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[TR] Comparison of headlamp current draw.

Subject: [TR] Comparison of headlamp current draw.
From: spamiam at comcast.net (spamiam at comcast.net)
Date: Mon, 11 Apr 2011 19:57:31 -0400
References: <76167E44935248829BA2B57954C8D539@I7Quad> <09a001cbf89f$d21410d0$763c3270$@rr.com>
I have been in the process of upgrading my headlights.  Boy, did they need 
it!

I had some old original Lucas sealed beams, some new (but at least 12 years 
old) Sylvania tungsten (not halogen) sealed beam lights, and my new H4 with 
55/60 bulbs.  I tested them on my bench power supply which I am in the 
process of building myself, so the current measurements are not extremely 
well calibrated, but definitely comparable to each other.

Tested at a regulated 12V, because that is where most bulbs have their 
wattage specified by the manufacturer

Lucas:
     Low:  3.1 Amps (37 watts)
     High:  3.89 Amps (46.7 watts)

Sylvania:
     Low:  3.94 A   (47.3W)
     High:  4.65 A, (55.8W)

H4:
     Low: 4.73 A  (56.8W)
     High: 5.23 A (62.8W)

It would appear that my old Lucas lights were in NO danger of melting my 
wiring or switches!  Even the plain old Sylvania sealed beams would have 
been a noticeable improvement.  But the H4's with relays ought to be 
wonderful.

BTW, the SLR-576 driving lights only draw 3.62A (43.4W).  Probably the good 
H4 lights will be more effective than BOTH my old Lucas lights PLUS the 
SLR-576 lights!

One of the reasons I did this test, other than interesting results, was that 
I needed to determine whether the original plugs needed to be re-indexed to 
fit the H4 bulbs.  Many years ago I put Cibie Z-beams with H4's on my 1982 
Honda Accord, and I needed to use an adapter plug to get it to work 
properly.  I had thought I would need to move wires around, but the H4 
terminals are the same as the old sealed beam terminals

-Tony 


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