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Home > Archive > Alternative Power sources > March 2008 > Re: Bicycle Lighting System?
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Re: Bicycle Lighting System?
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| Ulysses 2008-03-02, 5:25 pm |
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"(PeteCresswell)" <x@y.Invalid> wrote in message
news:c5ijs39mg1hg6flkr4upf6ioev26g267jm@4ax.com...
> Posted here bco the obvious expertise of group members in matters
> electrical.
>
> Bicycle-mounted front wheel generator (alternator?) hub - puts
> out AC.
>
> Numbers on the hub say 6 volts, 4 watts.
>
> Putting a volt meter on it, I get 3v at walking speed (2.5 mph),
> 6v at 5 mph, and more as speed increases. With me on it, I
> don't see it ever getting up to 20v, but 10-12v could be fairly
> common.
>
> From what I've heard, there is a problem with using bulbs wired
> direct. You get a bulb that won't burn out at the higher
> voltages, and it's dim where most of the riding happens - at 5-10
> mph. It also goes out when the bike goes really slow or stops.
>
> I'm basically clueless re/electrical stuff, but what I've gleaned
> so far is this:
> ------------------------------------------------------------------
> 1) Something called a bridge rectifier will convert AC to DC.
>
> 2) If I put a couple of 1.5v NiCad batteries end-to-end, but
> across the rectifier's output, they'll be charged when the
> output exceeds 3 volts and supply 3 volts when the output is
> less than 3 volts - limiting the voltage that any bulb or
> LED emitter is subjected to about 3 volts.
>
> 3) There are myriad 3-volt LED lights out there that I can choose
> from for the lighting part. Red, white, steady, flashing....
> you name it, somebody's selling it.
> ------------------------------------------------------------------
>
> Bottom line, I want maximum brightness when just noodling along
> at 3-7 mph, but don't want tb burning out bulbs if/when I go down
> a hill fast.
>
> My primary concern is the lighting that's visible to closing
> traffic from my back. I avoid roads with any significant amounts
> of traffic, but even in the quietest neighborhoods and parking
> lots there's some exposure.
>
> The more light and the more attention-getting on the rear the
> better, since I'm competing with cell phones, text messages,
> email, and navigation screens.
>
> I use a hand-held flashlight for the front lighting and it works
> well. (Lowe's TaskForce 4w LED... one *brave* little flashlight)
> .. but I also want a token front light attached to the bike and
> wired into the system in case some cop wants to get technical or
> the hand-held fails when I still have to get back to my home.
>
> Am I on the right track? Seems like the capacity of the
> rectifier would be a half amp max (4w/20v + fudge factor).
>
> One more time: I'm clueless about electrical stuff.
> --
> PeteCresswell
You could make a bridge rectifier with four very small diodes and use an
adjustable voltage regulator (LM317 Radio Shack). You would only need to
add a couple of capacitors and resistors, one being adjustable, and the
whole thing would be not much bigger than a book of matches. You could then
choose 3 volts or 6 volts (3 would be easier) as long as the bulb does not
use more than 1.5 amps. If necessary you could use the bicycle for a heat
sink. The Radio Shack regulator has the circuit diagram on the back of the
blister pack.
| |
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| "Ulysses" <eatmyspam@spamola.com/> wrote in
news:13sm0abgfku3a61@corp.supernews.com:
>
> "(PeteCresswell)" <x@y.Invalid> wrote in message
> news:c5ijs39mg1hg6flkr4upf6ioev26g267jm@4ax.com...
>
> You could make a bridge rectifier with four very small diodes and use
> an adjustable voltage regulator (LM317 Radio Shack). You would only
> need to add a couple of capacitors and resistors, one being
> adjustable, and the whole thing would be not much bigger than a book
> of matches. You could then choose 3 volts or 6 volts (3 would be
> easier) as long as the bulb does not use more than 1.5 amps. If
> necessary you could use the bicycle for a heat sink. The Radio Shack
> regulator has the circuit diagram on the back of the blister pack.
I was thinking along the same lines -- (without the actual knowledge to
build it) -- if you wanted, you could rig the heat sink as hand warmer
grips!
Like four wheelers have hand warming grips, so when your batteries are
getting too much voltage you could shunt into resisters in the grips and
keep yer mits warm 
| |
| (PeteCresswell) 2008-03-02, 8:25 pm |
| Per Ulysses:
>You could make a bridge rectifier with four very small diodes and use an
>adjustable voltage regulator (LM317 Radio Shack). You would only need to
>add a couple of capacitors and resistors, one being adjustable, and the
>whole thing would be not much bigger than a book of matches. You could then
>choose 3 volts or 6 volts (3 would be easier) as long as the bulb does not
>use more than 1.5 amps. If necessary you could use the bicycle for a heat
>sink. The Radio Shack regulator has the circuit diagram on the back of the
>blister pack.
>
I wimped on the bridge rectifier and ordered 3 from Radio Shack
(figuring I'll toast at least one klutzing around... and at three
bucks each, why not?)
Looks like I'll be getting a voltage regulator too.
Sounds obvious from the name, but just tb sure: this thing will
lock the voltage at whatever I set it to, right? So the input
voltage may vary from 3 to 20 volts, but the output will always
be, say, 3.
As far as using the bike frame for a heat sink goes, I'd expect
to find some sort of heat-conductive putty and embed the two
components in that and just stick it to someplace on the frame.
Sound right?
Where do the capacitors and resistors come in?
Capacitors to even out the flow and/or store a little for a few
seconds of light when the bike stops?
--
PeteCresswell
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| Martin Riddle 2008-03-02, 8:25 pm |
|
"(PeteCresswell)" <x@y.Invalid> wrote in message news:ihems3dfa05hsuaqac8olt1kbfr8iog093@4ax.com...
> Per Ulysses:
>
> I wimped on the bridge rectifier and ordered 3 from Radio Shack
> (figuring I'll toast at least one klutzing around... and at three
> bucks each, why not?)
>
> Looks like I'll be getting a voltage regulator too.
>
> Sounds obvious from the name, but just tb sure: this thing will
> lock the voltage at whatever I set it to, right? So the input
> voltage may vary from 3 to 20 volts, but the output will always
> be, say, 3.
>
> As far as using the bike frame for a heat sink goes, I'd expect
> to find some sort of heat-conductive putty and embed the two
> components in that and just stick it to someplace on the frame.
> Sound right?
>
> Where do the capacitors and resistors come in?
>
> Capacitors to even out the flow and/or store a little for a few
> seconds of light when the bike stops?
> --
> PeteCresswell
__________
________ | LM317 |
HUB------------------|AC +|------+-------|VIN Vout|----+------3V
| | | | | |
| | C | ADJ | R
| | 1 ---------- 1
| | | | |
HUB------------------|AC -|------+ +---------+
-------- | | |
| R C
| 2 2
| | |
\-------------+---------/
|
GND
C1 = 100Uf
C2 = 1uf Optional
R2 = 240
R1 = 180 (calc 173)
Vout = 2.916V
Ref
http://cache.national.com/ds/LM/LM117.pdf
Cheers
| |
| Ulysses 2008-03-03, 5:25 pm |
|
"(PeteCresswell)" <x@y.Invalid> wrote in message
news:ihems3dfa05hsuaqac8olt1kbfr8iog093@4ax.com...
> Per Ulysses:
then[color=darkred]
not[color=darkred]
heat[color=darkred]
the[color=darkred]
>
> I wimped on the bridge rectifier and ordered 3 from Radio Shack
> (figuring I'll toast at least one klutzing around... and at three
> bucks each, why not?)
Well, you could have bought a lot of small diodes for 3 bucks. You just
connect two in series, two others in series, the little line goes at the
top. Then you connect the two sets together at the top and bottom. You
connect the AC to the sides (inbetween the two doides) on both sides. The
top is now Positive and the bottom is Negative. I'm pretty sure you don't
even connect Negative to the LM317--that goes directly to the bulb.
>
> Looks like I'll be getting a voltage regulator too.
>
> Sounds obvious from the name, but just tb sure: this thing will
> lock the voltage at whatever I set it to, right? So the input
> voltage may vary from 3 to 20 volts, but the output will always
> be, say, 3.
The voltage could drop below whatever you set it to but it won't exceed
that. Of course first you'll have to be peddeling fast enough to get a
little more than the voltage you choose. There will be a little bit of
loss, but probably not much. One of the resistors will be variable (trim
pot) and that's what you use to adjust the voltage. A fixed resistor could
also be used but you may want to try both 3 and 6 volt bulbs. One of the
capacitors is to smooth out the ripple from the AC but you won't need a very
big one because your bulb probably won't care very much about that. I don't
remember the specs but 20 volts should be well within the input range of the
LM317. It'll probably handle something like 25-30 volts input.
>
> As far as using the bike frame for a heat sink goes, I'd expect
> to find some sort of heat-conductive putty and embed the two
> components in that and just stick it to someplace on the frame.
> Sound right?
The voltage regulator has a hole in the top. You should be able to screw it
down to the headlight or whatever (some physical designing will be
necessary). You may not even need to heat sink it unless you use a big
bulb, but I'd go with some kind of heat sinking. If you don't the regulator
might overheat and shut down. Attaching it to aluminum would be better than
steel.
>
> Where do the capacitors and resistors come in?
>
> Capacitors to even out the flow and/or store a little for a few
> seconds of light when the bike stops?
A small (100 uF) cap might keep an LED going for a little while but an
incandescent bulb would probably such it dry in no time.
> --
> PeteCresswell
| |
|
| In article <ihems3dfa05hsuaqac8olt1kbfr8iog093@4ax.com>,
"(PeteCresswell)" <x@y.Invalid> wrote:
> Per Ulysses:
>
> I wimped on the bridge rectifier and ordered 3 from Radio Shack
> (figuring I'll toast at least one klutzing around... and at three
> bucks each, why not?)
>
> Looks like I'll be getting a voltage regulator too.
>
> Sounds obvious from the name, but just tb sure: this thing will
> lock the voltage at whatever I set it to, right? So the input
> voltage may vary from 3 to 20 volts, but the output will always
> be, say, 3.
>
> As far as using the bike frame for a heat sink goes, I'd expect
> to find some sort of heat-conductive putty and embed the two
> components in that and just stick it to someplace on the frame.
> Sound right?
>
> Where do the capacitors and resistors come in?
>
> Capacitors to even out the flow and/or store a little for a few
> seconds of light when the bike stops?
Or you could get really cute, and get yourself a 3 - 32 Vdc Input
Switching Dc/Dc Converter with a 12 Vdc Output, and use a 12 Vdc
Bulb, or a 12 Vdc Multi-Element LED Light, and put a NiMH 12 Vdc
battery pack in there somewhere, and have lights whenever......
as long as you keep the pack charged.....
| |
| Warren Block 2008-03-03, 8:25 pm |
| You <you@shadow.orgs> wrote:
> Or you could get really cute, and get yourself a 3 - 32 Vdc Input
> Switching Dc/Dc Converter with a 12 Vdc Output, and use a 12 Vdc
> Bulb, or a 12 Vdc Multi-Element LED Light, and put a NiMH 12 Vdc
> battery pack in there somewhere, and have lights whenever......
> as long as you keep the pack charged.....
Which might also be more efficient than a linear voltage regulator.
Watts produced by physical effort are hard work.
--
Warren Block * Rapid City, South Dakota * USA
| |
| (PeteCresswell) 2008-03-03, 8:25 pm |
| Per You:
>Input Switching Dc/Dc Converter
Googling, I see a lot *about* them, but nothing for sale yet.
I'll keep looking though.
Sounds like the way to go, though since the Wikipedia article
cites "80-98%" efficiency and, presumably, the linear converters
are a lower efficiency as they dump the excess into heat.
I thought I had a heat issue with the inverter - but I just
realized that the one I ordered will handle 25 amps... so I'm
betting my dinky little half amp is barely going to warm it up.
--
PeteCresswell
| |
| Ulysses 2008-03-04, 1:25 pm |
|
"Warren Block" <wblock@wonkity.com> wrote in message
news:slrnfsp5b0.1opf.wblock@speedy.wonkity.com...
> You <you@shadow.orgs> wrote:
>
> Which might also be more efficient than a linear voltage regulator.
> Watts produced by physical effort are hard work.
>
> --
> Warren Block * Rapid City, South Dakota * USA
Or, instead of using the tire to drive the generator, make a little wind
generator, mount it on the handlebars, feed it into a charge controller and
run the light directly from some NiMh batteries being charged by the system.
25 mph out to be fast enough.
| |
|
|
"Ulysses" <eatmyspam@spamola.com/> wrote in message
> Or, instead of using the tire to drive the generator, make a little wind
> generator, mount it on the handlebars, feed it into a charge controller and
> run the light directly from some NiMh batteries being charged by the system.
> 25 mph out to be fast enough.
That'll get the girls.
| |
| (PeteCresswell) 2008-03-08, 5:25 pm |
| Per Martin Riddle:
> ________ | LM317 |
>HUB------------------|AC +|------+-------|VIN Vout|----+------3V
> | | | | | |
> | | C | ADJ | R
> | | 1 ---------- 1
> | | | | |
>HUB------------------|AC -|------+ +---------+
> -------- | | |
> | R C
> | 2 2
> | | |
> \-------------+---------/
> |
> GND
>C1 = 100Uf
>C2 = 1uf Optional
>R2 = 240
>R1 = 180 (calc 173)
>
>Vout = 2.916V
Got a bag full of little parts from Radio Shack this afternoon.
2 Final questions:
-----------------------------------------------------------
1) Do the watt-dissipating capabilities of R1 and R2 have tb
matched to the power that's coming out of the inverter?
Or is whatever's flowing through them relatively minor?
2) Am I correct in assuming that the absolute Ohm values
of R1 and R2 are not relevant: that it's the ratio of
the two that is important?
------------------------------------------------------------
--
PeteCresswell
| |
| Ulysses 2008-03-11, 8:25 pm |
|
"(PeteCresswell)" <x@y.Invalid> wrote in message
news:tg66t3l7tc7s8heln6e9plc2m3omucl0un@4ax.com...
> Per Martin Riddle:
>
>
> Got a bag full of little parts from Radio Shack this afternoon.
>
> 2 Final questions:
> -----------------------------------------------------------
> 1) Do the watt-dissipating capabilities of R1 and R2 have tb
> matched to the power that's coming out of the inverter?
>
> Or is whatever's flowing through them relatively minor?
>
> 2) Am I correct in assuming that the absolute Ohm values
> of R1 and R2 are not relevant: that it's the ratio of
> the two that is important?
What inverter? You mean voltage regulator? 1/4 watt resistors should be
just fine.
If the schematic is correct (probably is) then R1 is adjustable and you can
use it to adjust your output voltage. R2 is fixed. The capacitor values
look OK to me for what you are doing. If you should ever want to power some
electronics with this circuit then I'd go with a much bigger capacitor. I
don't have the schematic handy and the power supply I have in front of me
has some wierd surplus resistor with a third-world color code so I can't say
just what value it is but I have this particular one fixed at 4 volts. I
don't even remember what I was using it for. I guess that rectangle at the
AC input is the bridge rectifier. The LM317 requires a DC input and ground
is common.
> ------------------------------------------------------------
> --
> PeteCresswell
| |
| (PeteCresswell) 2008-03-11, 8:25 pm |
| Per Ulysses:
>What inverter? You mean voltage regulator? 1/4 watt resistors should be
>just fine.
I'm feeding it from an inverter hooked to an alternator.
>If the schematic is correct (probably is) then R1 is adjustable and you can
>use it to adjust your output voltage. R2 is fixed. The capacitor values
>look OK to me for what you are doing. If you should ever want to power some
>electronics with this circuit then I'd go with a much bigger capacitor. I
>don't have the schematic handy and the power supply I have in front of me
>has some wierd surplus resistor with a third-world color code so I can't say
>just what value it is but I have this particular one fixed at 4 volts. I
>don't even remember what I was using it for. I guess that rectangle at the
>AC input is the bridge rectifier. The LM317 requires a DC input and ground
>is common.
I hooked everything up twice: once with wire. Then a second time
on a "PC board" after it finally dawned on me that there had tb a
better way - and I'd managed to break the wiper wire off of the
variable resistor.
I'm getting current out of it, but the voltage is all over the
place - no apparent regulation.
First thing, I'll triple-check the wiring.
If that doesn't turn anything up, I'll remove the non-essential
components and try again.
And if that brings no joy, I'll assume that I toasted the LM317
with my ham-handed soldering technique and try replacing it.
--
PeteCresswell
| |
| Ulysses 2008-03-12, 5:25 pm |
|
"(PeteCresswell)" <x@y.Invalid> wrote in message
news:1n6et3tm8u2tb1r5j4sb91tsdbfl9o3avm@4ax.com...
> Per Ulysses:
>
> I'm feeding it from an inverter hooked to an alternator.
You lost me. I thought you were going to feed it with a bicycle alternator
and run it through a bridge rectifier. The input for the voltage regulator
needs to be DC. If you are using the inverter/alternator for test purposes
I suggest that a 12 volt battery would be a lot simpler. In that case you
would bypass the rectifer bridge and connect positive voltage directly to
pin #1.
>
can[color=darkred]
some[color=darkred]
I[color=darkred]
say[color=darkred]
the[color=darkred]
ground[color=darkred]
>
> I hooked everything up twice: once with wire. Then a second time
> on a "PC board" after it finally dawned on me that there had tb a
> better way - and I'd managed to break the wiper wire off of the
> variable resistor.
>
> I'm getting current out of it, but the voltage is all over the
> place - no apparent regulation.
>
> First thing, I'll triple-check the wiring.
Looking at the front of the LM317T pin #3 is on the left, #2 in the middle,
and #1 on the right. Looking at the block diagram on the back of Radio
Shack's blister pack pin #1 is on the left (Vin), pin #2 is on the right
(Vout), and pin #3 (ADJ) is in the middle at the bottom.
For starters is your input DC? Is the "voltage in" connected to pin #1? Is
"voltage out" connected to pin #2? Is R2 connected between pins 2 and 3?
Is your variable resistor connected between pin #3 and ground (minus)? If
you are using electrolyte capacitors check to make sure the stripe on the
can is connected to negative.
>
> If that doesn't turn anything up, I'll remove the non-essential
> components and try again.
>
> And if that brings no joy, I'll assume that I toasted the LM317
> with my ham-handed soldering technique and try replacing it.
> --
> PeteCresswell
| |
| (PeteCresswell) 2008-03-12, 5:25 pm |
| Per Ulysses:
>You lost me. I thought you were going to feed it with a bicycle alternator
>and run it through a bridge rectifier.
Mea culpa on the terminology. My grasp isn't that great to
begin with, and I've been coming down with some flu-like ailment
all week. Alternator ==> Bridge Rectifier, it is.
If my IQ were above room temperature when I wrote that, I'd be
surprised.
--
PeteCresswell
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