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From: Snag on 7 Jun 2010 19:38
I've had comp er comments about my brake lights not being bright enough
.... so I thought I'd try my hand at fabricating an LED unit . Wow , those
things want a really narrow range of voltages ! So I've got a hundred (less
7 , how do ya think I found out how finicky they are ?) of these wide angle
"top hat" red LED's that want between 1.8 and 2.2 volts, and I wanna use
them to make a light panel to go in my tourpak lid . Actually, to replace
the bulb that's in the fixture now . I'm thinkin' (see the steam ?) that I
can use a voltage regulator to drop the supply volts to 10 and wire them in
series ckts of 5 each , for a nominal voltage drop of 2 volts each . I'll
need 2 regs if I want to do taillight too ... it'll have to be breadboarded
inside the fixture , but there's plenty of room in there .
Insights , oversights , am I crazy for wanting to do this ? I'll probably
run about 40 bulbs (@20 ma/ea , IIRC) for brake and 10 for runnin' lights ,
reckon I'll need a heatsink for the brakes ?
--
Snag
"90 FLHTCU "Strider"
'39 WLDD "PopCycle"
BS 132/SENS/DOF


From: Greasy Rider on 7 Jun 2010 20:13
On 6/7/2010 19:38, Snag wrote:
> I've had comp er comments about my brake lights not being bright enough
> ... so I thought I'd try my hand at fabricating an LED unit . Wow , those
> things want a really narrow range of voltages ! So I've got a hundred (less
> 7 , how do ya think I found out how finicky they are ?) of these wide angle
> "top hat" red LED's that want between 1.8 and 2.2 volts, and I wanna use
> them to make a light panel to go in my tourpak lid . Actually, to replace
> the bulb that's in the fixture now . I'm thinkin' (see the steam ?) that I
> can use a voltage regulator to drop the supply volts to 10 and wire them in
> series ckts of 5 each , for a nominal voltage drop of 2 volts each . I'll
> need 2 regs if I want to do taillight too ... it'll have to be breadboarded
> inside the fixture , but there's plenty of room in there .
> Insights , oversights , am I crazy for wanting to do this ? I'll probably
> run about 40 bulbs (@20 ma/ea , IIRC) for brake and 10 for runnin' lights ,
> reckon I'll need a heatsink for the brakes ?

My camera is on the fritz so I can't supply you with photo evidence. I
purchased a led bar (offered in red or yellow) from JC Whitney for $12.
Bright as hell and probably cheaper than you can make one. Search "LED"
or "LED brake" or "LED Strips" if interested. All sorts of light
assemblies that may be gooder. Just don't give them your real e-mail or
you'll be sorry!

I would put the standard disclaimer here but I am a major stockholder in
JC Whitney and we do appreciate your business! :)


Greasy
From: Windstream on 7 Jun 2010 21:12
Okay, each LED draws about 20ma of current and needs 2 volts. You need to
use a resistor to drop the voltage down 10 volts. 40 bulbs, wired in
parallel, at 20ma each comes to 800ma. Now the current limiting resistor
has across it 10 volts and 800 ma. The equation for the resistor is R=E/I
or 10/.8 gives you 12.5 ohms. Power across the resistor is P=IE or .8x10 =
1 watt. So you need a 12 ohm resistor capable of 2 watts (double the load
for good measure). Connect this in series with the 40 LED's connected in
parallel. It's a lot of work to make this gismo, I thought about it, but it
was easier to buy the bulb already made.

RD
81' FLH
'86 FLHTC Liberty
'08 FLHTCUI (with factory LED brakelight)

"Greasy Rider" <greasyrider(a)noway.com> wrote in message
news:CWfPn.146673$jt.98054(a)newsfe04.iad...
> On 6/7/2010 19:38, Snag wrote:
>> I've had comp er comments about my brake lights not being bright
>> enough
>> ... so I thought I'd try my hand at fabricating an LED unit . Wow , those
>> things want a really narrow range of voltages ! So I've got a hundred
>> (less
>> 7 , how do ya think I found out how finicky they are ?) of these wide
>> angle
>> "top hat" red LED's that want between 1.8 and 2.2 volts, and I wanna use
>> them to make a light panel to go in my tourpak lid . Actually, to replace
>> the bulb that's in the fixture now . I'm thinkin' (see the steam ?) that
>> I
>> can use a voltage regulator to drop the supply volts to 10 and wire them
>> in
>> series ckts of 5 each , for a nominal voltage drop of 2 volts each . I'll
>> need 2 regs if I want to do taillight too ... it'll have to be
>> breadboarded
>> inside the fixture , but there's plenty of room in there .
>> Insights , oversights , am I crazy for wanting to do this ? I'll
>> probably
>> run about 40 bulbs (@20 ma/ea , IIRC) for brake and 10 for runnin' lights
>> ,
>> reckon I'll need a heatsink for the brakes ?
>
> My camera is on the fritz so I can't supply you with photo evidence. I
> purchased a led bar (offered in red or yellow) from JC Whitney for $12.
> Bright as hell and probably cheaper than you can make one. Search "LED" or
> "LED brake" or "LED Strips" if interested. All sorts of light assemblies
> that may be gooder. Just don't give them your real e-mail or you'll be
> sorry!
>
> I would put the standard disclaimer here but I am a major stockholder in
> JC Whitney and we do appreciate your business! :)
>
>
> Greasy


From: Snag on 7 Jun 2010 22:12
Windstream wrote:
> Okay, each LED draws about 20ma of current and needs 2 volts. You
> need to use a resistor to drop the voltage down 10 volts.

Nope , they make solid state regulator units . Got two of 'em on the PCB
of the DRO I built from a kit . One does +1.5v for chinese scales , the
other +5v for quadrature scales

>40 bulbs,
> wired in parallel, at 20ma each comes to 800ma.

Lessee here , current is common in series , volts in parallet . So I'm
going to be pulling 20 ma per string of 5 LED's , and 8 strings for brakes .
Sounds more like 160 ma ... and 20 ma for tail lights .

And let's not forget ELI the ICE man ...

> Now the current
> limiting resistor has across it 10 volts and 800 ma. The equation
> for the resistor is R=E/I or 10/.8 gives you 12.5 ohms. Power across
> the resistor is P=IE or .8x10 = 1 watt. So you need a 12 ohm
> resistor capable of 2 watts (double the load for good measure). Connect
> this in series with the 40 LED's connected in parallel. It's
> a lot of work to make this gismo, I thought about it, but it was
> easier to buy the bulb already made.

Well , the thing is , I'm kind of a do-it-myself kinda guy . I got some
clear .125" acrylic , a drill bit the right size for the lights , and a
soldering iron . Oh , and a (small) machine shop in my back yard - including
aluminum foundry equipment .
Oh , and Greasy - the lights cost me like 5 bucks a hundred - plus there's
the "challemge factor" . Kinda like a second cousin to the "Hole ma beer an'
wartch this" school of thought .
--
Snag
"90 FLHTCU "Strider"
'39 WLDD "PopCycle"
BS 132/SENS/DOF


>
> RD
> 81' FLH
> '86 FLHTC Liberty
> '08 FLHTCUI (with factory LED brakelight)
>
> "Greasy Rider" <greasyrider(a)noway.com> wrote in message
> news:CWfPn.146673$jt.98054(a)newsfe04.iad...
>> On 6/7/2010 19:38, Snag wrote:
>>> I've had comp er comments about my brake lights not being bright
>>> enough
>>> ... so I thought I'd try my hand at fabricating an LED unit . Wow ,
>>> those things want a really narrow range of voltages ! So I've got a
>>> hundred (less
>>> 7 , how do ya think I found out how finicky they are ?) of these
>>> wide angle
>>> "top hat" red LED's that want between 1.8 and 2.2 volts, and I
>>> wanna use them to make a light panel to go in my tourpak lid .
>>> Actually, to replace the bulb that's in the fixture now . I'm
>>> thinkin' (see the steam ?) that I
>>> can use a voltage regulator to drop the supply volts to 10 and wire
>>> them in
>>> series ckts of 5 each , for a nominal voltage drop of 2 volts each
>>> . I'll need 2 regs if I want to do taillight too ... it'll have to
>>> be breadboarded
>>> inside the fixture , but there's plenty of room in there .
>>> Insights , oversights , am I crazy for wanting to do this ? I'll
>>> probably
>>> run about 40 bulbs (@20 ma/ea , IIRC) for brake and 10 for runnin'
>>> lights ,
>>> reckon I'll need a heatsink for the brakes ?
>>
>> My camera is on the fritz so I can't supply you with photo evidence.
>> I purchased a led bar (offered in red or yellow) from JC Whitney for
>> $12. Bright as hell and probably cheaper than you can make one.
>> Search "LED" or "LED brake" or "LED Strips" if interested. All sorts
>> of light assemblies that may be gooder. Just don't give them your
>> real e-mail or you'll be sorry!
>>
>> I would put the standard disclaimer here but I am a major
>> stockholder in JC Whitney and we do appreciate your business! :)
>>
>>
>> Greasy





From: Old Crow on 8 Jun 2010 06:07
"Snag" <snag_one(a)comcast.net> wrote in message
news:0qfPn.140038$0M5.112264(a)newsfe07.iad...
> I've had comp er comments about my brake lights not being bright enough
> ... so I thought I'd try my hand at fabricating an LED unit . Wow , those
> things want a really narrow range of voltages ! So I've got a hundred
> (less 7 , how do ya think I found out how finicky they are ?) of these
> wide angle "top hat" red LED's that want between 1.8 and 2.2 volts, and I
> wanna use them to make a light panel to go in my tourpak lid . Actually,
> to replace the bulb that's in the fixture now . I'm thinkin' (see the
> steam ?) that I can use a voltage regulator to drop the supply volts to 10
> and wire them in series ckts of 5 each , for a nominal voltage drop of 2
> volts each . I'll need 2 regs if I want to do taillight too ... it'll have
> to be breadboarded inside the fixture , but there's plenty of room in
> there .
> Insights , oversights , am I crazy for wanting to do this ? I'll probably
> run about 40 bulbs (@20 ma/ea , IIRC) for brake and 10 for runnin' lights
> , reckon I'll need a heatsink for the brakes ?
> --
> Snag
> "90 FLHTCU "Strider"
> '39 WLDD "PopCycle"
> BS 132/SENS/DOF
>


I noticed Sat when we followed you to lunch that you either weren't using
your turn signals, or they aren't very bright either. Have you checked the
grounds back to the lights? Even Dave's tail light is brighter than yours.

--
Old Crow
'82 FLTC(P) 92"
'87 FLTC
'61 F-100 302/C-6
BS#133, SENS, TOMKAT, SLOB#13, MAMBM


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