Dynamo Lights complete

[rickson]

After receiving valuable advice from Martin, N4zou, and others, I finally completed my dynamo lights.

They consisted of a red tail light and 2 P4s in series using Martin's circuit number 9. Enclosures were 2 magnetic spice tin cans (magnet removed).

It took the better part of a day since I am a soldering newbie. Luckily, I had on hand soldering paste which made it a lot easier. I was able to fit all the capacitors in the front spice tin. The 2 leds were mounted to large double washers above the capacitors with a bolt to the back and another washer on the outsde. I mounted the front light to the right fork and the rear one to my seat post. I cut down the rear can since the red LED was mounted directly to the back. Amazingly, the circuit worked on the first try, although, the off switch didn't work. This led me to finding a short somewhere in the circuit. I used shoe goo to isolate the soldered wires, but it was hard to insulate everything.

I took a quick spin tonight. The lights have a very useful beam pattern, nice and wide with decent throw. The lenses are 5x20 and 5, 5x20 at the rear. They're not as intense as my L2D's hot spot, but the coverage is nice. I'll definitely be using these every day.

Building these was quite a learning experience. Here are some pics. Thanks for all the help.

 

[Swallow]

very good - you would appear to have a small child affixed to your bike hehe

 

[rickson]

Thanks, she's my dynamo load tester powered by jelly beans.

I really appreciate not having to load and unload my fenixes and dinotte all the time.

 

[Martin]

Thanks for sharing. And nice to see these spice cans in action.
Does the front heat sink actually run hot ?

You know, you'd soon have to upgrade your headlight to 6-LED to be on par with your horn.. Do you use this a lot ?

 

[rickson]

As to the front lights running hot, I don't know. The stars are glued to double washers with a bolt through the back. There is a direct metal path all the way from the stars to the bike's fork. I've been running them about 3 hours a day for the past week. People on the street comment on how bright that tail light is even in the daytime. The pictures below don't do justice to how bright these things actually are when on the road.

I'd be all over a quad front and double rear, but this setup is more than good enough for now. I don't use the horn much. It's far from the hoods and requires conscious effort to reach it. I also haven't felt much need to use it any way.

 

[Martin]

Just be aware that there's 50mm triple and quad Cree optics from DX that fit the spice cans perfectly, diameterwise.

 

[rickson]

It would be nice if DX described the beam patterns for their optics. It looks like most of these are spot. I really like the 5x20 or other elliptical type patterns.

 

[FrontRanger]

Enclosures were 2 magnetic spice tin cans (magnet removed).

Hi rickson,

Thanks for posting. If you're in the US, where did you get those spice tins? I recall looking for the Fackelmann ones that Martin mentioned long ago, but not being able to find them domestically. I was hoping to find something that would match nicely with one of those 50mm triple/quad optics.

Thanks.

 

[Martin]

.. in the US, where did you get those spice tins? ...

FrontRanger, look here or here or here or here or here or here...

I also updated the relevant page on my website by adding the word "mesh shaker".

 

[FrontRanger]

FrontRanger, look here or here or here or here or here or here...

I also updated the relevant page on my website by adding the word "mesh shaker".

Thanks, Martin! It wasn't that I couldn't find any spice tins / sugar shakers at all, so much as one that I knew would fit the optic. Strangely, none of my local stores sold them, and the flanges on those lids don't appear to have much margin. Since none of the many sites you listed (cheapest first, thank you) lists the size, I take it that the size must be a standard. That I did not know, so thank you.

CPF members are by far the most helpful bunch I've encountered on the web.

 

[rickson]

I used the kamenstein ones from pfaltzgraff. They're $2 a piece and have the glass window. I am sure that 50 mm optics would fit. They are not as sturdy as Martin's recommendations though but probably easier on the tools.

http://www.pfaltzgraff.com/ecomm/Itemdetail.asp?T1=F1226900

My wife was commenting tonight while following me that the lights are as bright as a lot of cars. As far as I know there are no light makers that make a dynamo tail light as bright as this one, so I think it pays to make your own.

 

[rickson]

Question for Martin. What happens if I add two more LEDs in series with what I already have, say in another can on the left fork without changing out any of the original capacitors? I am currently using the circuit 9 configuration with 4700 uF capacitors in parallel with the tail light and 2 front leds. There would then be 5 leds total, and I would add another 4700 uF capacitor to the additional 2 leds.

 

[FrontRanger]

I used the kamenstein ones from pfaltzgraff. They're $2 a piece and have the glass window. I am sure that 50 mm optics would fit. They are not as sturdy as Martin's recommendations though but probably easier on the tools.

http://www.pfaltzgraff.com/ecomm/Itemdetail.asp?T1=F1226900

Thanks, Rickson. I was hoping to find something smaller in diameter. Search string "round tin", which I hadn't tried before, led me to this promising-looking offering. At 2.375 inches (60 mm), it's large enough for a 50mm optic with a little room to spare. Perhaps a little deeper than necessary at 41 mm. Not only do they list the dimensions, but it already has clear plastic in the lid. It's very cheap, and shipping is quite reasonable.

Not surprisingly, they don't specify the optical efficiency of the plastic. At worst, it should be easy to cut out and replace.

 

[rickson]

Good find. 68 cents a piece is a steal. Optical efficiency, right....

 

[Martin]

..led me to this promising-looking offering...

Indeed, a great find. Lots of different shapes and sizes. Shipping to Europe doesn't look economical, though.

I prefer to have the can a little larger to avoid damage to the optics if the headlamp gets hit (like the bike falls over).

Question for Martin. What happens if I add two more LEDs in series with what I already have, say in another can on the left fork without changing out any of the original capacitors? I am currently using the circuit 9 configuration with 4700 uF capacitors in parallel with the tail light and 2 front leds. There would then be 5 leds total, and I would add another 4700 uF capacitor to the additional 2 leds.

That would work nicely. The capacitors across the LEDs (C1 equivalent) are uncritical. But - to get the optimum performance - you would want to use the appropriate values for C2, C3, C4, C5. More LEDs means the optimum capacitance for C2..C5 is smaller so it won't be difficult to do it mechanically. I have never optimized a 4x white + 1x red LED constellation but my feel is that you should use the C2..C5 capacitor values for 4 white LEDs.

 

[rickson]

According to your website, the only difference between 3 and 4 leds is C2 and C3, 1000 vs 470 uF. It may be difficult to reopen the can, since I have already glued it shut. Should I try adding the 2 additional LEDs anyway?

 

[Martin]

According to your website, the only difference between 3 and 4 leds is C2 and C3, 1000 vs 470 uF. It may be difficult to reopen the can, since I have already glued it shut. Should I try adding the 2 additional LEDs anyway?

So you mean C2..C5, the diodes and switch are all inside one can ?
You may add to the LED string (more LEDs in series), as long as you follow circuit 9. You may split C1 into multiple capacitors that connect across the LEDs so that you get some protection for the LEDs. You may NOT connect 2 additional LEDs in series with the AC input of the existing circuit.

 

[rickson]

Yes, C2...C5 are all in one can with the switch. I would splice into the + DC wire going to the tail light and connect two more LEDs in series with the whole string. I'm hesitant to reopen the can because it is a mess in there, although it works.

 

[mrbubbles]

Which red led did you use?

 

[Martin]

Yes, C2...C5 are all in one can with the switch. I would splice into the + DC wire going to the tail light and connect two more LEDs in series with the whole string. I'm hesitant to reopen the can because it is a mess in there, although it works.

If you do this it will work reliably but the performance suffers somewhat: Your power vs speed curve would not rise as fast as it could but the higher the speed, the less the difference.
When I need to seal a circuit I often use candle wax. This is relatively easy to remove with a hot air gun.