Hi all
I’m in the process of building a couple of new bike lights for MTB use and would appreciate a little a little advice before I order the last bits.
I’m making a new bar and helmet light and am looking to use 2 x XHP70 for the bars. I’m also trying to use a few bits I have in old lights so:
Can I use 2 x XHP70 (12v) in series, driven by a HBFlex @ 2.5a off a 15v 5.2aH battery?
I’m not looking for huge run-times as my rides are restricted to 2-3 hours max with most of that time spent going up with only short, fast downhill sections. Will be using some Ledil IRIS lenses but may look to change them if they don’t work well.
Here’s the casing I’ve made:
That housing is better looking than my, dont think I can say that. Lets just say I agree with will. It almost looks to good to do anything else with. One thing I will mention that even running XHP70’s at 1.5 amps, over time they will get hot. Can you post up a build thread on your light? Pictures of the machining would be orsm as well.
One thing I’ve tried to do is mount the driver on the bottom of the housing so it will get very good air-flow to cool the driver which will, hopefully, help with keeping the LED’s cool.
Here’s a few more pics:
Luckily, I work as a CNC programmer so have access to some state of the art 5 axis machines which makes it much easier to knock up housings
You could also mount the driver separately from the housing, this way even if the light gets scorching hot the driver will still work perfectly. And maybe mount a small DC fan on the bottom to ensure safe temperature when stationary. The HBflex is very efficient so I don’t think it will produce too much heat.
Thanks :+1:
Tried to get the weight down as much as possible on this one as it’s to replace an old 7-up (2 x 3 + 1) XM-L I made with adjustable side pods.
That one was a bulky 340g’s, the new one should be just over 200g
There’s a good reason not to do that with the TaskLED drivers. They have built in thermal throttling capability, so ideally you want the driver to experience the same heat as the LEDs so that it can be programmed to step down at whatever temperature you set. Depending on the light I usually set this at 70 degrees C.
Housing looks really nice! The HBFlex should be fine for that application since it can drive an LED load of up to 3A. Because it is a boost driver you’ll be drawing something in the 5-6A range from your battery pack so think about keeping the battery cable as short as possible and make sure to use cables and plugs rated for that kind of current to avoid voltage sag related issues.
Thanks mate
Battery cable will be approx 6” long and is professionally built by mtb batteries. For the other bits I’ve got some cable I pulled out of an old AV amp that seems to measure up about 16AWG (1.2mm Ø). Would that be suitable?
16AWG is pretty thick so should be more than good enough. Wire gauge more becomes more of a concern the longer the cable, so with only a 6” long battery cable this shouldn’t be an issue. Assuming the battery is a LiPo pack of some sort, voltage sag shouldn’t be a concern either. What about that connector, is it rated to handle say 6A?
Looking forward to seeing the built up light and of course the requisite beam shots!
