<VV> LED Headlamps no Corvair

[jvhroberts at aol.com]

HID is still more efficient, by a BUNCH! It puts out about 90 lumens per watt, whereas power LEDs suitable for headlights are doing about 25 lumens per watt, which is about what a low voltage halogen does. Agreed, the electronics are pretty sophisticated for HID, but they are efficient. LEDs, to be efficient, also require a PWM current regulator so as not to burn away power through a wasteful current limiting resistor. Cooler? Not yet, maybe never. LEDs simply cannot radiate away heat, because the acceptable non destructive temperatures are too low. It has to be dissipated by conduction or convection. HID and halogen operate at such high temperatures that most of the heat they generate is radiated out with the light. Longevity isn't much of an issue with HID, as the projected life span is several times that of halogens, and for most users, will outlast the car. And due to the high cost of LEDs, they are rather overdriven to keep the installation costs down. Shame, because most power LEDs are most efficient at around half of max rated power. 

Cost? Well, LEDs are DAMN expensive on a $ per lumen basis. HID is next, and halogens are dirt cheap! LEDs are getting cheaper, but the lower floor is limited to a rather high level due to the more complex construction compared to either HID or halogens. HID bulbs are actually VERY simple! 


-----Original Message-----
From: tony.underwood at cox.net
To: jvhroberts at aol.com; corvairduval at cox.net; virtualvairs at corvair.org
Sent: Mon, 12 May 2008 6:17 pm
Subject: Re: <VV> LED Headlamps no Corvair




---- jvhroberts at aol.com wrote: 
> Yep, they're here! 

Now, I was talking about stuff you buy at Auto Zone to stick in your 'Vair.   In 
time, I'd like to see such headlamps available... for an affordable price.   
Volume would do it, although I bet there would have to be something that would 
allow retrofitting, like a reflector that would accept a plug-in emitter.   

> Although, at this point, LED headlamps are no more efficient than halogen. 

...at this point.  I'm talking about down the road a couple of years or so.   I 
suspect that LED lamps will show up in force and be not only brighter but MUCH 
cooler running.   

> HID still beats LED hands down in efficiency.   

??   I'd be willing to take a bet on that.   HID uses a voltage upverter, high 
strung xenon tubes, as well as considerable electronics.  They also are not 
likely to last as long as the LED lamps, which even now boast pretty respectable 
life spans IF they're not overdriven.    The circuitry necessary to power the 
HID lamps is rather daunting, compared to other lighting systems.   Cost is also 
a BIG factor.  

Sure, HID is kewl, but it's damned expensive.   


> But the GWhiz factor is there! 

...same as the LED lamps if/when they ever make their way into mainstream use.   
;)     Whatever the result, they WILL beat the HIDs in price, that's for sure.  


After all, we ARE talking 'Vairs here... and frugality is something to consider.  
;) 


tony..