A battery ? and Halogen vs LED

On 10 Nov 2005 10:32:32 -0800, wrote:

Hi Everyone,

Time to get the light going again. I have a few questions:

I have a Silva 480 10w/20w halogen headlight with a 6V 4.5aH battery. I
can't find the charger. It's here someplace, but I don't feel like
rummaging around for it. It's not a smart charger, it a
burn-down-your-house-if-you-forget charger. I have access to a charger
made for my son's Lego Dirt Crusher r/c car, that may work just fine.
Can someone with knowledge of such things help me out? The r/c car has
a 7.2 volt, and on the charger it says the output is 6-9.6V 550mA. It
would be nice to be able to use if for convenience, and because it has
auto shut-off. The polarity is correct and the connector is the same.
But is that shut-off calibrated to 7.2V? Will it fry my battery or burn
down my house?

Also what are the advantages of LED set-ups? The Silva 480 has a range
of 120 meters according to Silva. It's pretty bright. I am comfortable
going up to say 30km/h with it. Would some LED system give me more
light?

Thanks!

Joseph

You should be fine with the charger *IF* the battery is a gelled lead-acid type. These are
very forgiving of input voltage. Although the battery states it's a 6 volt, it normally operates
higher and will take a good 7+ volts to charge. My charger puts out 7.5V when it's connected to my
battery (also 6V, 4.5 AH gelled lead acid)
I have a 10 watt halogen and I've tried the LED Luxeon lights. They're getting there but have a
way to go yet. I have a cheap one on my helmet as a backup (I ride the Trans-Canada trail to work
and it's pretty dark in the morning). It's a 3 watt Luxeon from Radio Shack (now 'The Source')
which at least lets me stay on the trail if my main light dies). Keep your eye on the new LED based
lights as I'm sure it won't be long before they deliver the brightness of your halogen.

On Fri, 11 Nov 2005 01:43:07 -0800, joseph.santaniello wrote:

The 10W setting is useless on a bike in my opinion. I need to use the
20W setting. The battery seems to last about 2 hours, which is fine for
my needs. The only thing is it would be nice to have even more light
further, so I am not in danger of out-running my vision range. What
about HID lights?

I don't feel I am out-running my vision range with my diNotte, except on
one very fast downhill I did last night, when blinded by an oncoming car
with high-zoot headlights itself. But this happens under those conditions
while driving, too.

But anything under 25mph works for me.

--

David L. Johnson

__o | Let's be straight here. If we find something we can't
_`\(,_ | understand we like to call it something you can't understand, or
(_)/ (_) | indeed even pronounce. -- Douglas Adams

David L. Johnson wrote:
On Fri, 11 Nov 2005 01:43:07 -0800, joseph.santaniello wrote:

The 10W setting is useless on a bike in my opinion. I need to use the
20W setting. The battery seems to last about 2 hours, which is fine for
my needs. The only thing is it would be nice to have even more light
further, so I am not in danger of out-running my vision range. What
about HID lights?

I don't feel I am out-running my vision range with my diNotte, except on
one very fast downhill I did last night, when blinded by an oncoming car
with high-zoot headlights itself. But this happens under those conditions
while driving, too.

But anything under 25mph works for me.


Is there other ambient light? I ride in essentially pitch darkness.

Joseph

wrote:
David L. Johnson wrote:


I don't feel I am out-running my vision range with my diNotte, except on
one very fast downhill I did last night, when blinded by an oncoming car
with high-zoot headlights itself. But this happens under those conditions
while driving, too.

But anything under 25mph works for me.


Is there other ambient light? I ride in essentially pitch darkness.

FWIW, I think my headlight works best in pitch darkness. After a
couple minutes of darkness adaptation, my eyes are quite sensitive to
the light it puts out.

Of course, riding on well-lit city streets, I could see even without
the headlight. In that situation, it's for being visible, not seeing.
I'd say the worst conditions are when running from bright to dark areas
repeatedly, or when oncoming bright lights (car or bicycle!) blind you.

A hat with a brim works well for the latter problem.

- Frank Krygowski

wrote:

Is there other ambient light? I ride in essentially pitch darkness.

Joseph

You ride in some very strange places. Unlit tunnels? Thick forest?

On an open road the moon often provides enought light to see by.

On dark roads you need very little light to see once your eyes are dark
adjusted, so an LED headlight works well.

It is only when competing light sources (e.g. car lights) prevent dark
adaptation that a brighter light is needed.

Andrew Webster

On Fri, 11 Nov 2005 10:06:45 -0800, joseph.santaniello wrote:



Is there other ambient light? I ride in essentially pitch darkness.

My usual commute is on city streets, where there is some, but variable,
ambient light. Last night involved stretches only lit by the stars. Very
peaceful. But, for me, such conditions are less demanding of a light --
and my diNotte seemed to light up the whole road ahead quite well -- than
a road with no streetlights, but with occasional oncoming traffic.

--

David L. Johnson

__o | Anyone who is capable of getting themselves made President
_`\(,_ | should on no account be allowed to do the job. -- Douglas Adams
(_)/ (_) |

Andrew W wrote:
wrote:

Is there other ambient light? I ride in essentially pitch darkness.

Joseph

You ride in some very strange places. Unlit tunnels? Thick forest?

On an open road the moon often provides enought light to see by.

On dark roads you need very little light to see once your eyes are dark
adjusted, so an LED headlight works well.

It is only when competing light sources (e.g. car lights) prevent dark
adaptation that a brighter light is needed.

Andrew Webster

In the forest or backroads on an overcast night at 60 deg North in the
winter it gets pretty dark. Sometimes there is moonlight, and if there
is snow around, I can usually turn off the light completely, but when
it's needed, it's needed.

Joseph

wrote:
I'd say the worst conditions are when running from bright to dark areas
repeatedly,

Definitely.

or when oncoming bright lights (car or bicycle!) blind you.

A hat with a brim works well for the latter problem.

Unless you're at the plateau of a hill and about to head down, and
oncoming cars are going uphill, in which case the brim would have to be
way to low to do any good.

All the fresh asphalt in my area has given me a great opportunity (if
you can call it that) to experience the difference in the effectiveness
of lighting on smooth, very black blacktop vs. older, grey-ish pavement.

Give me the older stuff any night! The roughness is barely noticeable
in road feel (and is more an aural thing). If this new pavement stays
that smooth and black, I might actually have to get an HID (or at least
a 20W halogen flood) to feel comfortable riding on it.

Just tonight I was in the middle of the lane, thinking I'm seeing stuff
just fine with my 10W halogen helmet light and 2 1W LED lights and I
roll over a pothole (or maybe an open utility access thingy) that scares
the heck out of me. I didn't see a thing. It was bad enough to knock
my front brake out of whack.


--
I do not accept unsolicited commercial e-mail. Remove NO_UCE for
legitimate replies.

Matt O'Toole wrote:

I'm curious too. I wonder if the rectifier you'd need to convert the
dynamo's output to DC for the LED would waste more power than the LED
would save (vs. a halogen). It would be nice not having to worry about
bulbs burning out though.

If you want to run a single LED then a rectifier is needed to fully utilize
the generator's AC output. If you're willing to run multiple LED's it's
possible to construct a "self rectifying" setup.

I just did it, using four Luxeon 1 watt Star/O LEDs from
www.theledlight.com. Got it working this morning and gave
it a test ride just after nightfall.

On balance one gets quite a lot more light from LEDs than from
a halogen bulb, but the LED optics furnished with the Star/O are
not exactly pencil-sharp. The beam spread is claimed to be less
than ten degrees FWHM, but it looks more like 25-35 to me. That's
not necessarily bad, it's much easier to read street signs.

Whether the efficiency gain of using multiple LEDs instead of
a separate rectifier is worth the money isn't clear to me. The
four LED setup used $60 worth of LEDs, a single 3 watt Luxeon is
about $20 and can be equipped with standlight capability. My
setup is incompatible with standlight function.

I'll try to put up a short webpage with pictures later this weekend.

bob prohaska

wrote:
tspoon wrote:


have to agree - I run a 3 watt L.E.D off my hub dynamo - it's 90%
adequate but won't be as bright as a 10 watt halogen.


Can you give us details? I'd be curious. Thanks.

- Frank Krygowski


The dynamo is a Shimano NX30 (theres more efficient ones out now, but
this one is fine atm). I feed the 6 volts into a bridge rectifier made
with 4 schottky diode of some very common type I can't quite remember
just now. I added a Pi filter using some 32v 4000 odd uf caps and a hand
wound inductor. I did this to try to stop the low resistance offered by
the next stage ( a constant current regulator from taskled.com ) from
collapsing the dynamo voltage too much. I'm not sure how well it's
worked though. At around 20 km/h the dynamo voltage output is 5.6 volts
AC at 520 mA. The constant current regulator is set for 700mA to
actually only output around 2.6 watts and I don't think the dynamo is
supplying even this much. Possibly only 2.2 - 2.3 watts, as the
rectifier is probably dropping around .2 of a volt. As I said it's 90%
adequate although maybe I'm just used to it now. It is a very bright,
very white source which is visible from a very long way away.

I stuck all the electrical stuff in a small box attached to my front
carrier. I wired up the lights in speaker wire from a set of car
speakers I bought once. The wiring attaches to the box with a 4 pin
microphone plug so I can take it off easily for repairs/alterations. I
mounted the LED in a small Spotlight housing from an auto store which
was designed for a 50mm 2 pin spotlamp. The LED itself is a Luxeon 3
watt with a narrow beam fraen lens. I also wired back to my two flashers
in series, and when it's light I turn a switch and charge the 2
batteries in each flasher through a low drop out type regulator set at
5.6 volts. All in all it's made for a very reliable system (I do about
60% of my commuting in the dark year round) and I'm OK with the light
levels but keen for future developments.

A multi LED system would probably be more efficient as these type of
LEDs are more efficient when driven at a fraction of their rated output,
but it makes for a more expensive and complex system to start off with.