A couple of days ago I decided that the light of my push-bike was not bright enough. After looking at the prices for better lights (i.e. at least 20 Watts halogen) in a catalog, I was convinced that building my own would be the way to go.
*) 20W, 8 degree halogen spot (5 CHF)
*) rubber pipe coupling(13 CHF)
*) PP pipe plug (1 CHF)
*) lead acid gel cell (48 CHF)
*) a couple of cables
*) a aluminium plate
*) a switch
which I filched from the lab, therefore free.
All in all 67 CHF, or about 40 Euros.
A note about the batterie: I got myself a whopping 7 amphours cell, weighting in at about 2.6 kg. This should give me about 3.5 to 4 hours of light. (20W @ 12V draw 1.67A, and 7/1.6=4.2h, remove 20% for low efficiency)
First I drilled a coupe of holes in the aluminium-plate - it will be mounted on the bike-frame, where the cup-holder thingie normally sits. I also drilled two holes in the end-cap, for the switch and the cables.
The halogen spot, was connected to the cables via a cable-connector (no clue what it is properly called - those things electricians use to connect mains-cables). This has the advantage that you can change the spot easily - to get one with a wider angle, for example. Or a 50W bulb. Which would still give me more then an hour of light. Hmmmm...
The spot and the end-cap fit perfectly into the coupling, which can be tightened up so they sit, well, tight I guess.
Then I mounted the whole thing in my bike with a couple of cable-binders. Which is ugly. But hey, light! Bright! Shiny! Also, nobody will want to steal my bike now!
I'll probably tinker a bit with the mounting of the battery tomorrow (waterproofing comes to mind), and I might build a nicer enclosure for the light at some point (aluminium tubing maybe?), but I am pretty happy with it. Now I need only a bit of darkness...
1 week ago