Do i need to buy a ballast resistor ?

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Deion Adel
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Do i need to buy a ballast resistor ?

Post by Deion Adel »

Need help! The led lights on my headlight begin to flicker after I replace the headlight. My friends told me that I need a resistor as the voltage in an led circuits beyond. I checked that theballast resistor has the function of limiting the voltage? Do I need to purchase it? Please share your idea.
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dacflyer
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Re: Do i need to buy a ballast resistor ?

Post by dacflyer »

we need more info on this to be able to give you a good answer...
dyarker
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Re: Do i need to buy a ballast resistor ?

Post by dyarker »

Info like did you replace a nonLED type headlight with an LED headlight?

The purpose of resistor in series with LEDs is to limit current. Of coarse current through a resistor will cause a voltage across the resistor.

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Dale Y
dyarker
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Re: Do i need to buy a ballast resistor ?

Post by dyarker »

An alternate reason for resistor -

From google.com
Headlight LED load resistors prevent "bulb out" error messages and bulb flickering. These 6 ohm 50-watt load resistors compensate for the low power draw of 9005 LED bulbs so that they can communicate properly with your vehicle's computer system.
If you replaced a type headlight that used more current, then you may need load resistors in parallel with bulbs (not ballast).

Cheers,
Dale Y
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dacflyer
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Re: Do i need to buy a ballast resistor ?

Post by dacflyer »

So what's the point of updating the lights, if it isn't going to save you any power load... the resistor seems to defeat any power saving..
dyarker
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Re: Do i need to buy a ballast resistor ?

Post by dyarker »

A. 50 Ohm resistor will draw about 600mA. Wouldn't that plus LED still be less current than incandescent or quartz?

B. I wouldn't make the change myself. A car that comes with LED headlights won't need a resistor to "fool" the car computer.

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Dale Y
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haklesup
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Re: Do i need to buy a ballast resistor ?

Post by haklesup »

I've only had to add load resistors to the turn signals because the flasher relay requires a minimum current to run. That resulted in variable flash rates under different load situations so I found a solid state flasher relay and replaced that in my fuse box and now it works with or without the ballast (though I didn't bother to remove them) at a consistent flash rate.

Note that careless installation allowed one resistor to partially melt the insulation from a nearby wire, they do waste a lot of watts.

For headlights, you should not need a load or ballast resistor, something else is going on. I found that some LED lights especially from eBay are defective and did not attach the LED properly to the heat sinking structure and they either burned out prematurely or intermittently stopped working for a while (blinking).

I did manage to get a reliable LED for my headlight but it is very bright and maybe 6500K bluish, probably exceeds DOT regulations, It also does not focus properly for high and low beam since the lamp is in the wrong position for the reflector designed for a 2 filament bulb. It might have worked better if mounted 180 degrees in the housing but the mount does not allow that. It almost seems like high and low beams are flipped but high beam barely makes a difference they are already so bright. That vehicle rarely gets used at night anymore.

My advice is if you want to convert to LED headlights properly, don't just replace the bulb but go get a properly fitting lens housing replacement kit with LED lamps so It focuses on the road appropriately and you don't blind other drivers.

I plan to look at these updates in about a year, since I did the upgrade a few years ago, many new options have appeared.

Keep in mind that for interior lights, you may want to add a current source (usually a buck boost regulator set in CC mode) because the 12V supply in a car can range from 11.5 to 14.5 depending on if the car is running or charging or parked and partially depleted. This results in brightness variation in LED with direct 12V connection.
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