Easy Conversion of Puch headlight to bright LED

[rockethead26]

After seeing Gamebent's LED conversion of a Puch moped headlight here (a little down the page):

http://www.ratrodbikes.com/forum/viewtopic.php?f=6&t=51150&st=0&sk=t&sd=a&start=45

I decided to give it a try. I thought I would post here as a DIY project instead of in the Gallery.

I bought a Puch light and a pair of the 24 LED lamps that Gamebent used off eBay and waited. The Puch looked different than the one Gamebent used so I was a little concerned if it would work. The headlight arrived last week and indeed the housing is much shallower and built differently than Gamebent's. It was, however in great condition and would require no painting.





The inside was so small, that I was worried if I could fit a battery and switch inside.



I went to Fry's Electronics yesterday and bought a couple of small switches and a few other things so I was ready to give the conversion a shot when the bulbs arrived.

Good timing as the 24 LED bulbs arrived today. I jumped right on the project.



After spending an hour or so contemplating the situation, I decided to use one of the metal side mounts as the position for the switch since my plan was to only use one mounting hole on a bracket to mount to the bike.

I drilled out the threaded hole enough to allow the neck of the toggle to pass through and then ground down the outside metal collar until it popped off allowing me to enlarge the remaining hole enough to seat a nut to grab the neck of the toggle. It looked like this:



Here's the inside view of the switch with the package hangar cardboard in case anybody needs to know what switch I used. I couldn't find a simple tiny on/off toggle, so I had to settle for an on/off/on switch and just leave one side unconnected.



I was lucky that a 9-volt battery just fits inside the light at a slight angle. A thin layer of foam under the battery keeps enough pressure on it that it does not rattle around in the housing. The wiring was pretty straight forward.



The bulbs that I received had offset nubs to lock into the bulb area instead of opposing nubs like on the original bulb. A Dremel grinder took care of one of the nubs in a jiffy.



Since the outside of the switch/housing was a little ungainly



I had also bought one of these:



A little trimming of excess rubber and I had this:



A little silicone sealant and I think it looks better and seals the switch against moisture



I forgot to take a picture with the light on, but it is really bright!

I have to find a bracket that I like to mount it and then I'll put up a couple of final pictures.

This is the first time I've tried something like this and it was fun. Plus, I have a really bright light for my Straight 8 for about $30 total.

[Sorcerer]

Very slick and COOL. You may know I build "Rat " lights but Iam looking at tractor lights to overhaul also. Anyway your very crafty, keepit up.

Sorcerer

[B607]

Very good how to thread. I like! Gary

[rockethead26]

Here are some pics of the headlight mounted. I do need to make another bracket to place the light about 2" higher so it throws less light on the tire which creates a tire shadow about 3 feet out onto the road.

The bracket is simply a "T" support for wood joints I had laying around that already had perfect holes drilled. I cut off the "T" wings with a Dremel and then just bent the remaining straight strip to a little less than 90°. A trip to Lowes provided a 6-1 hex key bolt that fit the existing mount hole in the light. Easy!

I'm really happy with the performance of the light so far. It will start to illuminate reflective road signs about 75-100' out. The road itself is illuminated really well out to about 25' and reasonably well out to about 40'.

I think it mates with the bike perfectly.

[Saverio]

I tried this today and failed miserably. I had a regular on/off toggle switch and was able to get it to light up...with one problem...the batteries got HOT.
I started with just a housing, a toggle switch, and a $4 LED flashlight.
After reading tutorials, I decided it best to leave the heat sink on, and my set up was still getting way too hot for me to be comfortable. I decided to can the project, and start over if I get pointers on how to do it a "correct" way (your method seems to be exactly the light I was shooting for).

Do you notice yours getting hot? The flash light came with 3 AAA, so that's what I used. I'm curious how you knew to go with a 9V.

I'm a new guy here just trying to figure things out.

[rockethead26]

Saverio,

If the flsshlight you took the bulb from runs on 3 AAA batteries, then I'm not sure what's going on unless you have the wiring wrong, or the batteries the wrong way in the holder. I'm no electrical wiz, I had to Google how to wire my switch. Maybe another rodder can help here.

I went with a 9v battery on my 6v light because Gamebent was successful doing that. Evidently there is a voltage regulator in the bulb itself that only puts 6v to the bulb. The bulbs we used are replacement bulbs for car headlights. My light does not get hot, at least I haven't noticed it doing so.It has operated for up to 30 minutes so far.

My next light for my wife will be using the bulbs from the same flashlight you are using, so I am very curious how you solve this.

Maybe you could PM one of the guys who wrote one of the tutorials you followed.

Wish I could be more help.

[Saverio]

@rockethead

I'll find the post and email the guy to see if he knows why it would be heating up so bad. I knew something was not right because it was heating up just by being connected. It worked, so i'm fairly certain the connections were right. The only variable is that I used a two prong (on/off) swtich, and he used a 3 prong (just like the one you used).

He wired his light in this manner:
1. Wire from negative side of battery housing (the bottom, which is usually marked as so) to the 'off' position of his swtich.
2. Wire positive battery housing connection to 'on' position to swtich.
3. The third positon on the switch was used to for a connection he drilled into the flashlight housing, as a connection.

I'll be honest with you, after seeing yours, i've regained a little confidence and may go with your set up. It really does look great! I'm now going to scour the internet for a cheap moped headlight.

Please note that the LED bulbs and orientation of a flashlight are comepletely different than what you have pictured. I think this is because of the push button on/off switch the flashlights have. Maybe this is the smoking gun.....

[Wilcycle]

@rockethead
...... why it would be heating up so bad.............

1. Wire from negative side of battery housing (the bottom, which is usually marked as so) to the 'off' position of his swtich.
2. Wire positive battery housing connection to 'on' position to swtich.
3. The third positon on the switch was used to for a connection he drilled into the flashlight housing, as a connection.

Sounds like you have put the switch across the battery. Shorting the battery out would certainly make it heat up and not last very long.
It would also switch the light off, making it seem correct.

Try this..
1. Battery positive wire to one terminal of the switch.
2. Other terminal of switch wire to positive of Lamp/LED.
3. Battery negative wire to Lamp/LED negative. ((if the lamp is grounded thro the housing then the battery negative goes straight to the housing))

I am a technician electrician and a radio ham, so I know what I am meaning; now whether my words match my meaning is another matter
If not I will try and figure out how to add a wiring diagram to this thread.

Regards, Kevin

[Saverio]

Thanks Kevin!

[forrestsmith]

I did mine a year ago or so. Its such a natural fit for a bicycle.

Forrest

[Rooski]

Nice job, Rockethead!

How long does a fresh 9v Duracell last, if you just left it on and timed it?

[rockethead26]

Nice job, Rockethead!

How long does a fresh 9v Duracell last, if you just left it on and timed it?

Rooski,

I don't know yet. I have about 45 minutes on the current battery, but I didn't want to burn up a battery just for the test. I am curious how fast a 6v lamp will draw down a 9v battery.

Anyways, I'll always keep a spare in the tool pouch.

[gcrank1]

I know that the little pocket LED flashlight with only the 3 x 1.5v AAAs (nom. 4.5V peak) is way efficient and lasts a long, long time. With larger capacity, say 3 C or D cells it would probably be outrageous. These LEDs definitely are the way to go, but I think using a 3 LED light rather than the 9 LED is what I what to do.
+1 on on that two post switch; it is run on only one of the leads and doesnt matter which one.