"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://www.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.geocities.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/