"Build" my own light kit (with perhaps over voltage)

[Martin TöRnsten]

Hi!

I'm thinking of building my own light kit. I'm in the
process to buy a small light housing (the CatEye alloy
house, who is for example included in their ABS-30 kit),
build my own pack with R6 Ni-MH batteries, buy a delta V
detection charger (who can charge cells individually), and
possibly a over voltage regulator (I have seen some "home
made" kit to buy on Internet, who isn't directly cheap, but
OK price).

What effect do you recommend (10W, 15W, 20W, etc) for a road
racing bike going on dark, but also half lit roads, and
should choose "flood" or "spot" version?

Thanks for any recommendations as I can't afford to by every
type of bulb at once and try for myself!

Also what battery types would you suggest?

Any one here who has build such a kit with a over voltage
regulator? Is it wort the extra expense, and what model do
you recommend?

Thanks!

Martin

 

[Chalo]

Martin Törnsten <[email protected]> wrote:

> I'm thinking of building my own light kit. I'm in the
> process to buy a small light housing (the CatEye alloy
> house, who is for example included in their ABS-30 kit),
> build my own pack with R6 Ni-MH batteries, ... Any one
> here who has build such a kit with a over voltage
> regulator? Is it wort the extra expense, and what model do
> you recommend?

I assume you are talking about running a light designed for
2 alkaline cells with 3 NiMH cells instead. So you wish to
drop your voltage from 3.7V nominal to 3.0V nominal. Any
voltage regulator that can do this will eat up as much or
more power as a resistor or diode chosen to accomplish the
same thing.

This is a 1.5W light, right? I'll do the numbers as if it
were. A normal diode drops voltage about 0.7 volts, so if
you use one in series with the bulb, that should do the
trick. The problem is that as the battery voltage falls, a
diode keeps subtracting the same 0.7V, so dimming will
happen sooner than if you use a resistor.

This is a 1.5W light, right? I'll do the numbers as if it
were. 1.5W at 3V means the normal current is 0.5 amps. V=IR
so if V is the 0.7V drop you want across the resistor, and I
is the 0.5A current under normal conditions, then you'll
need a 1.4 ohm (or thereabouts) resistor to get your voltage
drop. Get a 1/2 watt resistor so you don't overcook it. The
advantage here is that as the battery voltage diminishes,
the current across the circuit, and therefore the voltage
drop across the resistor, will also decrease. So it'll be a
little bit more efficient than if you just used a diode.
Plus you won't have to worry about putting it in backwards.

Chalo Colina

 

[Steve Knight]

On Fri, 23 Apr 2004 17:32:07 +0200, Martin Törnsten <[email protected]>
wrote:

>Hi!
>
>I'm thinking of building my own light kit. I'm in the
>process to buy a small light housing (the CatEye alloy
>house, who is for example included in their ABS-30 kit),
>build my own pack with R6 Ni-MH batteries, buy a delta V
>detection charger (who can charge cells individually), and
>possibly a over voltage regulator (I have seen some "home
>made" kit to buy on Internet, who isn't directly cheap, but
>OK price).

first get a miniature halogen fog light for a car. http://w-
ww.truckaddons.com/Catalog/subpages/EagleEyeFogDriving01.asp

the second one down. it is a mr11 based light no a mr16 like
the site says. it is really small and looks nice. AI have 4
of them if you want one cheap.

>What effect do you recommend (10W, 15W, 20W, etc) for a
>road racing bike going on dark, but also half lit roads,
>and should choose "flood" or "spot" version?

well that depends on how long you want the batteries to last
and how much light you need. it also depends on the speed
you go. myself I liked 20 watts overvolted running at 16
volts this puts out a nice white very bright light.You want
something between about 8 degrees and 17 degrees. it depends
on the bulb and how much power you have. the less power the
smaller the angle you need. here is a great bulb source
http://www.bulbsource.net/ the site is out of date
http://www.cs.indiana.edu/~willie/lvr.html but willie sells
Custom LVR's He can program them for the voltage you want.
they keep the batteries from fully discharging and they let
you overvolt the bulb by however much you want. He can put
different switches and you can switch between power levels.
mine was 16v 14v 12v and 10v. it was fully sealed and used a
magnet to turn it off and on. I went a bit overboard I Use a
mr16 light I use a 4700k bulb that is really white but they
only come in 35watts. so I run it at 12v it is very bright
and lights the whole lane and a little but of three other
lanes. but it only runs for about 1.25 hours with 19v
3000mah C cells.

>Also what battery types would you suggest?

it depends on how much light you want. if you don't go over
20 watts or maybe don't overvolt the 4/3 aa 4000 or 45000
MAH cells will give you the longest run time
http://www.batterystation.com/nicads.htm I have the sanyo
sub 3000mah cells.

I bought a good computer controlled charger for rc cars and
such. cost me 45.00 including shipping.

--
Knight-Toolworks & Custom Planes Custom made wooden planes
at reasonable prices See http://www.knight-toolworks.com For
prices and ordering instructions.

 

[Martin TöRnsten]

Captain's log. On StarDate 23 Apr 2004 17:08:26 -0700 received comm from
[email protected] (Chalo) on channel rec.bicycles.tech:

: Martin Törnsten <[email protected]> wrote:
:
: > I'm thinking of building my own light kit. I'm in the
: > process to buy a small light housing (the CatEye alloy
: > house, who is for example included in their ABS-30 kit),
: > build my own pack with R6 Ni-MH batteries, ... Any one
: > here who has build such a kit with a over voltage
: > regulator? Is it wort the extra expense, and what model
: > do you recommend?
:
: I assume you are talking about running a light designed
: for 2 alkaline cells with 3 NiMH cells instead. So you
: wish to drop your voltage from 3.7V nominal to 3.0V
: nominal. Any voltage regulator that can do this will eat
: up as much or more power as a resistor or diode chosen to
: accomplish the same thing.
:
: This is a 1.5W light, right? I'll do the numbers as if
: it were. A

Not quite. I'm talking buying a light house (sold separate
as a spare part) from this kit:
http://www.wiggle.co.uk/?ProductID=5300002085

But I'm open for suggestions for (preferably small and neat)
light houses from other manufactures as well (but not too
expensive, I can buy the above for about £16.00 = 27,40 USD
= 23,06 EUR).

The over voltage regulator I was thinking about was
something like this:

http://www.trailheadlights.com/lightbrain/ http://www.geoci-
ties.com/sunsetstrip/concert/2301/index2.html

Best regards,

martin törnsten

--
http://82.182.73.126/

 

[Chalo]

Martin Törnsten <[email protected]> wrote:
>
> Chalo wrote:
> : I assume you are talking about running a light designed
> : for 2 alkaline cells with 3 NiMH cells instead. So you
> : wish to drop your voltage from 3.7V nominal to 3.0V
> : nominal.
>
> Not quite. I'm talking buying a light house (sold separate
> as a spare part) from this kit:
> http://www.wiggle.co.uk/?ProductID=5300002085

Ah. I thought you were dealing with something like the
venerable Cateye HL-500.

> The over voltage regulator I was thinking about was
> something like this:
<snip>

I think you should match the number of NiMH cells to the
voltage of the bulb you pick, and go without a regulator.
Most voltage regulators consume about 20% of the power
delivered by the battery, and NiMH cells have a very flat
discharge voltage anyway, dropping quickly from about 1.4V
to about 1.25V, then remaining above 1.2V for almost their
entire discharge. If you use a regulator that will boost
very much below 1.0V per cell, you risk trashing your cells
from discharging them too deeply.

If you are using high-output incandescents, you are probably
running 12v, so just use 11 or 12 rechargeables (12V nominal
systems are more like 14V in operation) and keep it simple.

Chalo Colina

 

[suzyj]

Originally posted by Martin TöRnsten:

> What effect do you recommend (10W, 15W, 20W, etc) for a road
> racing bike going on dark.

I find the Vistalite 5W globe (comes with the nightstick light) works very nicely. This is a narrow (I think) spot.

Also what battery types would you suggest?

a size NiMH batteries are good - available around 3.5Ah. Also Sanyo make 3Ah sub-C NiMH cells which are good stuff.

One that I'd really like to try are Kokam Lithium Polymer cells. They make a 3.7V, 3.27Ah cell that weights just 64 grams. Four of these (with an appropriate regulator) would power my 5W globe all night long. Just the ticket for Audax riding.

Regards,

Suzy

 

[Martin TöRnsten]

Captain's log. On StarDate 26 Apr 2004 15:40:36 -0700 received comm from
[email protected] (Chalo) on channel rec.bicycles.tech:

: Martin Törnsten <[email protected]> wrote:
: >
: > Chalo wrote:
: > : I assume you are talking about running a light
: > : designed for 2 alkaline cells with 3 NiMH cells
: > : instead. So you wish to drop your voltage from 3.7V
: > : nominal to 3.0V nominal.
: >
: > Not quite. I'm talking buying a light house (sold
: > separate as a spare part) from this kit:
: > http://www.wiggle.co.uk/?ProductID=5300002085
:
: Ah. I thought you were dealing with something like the
: venerable Cateye HL-500.

Well, I actually have one of those (HL-500II), but find that
it sometimes gives too little light in some conditions, but
are otherwise great lights.

I have been thinking of upgrading it with a 6W bulb, and/or
over volt it as well, but I'm not sure the plastic house and
reflector in it is build for it.

That's why I have been thinking of buying a separate light
house (preferably the alloy lamp house mentioned), and still
have the HL-500II for backup light, or in less demanding
situations.

: > The over voltage regulator I was thinking about was
: > something like this:
: <snip>
:
: I think you should match the number of NiMH cells to the
: voltage of the bulb you pick, and go without a regulator.
: Most voltage regulators consume about 20% of the power
: delivered by the battery, and NiMH cells have a very flat
: discharge voltage anyway, dropping quickly from about 1.4V
: to about 1.25V, then remaining above 1.2V for almost their
: entire discharge. If you use a regulator that will boost
: very much below 1.0V per cell, you risk trashing your
: cells from discharging them too deeply.

It seems that it (and some other voltage regulators
specially build for these type of battery lights) consumes
very little power, but I agree that if it's really not
needed that much I prefer to not add that extra cost (they
seems to be quite expensive). Thanks for all the tips!

Best regards,

martin törnsten

--
http://82.182.73.126/