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Reducing inrush current to bulb filament.

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I was interested in finding out how one might reduce the current shock load on a light bulb filament. My initial thought was to just put an inductor in series to the light. My research says I can't do that and putting in an inductor in parallel does not result in what I am hoping to accomplish. I want to reduce the initial inrush current upon the filament when turning on a light and to slowly shut it off as well. The intent is to see if it will make the bulb filament last longer. I was only able to find video showing inductors in parallel. Nothing in series. Is anyone able to help?

I know its not directly EV related but if it works why not put it in the system to help increase the life of the head lights and other standard filament lights. I don't want to go to LED. I want to continue to use the standard filament bulbs in my Bug.

Pete :)
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· Administrator
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I would suggest a low ohms resister in series and a capacitor in parallel

The initial resistance is quite low - but when a headlamp bulb is hot it rises to about 4.5 ohms

If I'm reading this correctly it looks like a headlamp bulb will start with a resistance of 0.45 ohms - which will build up to 4.5 ohms when it's hot

So a 1 ohm resister will take 2/3rds of the initial surge and only 20% of the voltage when hot

Or a 0.45 ohm resister will take half of the initial surge and only 10% of the voltage - which will also contribute to the life of the filament but at the cost of some brightness
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