I had the general impression that 12v headlights on motorcycles and somesuch draw 10-15amps of power at 12v from the battery.
I found some 36v DC to 12v DC converters on eBay, but the only ones that output in 10+ amps are incredibly expensive (more than my $30 budget)
yet i keep seeing examples of people using dc-dc converters to do exactly what i am, and having no problems, and these converters output as low as 3 amps!
what's the deal? can most automotive headlights be plugged into the 36v circuit through one of these 3 amps converters and still function fine? Or have i been reading a bunch of hogwash?
I would question your original assumption that headlights require 10-15 amps. On my motorcycle the DC-DC converter is ?12? (maybe 15) amps max for the whole 12v system, that's the headlights and turn signals and brake light etc. IIRC the headlight was 4-5 amps.
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I got the 10-15 amps estimate from a parts guy at a local motorcycle shop. He seemed pretty informed, but he did mention that he was drawing his conclusions from the standard fuses (which blow at 20 amps), so he may have been guessing pretty wildly.
All i really need for MY bike is the blinker module and headlight, that is assuming the 12v blinker i buy can send a powerful enough current to the 36v head and tail lights, Since the current blinker makes this really annoying rhythmic screech instead of the typical "click-clack".
speaking of which, anyone have a 36v scooter whose STOCK blinker module makes the usual click clack sound?
OH NO HOW DID THIS GET HERE I AM NOT GOOD WITH COMPUTER
A standard motorcycle headlight is generally a standard car bulb in a slightly different shaped housing. A standard car bulb is 55 watts. That means 4.6amps x 12volts, for each bulb (though you are really running closer to 13v, not sure how that changes things).
Anything brighter than 55watts (in an incandescent) is generally not allowed on the road by the DOT. An HID system generally uses 35watts to achieve slightly better brightness, but it's brightness is also limited by the DOT.
Motorcycle driving lights are often 35w each (see Motolights, for example).
My electric vehicle: CuMoCo C130 scooter.
On my moped conversion, I first used a Tyco 36V-75DC 40 watt unit that I bought on ebay, but the problem was that at full throttle, my system voltage dipped to below 33V, which was the low-volt cutoff for the DC-DC converter. Not good that your headlights die at full throttle or at the end of the battery life!
So I made my own DC-DC converter using a LM2576HVT-12-ND buck converter from National Semiconductor. It does 3A continuous and 5A peak, which is between 36-60 watts. Instead of the old incandescent bulb, I replaced the headlight with a high-power white LED bulb from a flashlight, and it works great, even brighter than the original bulb. It consumes about 5 watts.
I've blogged about my DC-DC converter here: http://visforvoltage.org/blog/nasukaren/4422
Working on a Piaggio Boxer (mo-ped) EV conversion: http://gpsy.com/ev