Following on from the decent road bike light thread, I thought I’d share the results of my recent tinkering. I converted my old halogens last year but as my commute now involves several miles of unlit country road I decided some upgrades were in order, and in particular I wanted a remote on one of the lights.

I decided to switch to the bflex driver. This is even more of a squeeze than the black cat driver, but can be made to fit if you remove the switch and bend the connectors on the back of the power socket. The bflex driver has a pad on it for heatsinking. I made a small cube of aluminium and used some thermal transfer adhesive to attach the PCB to the cube, and the cube to the heatsink:

As well as giving the driver some heatsinking, it means that the driver’s thermal cut-out detection should accurately detect the LED temperature.

For the remote, I wanted something discrete and easy to access. My 105 levers are Flightdeck compatible, meaning they have a little nipple on the inside of the hood that’s designed to operate a switch. The real Flightdeck hardware is stupidly expensive, but I managed to bodge a miniature switch into the flight deck blanking panel so that it sits exactly behind the nipple.

The wiring and the socket are hidden under the handle bar tape.

The end result works very nicely. I’m running the bflex driver at 1000mA, and use the switch to toggle between “L1” (out of 5) and full power.

With the thermal cut-off set to 70 degrees, it’ll run for a few minutes stationary indoors before cutting in, at which point the case is at 50 degrees. In real use, I’ve never had it cut in, and the case barely gets above luke warm.

The other light is running at 870mA with a mid optic, and pointed well down. The bflex light is pretty much horizontal with a spot optic. The “dipped” light is enough to cycle by, but it’s not exactly relaxing. Both together gives loads of light well into the distance and means you can really relax, even at well over 20mph.

With the bflex light on minimum, the combination doesn’t seem to cause any offence to oncoming drivers, but on full it’s bright enough that drivers can see you coming round the next corner and dip their lights before they even see you.

That my dear Sir is very nicely done, I’m impressed.

Hats off to you

Indeed, a most very fine fettle I might add!

I’m lovin the utilisation of the ‘in situ’ flight deck’ gubbins!

I dont understand what your bars are like? The levers seem to be right at the end, and in the last pic they seem to go up? Can you show a pic of the complete bars. I am loving the use of the ‘button’ Top work!

Here’s an old picture of the bike. They’re Profile Airwing bars:

Nice! I thought the Bflex driver was bigger than that. It looks quite dinky in your pic of it taped to the back of the heatsink.

How easy did you find the Bflex to set-up. It looks like a bit of a pain with many button presses and reading of coded light flashes….?

I have a Bflex driver sitting at home waiting to be wired up to a Lumi LED package, Which component is it that you need to mount to the heat sink? I have been putting off building it as i thought 750mA may not be quite enough and 1000mA would be overkill and get everything to hot!

Is 70 degres a preset value or could this be reduced? I was kind of thinking 60 degrees my be a better value but have no reasoning for this.

you can set 60deg or even 50 IIRC.
the bflex is a little faffy to program but you’re only likely to do it a few times at most.

It is pretty small, but it’s depth that’s the problem fitting it into the can. It does have to be mounted off-centre in order to clear the bolt in the can.

The driver is actually pretty easy to set up – it’s as easy as it could be given the input method. Basically, you click the button N times for the menu option you want, and the LED flashes to confirm each click. Then press and hold to select that option, then you click to choose the value for that menu option, with the current setting being indicated by the brightness. If you lose track of the current setting, you just cycle round until it goes dim again. Then a long press to confirm.

It has to be said, Mrs pdw quite didn’t share in my excitement at the prospect of a bike light that needed a 27 page manual to operate 😀

Which component is it that you need to mount to the heat sink?

It’s the large pad on the PCB:

Ok cheers for that, will have a look when i get home. My PCB is slightly diferent as it is a BFlex rather than the newer B2Flex. I have some Arctic Aluminium adhesive stuff so will just need to find some Aluminium to mount onto the pad then onto the heatsink of the LED package.