Omigod, ya'll! I put the red 54 LED truck brake/turn/tail light on my second commuter yesterday. You cannot even imagine how bright this thing is. You DEFINITELY don't want to be right behind me on a bike. You tires might melt...right after your retinas! On the bright setting, as I now have it hooked up, it draws just over .6 amp. I plan to install a two-way switch so I can switch settings. The lower taillight setting is less obnoxious.
I called Maxxima, the company that makes the white 54 LED back up light. They said they didn't think it would project the light. Let me tell you, this red brake light definitely project light. It it is any indication I think the white light might be equivalent to at least a 10W halogen and probably more, maybe even 20. I am going to do some experimentation and may give one a shot after all. There is a site that has LED replacements for common bulbs like MR11, and a range of others. They say that their 12 LED MR11, or maybe it was MR16, replacement was about as bright as a 5W halogen. If extrapolation is valid, ie, similar LEDs, etc., 54 LEDs would be over 20W. That would be pretty sweet for just over .6 amp draw, and the LED light will probably not need replacement in your lifetime!
This is what I love about making my own light setup. To me, it's not about saving money, because I don't, though I could certainly tell someone how to set up a super light for about $50. I love to experiment. The thrill of the hunt!
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If it ain't broke, mess with it anyway!