Re: LED light results -- short
- From: Neon John <no@xxxxxxxxx>
- Date: Sun, 02 Apr 2006 23:25:27 -0400
On Sun, 02 Apr 2006 14:38:40 GMT, GaryO < @ . > wrote:
On Thu, 30 Mar 2006 00:14:39 -0500, Neon John <no@xxxxxxxxx> wrote:
I have a nifty little 7 watt 12 volt-operated, bayonet-base CF that
was sent to me for review (by an importer that went out of business,
unfortunately) It outputs many times more light than 7 watts' worth
of LEDs. And it's a much more pleasing light, having a spectrum
similar to incandescents.
This sounds like just what I've been needing!! What are the
dimensions of it? Do you know if anyone else offers it?
It's a spiral tube lamp. Overall length is about 3" and the spiral
diameter is about 1.5". It won't fit in the RV standard cheezy square
flat plastic fixtures but it would fit in a nicer wall fixture where
the bulb is under a shade or whatever.
I don't know where one could get this exact bulb but there is a flood
of ChiCom 12 volt CFs available now. Google for "12 volt CF lamp" and
enjoy the flood :-)
Here's the first hit:
http://www.realgoods.com/shop/shop3.cfm/dv/3/dp/301/ts/3033509
This lamp looks exactly like mine except that mine has the
automotive-style bayonet base. I'll bet that the bayonet base is an
option.
I've been considering taking one of the inexpensive 7W Coleman battery
operated fluorescent lamps and gutting it, to use for RV interior
lighting. I'd like to fit it inside my existing incandescent (#1141
bulb) fixtures. (I don't like the large size of the thinlites, and
their tiny power switches.) Since it is intended to run from D cells,
it should have pretty decent overall efficiency, I'd just need to
adapt it to 12V from its stock 6V. The problem that I've encountered
at the moment is that the bulb is just a tad too long for my fixture.
I've noticed at Wallyworld there are several types of replacement
lamps for those lanterns including a spiral lamp.
The problem with those lanterns is that the driver is crap, to use a
technical term. There are two major issues with electronic drivers -
filament drive and mercury migration. The filament drive must be
adequate or else the electron emission will be too low, positive ions
will collide with the filament and knock off bits of same. The result
is blackening of the tube ends and short life. Sometimes very short
life.
Mercury migration is a phenomenon that happens when there is a little
bit of DC bias on the AC driving signal to the lamp. This can come
from several sources - asymmetrical waveform, inadequately driven
filaments, resulting in one end of the tube acting as a rectifier,
actual DC bias from the driver, etc. What happens is that all the
mercury in the tube gets driven to one end, the end that is the most
negative. That end of the tube stays bright but the rest of the tube
gets progressively dimmer and dimmer.
I have several of those Coleman lanterns (I guess that it's a
sorta-hobby of mine accumulating interesting things that give off
light :-) All but one (out of production for a long time) have one or
both of these problems. Neither seem serious in the original
application simply because the lantern can't be used for long
intervals because of the limited life of the batteries. Hook that
sucker up to a source of power, however, and the problem gradually
becomes serious.
One of the things that impressed me about the ThinLites is that
they've mostly avoided the filament drive problem and have completely
avoided the merc migration problem with a very simple ballast circuit.
I don't like the ThinLites for the same reasons but given that at 6'7"
tall, my head scrapes the ceiling as it is, having a CF sticking down
just doesn't cut it :-)
If you can't make a 12 volt CF fit then you could drive an "organ
tube" CF with a 12 volt neon transformer. This guy makes the best
ones available, IMO.
http://www.t2-neonpower.com/t2_list.html
That "midget" unit, the first of the 12 volt units, would do the job.
The 30ma current that standard neon uses is about 1/10th that of CFs
so the brightness would drop accordingly. OTOH, 3KV will run many
tubes in series. Tech 22 is a small company and the guy who owns it
(can't pop his name out of the memory banks at the moment) will
willingly do small custom jobs such as supplying more current. I
think he has 60 and 120 ma units that are sorta non-catalog but also
sorta off-the-shelf items.
I provide this last bit as an option but I'd personally much prefer
the 12 volt CFs. I'd put forth a lot of effort to make one adapt.
One other thought. In my last article I mentioned that Welch Allyn
SolArc HID lamp that I'm using on my scooter for a headlight and as a
reading light in my MH. WA also makes a "bare bulb" version. Here is
the web page:
http://www.walamp.com/lpd/webstore/detail.tpl?partnumber=M10N001-1
Buying from WA, just the bulb costs more than my entire light from
TrailTech. The reason I mention this bulb is that it has become quite
popular for diving lights. It has the light output of a 55 watt
quartz halogen with only 13 watts' draw (this includes the 10 watts to
the bulb and the ballast overhead). I can't point you to a URL off
the top of my head but I've seen this bulb offered for sale as a
replacement dive light part in the $50 range.
The arc tube in that lamp is barely the size of a grain of rice. The
whole lamp is probably less than an inch long. The light is
dazzlingly blue-white. There is some UV content which makes text
really pop off the page of a book or magazine. There is very little
heat produced. I doubt that the outer envelope gets anywhere near as
hot as an incandescent bulb.
the ballast is about the size of 4 or 5 quarters stacked up. Tiny
l'il thang!
John
---
John De Armond
See my website for my current email address
http://www.johngsbbq.com
Cleveland, Occupied TN
A foolish consistency is the hobgoblin of little minds.-Ralph Waldo Emerson
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