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Building a powerful/functional/cheap bicycle light

B

Borrall Wonnell

Jan 1, 1970
0
Hi all,

I am in the process of revising a design for DIY bicycle lights, and I
am looking for ideas/information.

My current system consists of a single/dual 20W/40W halogen light
setup, connected to a 12V battery. Since P = VI, each light should
draw approx. 1.67 A. With two lights connected in parallel, the trunk
line is subject to twice that amount of current (3.33 A).

For functionality, I have been using automotive quick-connects to
connect the lights to trunk line and from trunk line to battery. This
makes life a bit easier when I adapt the system for use as a
flashlight/emergency light system.

However, the quick-connects are cumbersome, as I need one for each
positive/negative connection. In other words, the trunk line requires
4 male connectors to hook up two lights (each light, in turn, requires
2 female connectors). This makes for a lot of connectors and
increased risk for mechanical failure over time (not to mention some
frustration).

I am considering options for an 'integrated' quick connector that
allows both +ve and -ve connections (such as an RCA jack). However, I
am concerned about how much current such a jack can accommodate. Size
is important...the smaller the connector, the better.

If anyone knows how much current these connectors can safely take (or
any alternate suggestions), please feel free to respond. If I'm in
the wrong group, please direct me elsewhere. If anyone is actually
interested in DIY lights, I'd be happy to share my design (costs about
$30 (single), $50 (dual), compared to $100-$200 for a commercially
available setup of similar power).

Cheers,
Dave
 
M

martin griffith

Jan 1, 1970
0
Hi all,

I am in the process of revising a design for DIY bicycle lights, and I
am looking for ideas/information.

My current system consists of a single/dual 20W/40W halogen light
setup, connected to a 12V battery. Since P = VI, each light should
draw approx. 1.67 A. With two lights connected in parallel, the trunk
line is subject to twice that amount of current (3.33 A).

For functionality, I have been using automotive quick-connects to
connect the lights to trunk line and from trunk line to battery. This
makes life a bit easier when I adapt the system for use as a
flashlight/emergency light system.

However, the quick-connects are cumbersome, as I need one for each
positive/negative connection. In other words, the trunk line requires
4 male connectors to hook up two lights (each light, in turn, requires
2 female connectors). This makes for a lot of connectors and
increased risk for mechanical failure over time (not to mention some
frustration).

I am considering options for an 'integrated' quick connector that
allows both +ve and -ve connections (such as an RCA jack). However, I
am concerned about how much current such a jack can accommodate. Size
is important...the smaller the connector, the better.

If anyone knows how much current these connectors can safely take (or
any alternate suggestions), please feel free to respond. If I'm in
the wrong group, please direct me elsewhere. If anyone is actually
interested in DIY lights, I'd be happy to share my design (costs about
$30 (single), $50 (dual), compared to $100-$200 for a commercially
available setup of similar power).

Cheers,
Dave
Dont really know what you mean by "quick connects", but when I used to
rewire my italian motorbikes, I just used Molex connectors, like the
1625 series, cheap and reliable, and tough, in line or chassis mount,
5 amp per contact or the Standard .093" range, up to 12A per contact
www.molex.com




martin

Serious error.
All shortcuts have disappeared.
Screen. Mind. Both are blank.
 
R

Roger Hamlett

Jan 1, 1970
0
Borrall Wonnell said:
Hi all,

I am in the process of revising a design for DIY bicycle lights, and I
am looking for ideas/information.

My current system consists of a single/dual 20W/40W halogen light
setup, connected to a 12V battery. Since P = VI, each light should
draw approx. 1.67 A. With two lights connected in parallel, the trunk
line is subject to twice that amount of current (3.33 A).

For functionality, I have been using automotive quick-connects to
connect the lights to trunk line and from trunk line to battery. This
makes life a bit easier when I adapt the system for use as a
flashlight/emergency light system.

However, the quick-connects are cumbersome, as I need one for each
positive/negative connection. In other words, the trunk line requires
4 male connectors to hook up two lights (each light, in turn, requires
2 female connectors). This makes for a lot of connectors and
increased risk for mechanical failure over time (not to mention some
frustration).

I am considering options for an 'integrated' quick connector that
allows both +ve and -ve connections (such as an RCA jack). However, I
am concerned about how much current such a jack can accommodate. Size
is important...the smaller the connector, the better.

If anyone knows how much current these connectors can safely take (or
any alternate suggestions), please feel free to respond. If I'm in
the wrong group, please direct me elsewhere. If anyone is actually
interested in DIY lights, I'd be happy to share my design (costs about
$30 (single), $50 (dual), compared to $100-$200 for a commercially
available setup of similar power).
Use high intensity LED's instead, and bring the power consumption down.
Reducing the current drawn, also simplifies the connectors (and reduces
the weight o battery that is needed...).
Jack plugs, are not a suitable connection, especially since the enviroment
will be quite harsh. Go to somebody like AMP's site, and you will have a
choice of connectors, including types where the pins are shielded from
water.

Best Wishes
 
K

Ken Smith

Jan 1, 1970
0
However, the quick-connects are cumbersome, as I need one for each
positive/negative connection. In other words, the trunk line requires
4 male connectors to hook up two lights (each light, in turn, requires
2 female connectors). This makes for a lot of connectors and
increased risk for mechanical failure over time (not to mention some
frustration).

Switchcraft makes connectors that are water resistant. You may want to
look at them.

I'd suggest using white LEDs as the lamp. They cost more but you may save
the difference on the reduced battery requirements.
 
R

Rich Grise

Jan 1, 1970
0
martin said:
....
Dont really know what you mean by "quick connects", but when I used to
rewire my italian motorbikes, I just used Molex connectors, like the
1625 series, cheap and reliable, and tough, in line or chassis mount,
5 amp per contact or the Standard .093" range, up to 12A per contact
www.molex.com
I know what "quick connects" are, and you should take the male ones
off the battery immediately and put the females there, with the males
at the light(s). Think metal-to-metal. :)

Then, I was going to suggest Molex too - heck, even a HDD power connector
would be good for 3A. And you can get 2- or 4- or more conductor
inline cable connectors at the auto parts store. And if you want to
get fancy-schmancy, you could even use inline fuse holders!

Good Luck!
Rich
 
N

Nico Coesel

Jan 1, 1970
0
Switchcraft makes connectors that are water resistant. You may want to
look at them.

I'd suggest using white LEDs as the lamp. They cost more but you may save
the difference on the reduced battery requirements.

LED's aren't very efficient either. I would try to use some kind of
fluorescent lamp.
 
B

Borrall Wonnell

Jan 1, 1970
0
Thanks for the constructive responses so far....I will take a look at
the suggested links (although I have already tried some molex
connectors).

Some additional comments:

1. Light choice. I ride forest trails at night, so a high-powered
beam is necessary to pick up speed and still avoid/manage roots,
stumps, and rocks. The dual 20W system (one flood, one spot) affords
me a clear view of all obstacles. I can get off-the-shelf halogen
bulbs/reflectors that do the job well. These are cheap and easily
replaceable. For road riding, even one 20W bulb is excessive. I
haven't found any commercially available LED solutions yet....nothing
that can throw enough light for my application. Using ultra-bright
LED's on a PCB is one thing, but incorporating a suitable reflector
makes this a daunting task for DIY. I love the prospect of the
reduced power consumption, though! Another light choice would be a
sodium arc lamp...these are available in low wattage sizes (8, 10,
13W) and typically throw as much light as an equivalent 30W halogen.
Unfortunately, bulbs are expensive ($100) and tend to only be
available in developers kits (minimum 5 bulbs). $$$$!!
Of course, if anyone has any links to a good LED source, I'm keeping
my mind open!!

2. Battery. At just under 4 lbs, the primary problem is additional
weight. At this point, the cost to go to a NiMH system or lithium
battery ($$$ + more $$$ for a proper charger) can't be justified. See
price list below...the battery cost is minimal.

3. Light housing. I have been using plumbing parts to date...with
proper selection, these have provided me with tough, compact,
water-tight lights. Actually, the lights are not quite waterproof
(i.e. you couldn't submerge them to a significant depth), but they
certainly hold up to the hardest of rainstorms or splash from puddles.


Here are the basic parts/prices for the system:
12V 20W halogen light: $5 (x 2)
Light housing: $5 (x 2)
12V, 4.5Ah SLA battery: $15
Switch/Fuse/Connectors: $10
Wire: pennies

So all told, about $40 - $50 CDN for parts.
Naturally, one needs tools to assemble (soldering iron) and a battery
charger ($10). Not bad for a durable, weather resistant, powerful
lighting system.

Cheers,
Dave
 
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