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Old 06-01-09, 02:20 PM   #18
Baph
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Default Re: Why do my lights get brighter when I rev the engine?

Quote:
Originally Posted by thor View Post
Current is the voltage divided by the resistance of the system. It's not a tap. Given that reving doesn't reduce the load on the electrical system, then it must be due to an extra voltage being produced by the alternator. I guess the rectifier should be sorting that!
Current is actually a flow rate. Nothing more. Think about tidal currents etc. There's a reason they share the same descriptive name. With a tidal current, you have the same volume of water, moving at a different vector (direction and/or speed).

When the engine rev's higher, the alternator puts out a higher voltage, at a higher flow (current).

The regulator then ensures that this increased voltage is reduced to 12v (approx). The current generally isn't reduced by the regulator.

By upgrading bulbs (eg, Osram Nightbreakers as stated), the bulbs are designed to glow brighter. This is accomplished by drawing more current due to lowered resistance in the coil. If the alternator isn't putting out maximum current (for the bulbs) they will be dimmer than they can potentially be. When the current raises (by revving the engine), naturally the bulbs get brighter.

In my case, when I honk the horn, some of that flow (current) is diverted away from the bulbs to the horns. Thus making my bulbs dim. I also have uprated bulbs FWIW.

Further to this, my bulbs get brighter when I rev the engine (I'm talking only the first few thousand RPM, then it's constant). I have tested the rectifier, and alternator. Both are fine the last time I tested them (after approx a year running with this setup).
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