Recycling a dynamo light by packing it into a rear fender reflector

A gigantic catch-all for Randonneuring (Audax), Bike-packing (Touring), and Commuting with or without E-bikes!
Post Reply
Posts: 3
Joined: Fri Sep 20, 2019 4:48 pm

by wildtangent1

#Alternate title: "What to do with your old Seculite Plus 2 if the plastic back has fallen off/cracked."

B&M (Busch & Müller) sell rear lights with standlight functionality ("Seculite plus 2") for about $50. Kind of a pain if you lose one. They happen to be our city's bike share scheme's rear taillight of choice. (This is relevant, I swear).

Album of images:

Weight figures included in the images for weight weenie commuters (there are dozens of us, I say! Dozens!) For those who are lurking, it's 16g as a reflector, and ~29g without. Maybe you can file it a little, or just glue and no blu-tak, and so on to lighten it up further.

The plastic Image outer lens occasionally gets knocked off. Probably by accident, as it protrudes a bit (a few CM past the intended design, but that's a decision that was mandated by the city's contract after the moulds for the fenders got put in), but also possibly just due to vandals being vandals.

It's actually tragic that it's so easy for that to happen, because when the plastic falls off of them, then the bike share mechanics have to swap it for a whole new unit, per policy (if it snapped badly, then a new bit of plastic cover won't go in, and B&M/the city apparently aren't comfortable with 'unlicensed repairs' being performed by 'unlicensed' people. Gotta love bureaucracy. Honestly I think they're just happy to sell more units.)

I'm friends with the mechanics and had them keep some of the units that had snapped off for me. Now, I considered 3D printing new unit lenses and putting them up on ebay or something as 'refurbished,' but that's energy inefficient and also I doubted it'd be reliable. So I had a bunch of these and no clue wtf to do with them.

Now, I've been commuting for a long time. Lights are one of the bugbears of riding.

I've had battery lights get either stolen, ripped off, of otherwise yanked clean free by thieves, and some lights get smashed up by...well, possibly it was just clumsy people, or yeah, vandals. But reflectors, even fender-reflectors, have always been left pretty well alone for some reason.

So I looked at the one on the the PapillionaireImage my friend rides, and realised "hey, if it's hollow, this old rear light might fit in there." I had to remove the screws, add a bit of bluetack/glue to keep it from bouncing around the interior, hand-drilled a little hole in the back for the wires, and now they have a discrete rear light that matches the original look of the bike. It works as a reflector even if 'something goes wrong.'

Apparently these exact reflectors are for sale on aliexpress for like $2. They mount directly on fenders. I really didn't want to jack her reflector up on a theory, so I ordered one, and sure enough it fits in there snugly.

These can mount on things other than fenders (say, a rear pannier rack).
Fancy-looking ones get battered, a lot. This looks like a $2 reflector.
Easy to do. Lots of them on-hand as I was lucky.
Low-weight, doesn't eliminate Reflector as a 'backup.' So, 'full functionality,' but modestly lighter weight.

Takes a TINY bit of know-how.
No "off" switch. I'm gonna need to scrounge up a headlight that's got one, and wire it through that, or else the constant drag might get annoying.
Not everyone has a bike share scheme using this particular tail light. I'm sure there are some other tail lights in use in your city's bike scheme, and they'll probably work just fine. General advice: find out where they are being serviced, lots of parts get chucked out well before they're "bad." Even then, a lot can be salvaged. Make friends.
Likely, you're going to need to order this or some other kind of reflector. Thankfully they're like, $2.
Needs Dynamo Hub or Dynamo to work. (There are some very lightweight dynamos now that are very efficient, such as VELOGICAL, which comes in at 75g.)
Not technically "net zero" (if you care) as you're still ordering a bit of cheap plastic, but it's better than the unit going into the landfill or being worn out prematurely by exposure to the elements.

Other notes:
These particular units also include a capacitor for "standlight" functionality (stays lit when waiting at a light). Downside: This adds weight.

by Weenie

Visit Online Retailer for HighEnd cycling components
Great Prices ✓    Broad Selection ✓    Worldwide Delivery ✓

User avatar
Posts: 122
Joined: Fri Dec 04, 2020 1:25 am

by bobrayner

Great work!
Sent from my computer using an internet browser.

Post Reply