Mountain Bike LED Light Bar W/ Makita Battery




With summer soon approaching in Australia, the appeal to ride in the cool of the night is evident. Although the cost of a decent bike light is a minimum of $200-300. This guide will show you how to develop a mountain bike light utilising a small LED light bar (usually used for 4WD's) and a cordless drill battery for under $100.

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Step 1: Materials

For this project, you will need:

  • Small LED Light Bar - preferably with spot and flood light combination
    For this project I used a STEDI ST3501 6.5 inch 30W super slim LED light bar (as pictured) for $60
  • Makita battery terminal: part number 643838-6
  • 3D printed battery mount (see attached)
    For this project I adapted a design by GPlatek:
    I added two holes 64mm apart so that the battery mount could be attached to where the drink bottle holder would normally sit.
  • Cable ties, female spade connector, M5 0.8mm spaced 20mm bolts

Step 2: Assembly

  • File back the 3D printed battery mount to enable the battery terminal to be inserted - it will be a tight fit
  • Attach the wires from the light bar to female spade connectors and crimp/solder together and then connect to the male spade connectors on the terminal (pos and neg terminals specific)
  • Mount the assembly onto the bike using the bolts
  • Using cable ties, tidy the cables to the underneath of the bike
  • Mount the light bar to the handlebars, options include:
    • Use the standard brackets that come with the light bar, using thick cable ties and a rubber strip to protect paint
    • Purchase a light bar tube clamp style bracket (as pictured) - measure the thickness of your handlebars prior
  • Additional features you may wish to include:
    • On/Off switch
    • Dimmer switch

Step 3: Test and Enjoy

I found that a 1.5 amp hour 18V Makita battery powered my 6.5" light bar for almost 2 hours before I noticed dimming.

You may have a different brand of drill battery that you wish to use and I am sure there are plenty of other 3D printing designs out there which you can adapt to suit your needs.




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    11 Discussions


    Question 1 year ago on Step 2

    Have you got any photos of it on a track so we can see the spread of the beam ?


    Question 1 year ago

    This looks awesome, would love to get one of those lightbars on my electric bike, but where could I get the handlebar mounts that attach the lightbar, I've looked at the exact lightbar you have but it doesn't come with it. I also had a look at aliexpress and ebay but still couldn't find those handlebar mounts, any chance you could give me a link to where I could buy them, thanks


    1 year ago

    To everyone who is requesting that I print them a mount and send to them. Please note that I have included the 3D model file in the Instructable. All you have to do is download it, take it to your local 3D printer store or search online and get them to print it it for you. You may need to adjust the mounting holes to suit with a drill.


    1 year ago

    Any chance you could print one for me? I am willing to pay for shipping + materials etc


    2 years ago

    I guess you might want to add in here that this kind of light is not for use on a road, of any sort... there are some of these kinds out there!-)

    3 replies

    Reply 2 years ago

    in most jurisdictions in the US there are no restrictions on the use of such lights on streets and highway, within common sense. (i.e; use spot not flood pattern, aimed below 25", and not above the output of equivilent DOT approved lighting.) I have no problems riding with a lighting system with 5 cree xm-ls, that is probably consistent with the light in this instructible.

    IIRC Germany however does have strict regulations regarding dispersion patterns and output and other countries probably do as well.

    All that said there is a limit to how much light to take on the street OR trail before you become offensive to others and they do not want to ask you to go on group rides any more! (Particularly with helmet mount)


    Reply 2 years ago

    Thank you all for your comments. This project was never intended for use on the road, only trails. Where I live most cyclists are conscientious and mindful of those around them, both on the road and on the trail. You just need to use some commonsense. I'd like to have as much light as I can get at night on the trails so I don't fall off, hit another cyclist or hit a kangaroo (things we have to deal with in Aus), but at the same time if there is a cyclist coming the other way, slow down, turn off or dim your light and be respectful to others.

    I don't feel that we need to 'limit' the amount of light you're putting out, just be conscientious to others. I also have a small $20 eBay light which I use when I'm on the road between the trail and home, it is not offensive to motorists but still lets them know where I am.


    Reply 2 years ago

    is there any chance of you shipping 2 of those battery mounts up to Edmonton Alberta Canada?


    2 years ago

    This is a cool project, if you have not already you should post it over at MTBR.

    Several years ago I bought some Makita 18V battery adapters for this
    exact purpose, and they work great. However the Makita batteries had a
    bad habit of bricking themselves even though the cells were fine (they
    were too smart for their own good). That said they worked great when
    they did.

    Some things I added to mine were some Hirose HR30 or
    Switchcraft EN3 series connectors (depending on the pins I was using and
    the current required). I used the panel mount male connectors on my
    lights (with the optional covers), and ran a cable with an inline female
    connector from the battery pack / adapter (better to use female on the
    battery connected part I think so no pins are sticking out to possibly
    short something). With the 3d printed adapters it would seem trivial to add some holes suitable for panel mount connectors or a cable gland for water resistant set up.


    This is great. I like how you can pretty easily customize the light design to fit any kind of bike that you might have.