DIY LiPo lights.

[Kevin Mills]

I have one of these for my RC car which i never use. It is a LiPo battery 4s. In the RC world the Turnigy batteries are as far as i know the standard for quality:

Could this be used for a DIY bike light? I was thinking maybe i could buy just the light unit without the battery pack to save money?

If i used this with my helmet i would put the battery in my pack. If i did it on my handlebars i would mount the battery at the water bottle mount.

I have never used 2 lights in combination before so i’m not really sure which configuration would be best but I would use it in combination with a Bontrager 700r which i already own:

I am planning on buying a new Bontrager helmet in the next few weeks with my new bike. This helmet has the mount for the Bontrager ion 700r. I think this is a very neat solution:

Thoughts?

 

[Jeff Barber]

What kind of lamp do you have in mind? Obviously you’d also want to wire in a switch, and maybe a way to adjust the power (brightness). You’ll also want to waterproof the whole setup, and make it a neat package. Could be a fun project if you enjoy DiY, but probably not a good way to save money.

[Kevin Mills]

Thanks. I think you might have just talked me out of it. I just assumed the switch would be in the light? I’m thinking maybe LiPo would be problematic because you cannot fully discharge a LiPo battery. It might be dangerous.

[craZivn]

I had a similar aspiration, since I have plenty of rechargeable AA NiMH batteries on hand and wanted a cheap light. This is what I used: https://www.superbrightleds.com/moreinfo/led-light-pods/10w-mini-aux-2in-modular-led-off-road-work-light/1699/

It will operate over a very wide range of voltage (9-50 volts!) at a listed amperage of only .68 amps, so it will run off of darn near any battery pack for quite a while. I’m not 100% sure but if the minimum operating voltage of this light is 9v as stated, it should cut out before your battery becomes dangerously depleted.

All you would need is the light, and a plug to match up to the plug on your battery pack. The light pod comes with an appropriate connector that has pigtail wires so you’d need a basic soldering ability. You could wire in a switch for a couple extra bucks, or simply unplug the light to shut it off.

I ended up buying the light (60 degree version), a battery box with switch, and the appropriate pigtail connector for the barrel on the battery box. All-in with shipping I was under $50 and I can now use my excellent old Eneloop batteries for my excellent new light. Thinking about adding a second 30-degree-angle pod to complement the 60-degree one, but I’ll ride with this for a while and see if more light is worth it.

Two drawbacks: First off, I don’t know what average bike lights weigh and I didn’t weigh mine, but it’s no lightweight. It’s designed to be mounted on a truck or 4-wheeler, weight savings wasn’t a big consideration in it’s design.

Secondly, there’s no dimming option. This light is BRIGHT! The only simple option for dimming is to leave the pivot bolt loose enough so you can pitch the light toward the ground if you approach someone. There is also the option of wiring in a switch box to reduce the amperage but that’s way more effort than I was ready to put forth.

I found this thread because it was mentioned in a recent Singletracks podcast that you can’t use an R/C battery pack to rig up a light on the cheap. I’m just here to set the record straight and say that yes, yes indeed you can!

Ivan

[Kevin Mills]

I agree, it’s definitely possible: http://www.instructables.com/id/RC-Battery-Power-for-Bike-Lighting/

To be honest i can’t be bothered with all the messing around. There is too much i already have to worry about with prep and maintenance. Worrying about powermeters, computers, lights, clothing and everything else is getting a bit much. I am trying to adopt a more minimalist approach to my riding.

I am lucky enough that i live in the desert where the night sky is almost always crystal clear which allows me to use minimalist lighting effectively. My Bontrager Ion 700r should be more than enough.

[BBelfield]

They work awesome and are cheap. Get chinese lipos for a third of the price of turnigy and solder in a low volatage cutoff. Profit!

 

[Xmtnbke]

With super bright LED lights designed for the rough use on a MTB or helmet, you’d be money ahead just buying a charger and rechargeable bats. I understand wanting to put the LiPo to use, but sometimes using what you have on hand isn’t always the best option. Plus you gotta love the flasher sequences built right into some of these new lights.

[clipless]

I’m using 3 cell turnigy lipos to power my homebuilt lights.  2 cree xpg2’s on my helmet and 2 cree xml2’s on my bars.  You need to make sure your led driver can handle the input voltage, and step it down to what the leds require.  I’m using a buckpuck for the helmet, and a taskled b-flex for the bars.  The b-flex is an awesome driver, programmable high, medium and low settings and cutoff voltage (and much more).  You’d probably need to build your own light and use a good driver.  I doubt commercially made lights will handle the 16.8 boots your fully charged 4s pack will pump out.  Check out the d.i.y. lights forum on mtbr.  You don’t need fancy tools, although it helps.  I built my with barstock aluminum and a tablesaw.  Good luck!

 

 

 

 

 

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