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