I should have used my bench top meter, but I didn't :-)

But if the handheld meter values are anywhere close to actual, then it's pretty  impressive the amount of light I can get from the two lamps for only 3 amps.

I was guessing some sort of buck converter and current reg. I meant to try something but completely forgot. I was going to use one of my pwm motor controllers to drive a dc fan and see if I could detect a strobe effect from the light.

Anyway, I've concluded that while pretty good, this particular led drop in bulb is a dead end for H4 application. While the placement of the led elements in the horizontal ( perp to the wide axis of the lamp) is pretty good, the horizontal placement can never be exactly like a halogen filament.

Compromised as it is, the beam pattern ain't that bad. The low power draw is exceptional.

Alistair

> On Feb 13, 2017, at 3:03 PM, Dennis Haynes <d23haynes57@hotmail.com> wrote:
> 
> A lot of the LEDs are rated in very confusing manners like light output or power being listed for the pair. As for measuring actual current draw most of these are using switching type power supplies so the current draw is not linear. You need "true RMS' metering to get real measurements. Many of these will work with 12 and 24 systems. 
> 
> Dennis
> 
> 
> -----Original Message-----
> From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of Alistair Bell
> Sent: Monday, February 13, 2017 5:26 PM
> To: vanagon@GERRY.VANAGON.COM
> Subject: Yet another led H4 blog post
> 
> Truly in the beating a dead horse department, I wrote a little more on the led H4 bulbs I've been trying out.
> 
> Some basic electrical measurements, some unexplained discrepancies, some close up beam pattern pics.
> 
> https://shufti.blog/2017/02/13/vanagon-beating-the-h4-led-subject-to-death/
> 
> Alistair