retailer, distributor or the Chinese manufacturer.

l finally took a chance and switched the positive and negative leads exiting the 48v to 12v converter. This worked spectacularly for all light sockets including high/low headlamp and running/brake lights, using LED bulbs in place of incandescent bulbs. The only problem was with turn signals not blinking. Turn signal bulbs were not replaced with LEDs.

The problem with reversed polarity is mostly solved! ...Not quite!

l tried to ride the scooter with the full compliment of bright LED lights only to find that there was no power to the motor.

lt was not apparent to me that output from the 12v converter would affect the rest of the system. l unplugged the 12v converter and power was restored to the motor.

Can anyone provide me with insight into what might be happening?

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