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Old 01-03-2013, 03:48 PM   #77
craftycoder OP
Motobrain PDU
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Joined: Oct 2009
Location: Atlanta
Oddometer: 2,332
I am familiar with the idea of constant current. I guess I just fundamentally disagree with the common knowledge. The definition of a constant current is a constant voltage through a constant resistance. Therefore, using a resistor to limit the current is no more inefficient than using a constant current supply as the resistor doesn't use extra current, it just limits it which is all the active constant current circuit is doing. What it DOES do is require you to set the resistor to a conservative value or risk blowing the semiconductor during transients. This actually means that on average you should use less power with a resistor compared to a constant current supply. The cost of this will be the max brightness you can attain.

So, if the complaint was that you need all the light possible and a resistor leads to LEDs being too dim, I'd buy it. Efficiency, I am not buying. Personally, I don't worry about maximum brightness. I'm putting on the aux lights because my main light is a giant steel grill in front of it to protect it from flying rocks and its covered with mud so I can't see the damn road until the next river crossing. If I was really concerned about max brightness I'd not ride in the mud.

My system does NOT boost the voltage so you will have to concern yourself with forward voltage drop if you have too many LEDS in series. I also doesn't do any voltage regulation (short of cutting out transients above 18V). My system therefore would not allow you to get "maximum" life span and "maximum" brightness out of your LEDs but they are still going to be damn bright and you will be able to control them from your phone from the campfire when you want to see what just flew into your can of Dinty Moore stew.

This will all be irrelevant if I can get a fast enough data feed from my current sensors to create an active constant current supply. If I can, I'll short out some wires on video and post it up for all to see. Then, I'll send you a virtual beer for the fine idea.
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