Grin Technologies - DC-DC Ebike Lighting System

By: Ebike  09-12-2011
Keywords: Battery

DC-DC Ebike Lighting System

Electric bikes have large batteries that can in principle power lighting systems and accessories with energy to spare. But these ebike batteries range in voltage from 24V up to 72V, while most bike lights and accessories are made to run off 6V or 12V. At GRIN we've solved this by producing our own line of lighting components to run off a super wide input voltage for direct connection to any ebike battery pack, no separate voltage converter required. We also make small and rugged stand alone DC-DC converters with 5, 6, and 12V outputs for running 3rd party accessories.

Cycle Lumenator (15-100V input range)

The Cycle Lumenator is our brightest light by far. With four Cree XP-G LEDs driven at 750mA, this device puts out a stunning 1000 lumens of light. We designed it for people who want to ride at night on the same footing as cars, motorbikes, and other vehicles on the road. The beam angle is wider than most bike lights which tend to have a sharp focus to a single spot, so the Lumenator will brighten the entire terrain ahead of you, not just a small circle on the pavement.

The latest Cycle Lumenator model has multiple brightness levels but notice that the Cycle Lumenator at full brightness can be overwhelming to oncoming traffic on dimly lit separated paths. Care should be taken to either reduce the brightness via the remote button or angle the light sharply down when riding in friendly situations to not offend approaching cyclists and pedestrians. The smaller (1 watt range) LED light is a good alternative for being seen on bike paths, parks, and other places where people rather than vehicles are present and more subtlety is required.

Cycle Lumenator Features

  • Powered straight from Ebike Battery
  • Four Cree XP-G LEDs (some of the highest lm/W available)
  • Rainproof Metal Housing with Plastic Mounting Equipment
  • On/Off Button
  • Adjustable Handlebar Bracket
  • Made in Canada (Circuits + Assembly) and Taiwan (Housing)
  • 3 Year Warranty

Cycle Lumenator Specifications

  • 1000 Lumens from 4x Cree XP-G R4's driven at 750mA
  • 15-100V AC or DC Input Voltage
  • 10 Watts Input Power
  • 5.5x2.1mm DC Power Jack with cable included
  • 41mm diameter x 78mm length (1.6" dia. x 3" length)

Mounting Bracket

The Cycle Lumenator comes with a handlebar clamp and mounting bracket for easy attachment to any bike with lateral and up/down directional alignment. No tools are required for installation, although the clamp and included rubber shim can be a bit loose on 7/8" tubing, so if possible mount the bracket near the stem where the handlebar tube is thicker or add some extra shimming material if you have thin bars.

Dual Lumenator

The included mounting bracket can also be used to install two Lumenator lights side by side in order to achieve 2000 lumens, in case 1000 isn't quite enough. We offer the 'Dual Lumenator' with a Y splitter cable that allows both lights to be run from a single tap into the power bus.

Power from Cycle Analyst

The included 5.5x2.1mm DC Power cable can be wired directly from the Cycle Analyst by opening the CA and soldering the red and black wires to the CA's V+ and Ground pads. Since the CA and Lumenator are usually both located on the front handlebars, this saves running the cable down to the battery pack. If you don't have a Cycle Analyst, you can make an Anderson Powerpole tap for use with Powerpole systems, or wire in to whatever connectors or terminals you have available on your battery.

Input Power


The light housing gets pretty hot, is this normal?
It is normal that the Cycle Lumenator housing will get pretty warm when the light is on. Even though these Cree LEDs are remarkably efficient, there is still several watts of heat to dissipate through the housing of the light. In flowing air, the casing temperature will rise about 25°C above ambient, while if the light is left on when the bike is still the casing can get 50°C warmer than ambient. That will feel hot to the touch, but all of the components inside are rated to take these temperatures and more so there is no worry. For best practice, turn the light off when the bike is sitting still, especially indoors.

Can I run it from the hub without a battery or with a dead battery?
Yes, if you have a direct drive hub motor (Nine Continent, Crystalyte, Wilderness Energy etc). The Cycle Lumenator can even be powered by a standard unregulated bicycle generator/dyno-hub. Due to the significant power requirements, the light will flicker while the bike is getting up to speed, especially with a regular 3W dyno-hub. Let us know if you are interested in using our lights with bicycle dyno-hubs.

Can I run the Cycle Lumenator from a 12V source?
12V is enough to power up the light, but the full power of the Cycle Lumenator is unleashed only at source voltages of 15-100V.

Is there any way to dim the brightness level or change to a flash mode?
At the moment, the brightness level of the Lumenator is not adjustable and lights this bright should not be allowed to flash. The Cycle Lumenator is a light designed to illuminate a huge section of the road in front. If you only need lights to make yourself visible to others, consider our Waterproof LED Lights which are not quite as overbearing.

Waterproof LED Lights (15-100V input range)

Two Front 12 LED and one Rear LED light. Photo by Mick.

Our series of ruggedized LED ebike lights stemmed in part from frustration with all the inexpensive flashing bike lights out there. You know, the $10 plastic lights with two AAA batteries that shatter all over the ground when you crash, that corrode at the battery contacts when you take them in the rain, that unclip and fall from their mounting bracket, or that simply get lost? In 2007, after growing tired of going through 2-3 cheap LED bike lights every riding season, we set out to make a single light you can strap on your ebike that will last forever and you'll never have to worry about charging separate batteries.

The result of our development is a 100% epoxy encapsulated lighting system that can be run for days under water, driven over with a car, smashed with a hammer, and will still keep running. Our unique manufacturing techniques allow us to include a waterproof on/off/flash button and have the LEDs exposed but recessed to prevent damage. Did we mention that they run off your ebike battery? We currently have two models in production:

Additional Details


The LED lights are designed with a pair of holes going through the housing so that they can be readily secured to the bike tubing with a pair of zip ties. The front light has a machined groove on the bottom and sits on top of the handlebar. The rear light is secured with zip ties in a similar manner either to the seat post or rear rack.

Wiring the Power

These bike lights need to tap into your electric bicycle battery pack for power. They are supplied by default with bare stranded wires (no connector) but can be upgraded with an Anderson Power Pole Tap (pictured) at the time of purchase, or by choosing the LED Light Kit. Since most ebike systems don't have a convenient access point for running auxiliary devices from the main battery, a small amount of custom wiring is required for some systems. We suggest any one of the following techniques:

Anderson Powerpole Tap

  1. Anderson Powerpole Tap: Available as an upgrade at the time of purchase from, or automatically included with the LED Light Kit. The Anderson Tap will allow you to plug the lights in directly between any battery and motor controller equipped with Anderson Powerpoles.
  2. Cycle Analyst Tap: If your system already has a Cycle Analyst, then there is already the full battery power available at the handlebars and you can tap into this rather than running an additional wire down the bike. This approach will require opening the Cycle Analyst box and soldering the wire to the battery power leads which you'll find connected to the pads labelled V+ (red wire) and G (black wire).
  3. Battery Charge Port: One possible location to access power from the battery pack without additional wiring is through the charging port for the battery. If you attach a 3-pin male XLR connector to the leads of the bike light, then this can plug into the charge connector on the battery pack for powering the lights up while you are riding.

There are certainly other possible ways of accessing the battery voltage, such as a tap inside the motor controller, wiring an additional auxiliary power line directly to the terminals of the battery pack, or partially stripping the insulation off the battery leads and splicing in this way. Just note that by default, the lights are supplied with bare wires on the end, and you'll need to do a bit of work to hook it up.

Remote Flash Control

While the front and rear LED lights do have a built in on/flash/off control button, it is also possible to either flash a 'steady on' light or 'steady on' a flashing light remotely by hooking up the white wire to an external switch. A third white wire can be found by stripping back the insulation of the light cable. Shorting the white wire to ground (black wire) results in an 'on' light flashing or a flashing light becoming steadily on. To return the light to normal operation, simply disconnect the white wire (open circuit). DO NOT ever connect the white wire to the red wire (V+) as this can lead to a non functioning light. This extra remote control can be useful for those wanting to use two rear lights to signal turning left or right, or those with an ebrake lever who want to draw extra attention when slowing down. Note that when the light is in the off mode, nothing will change by shorting the white wire to ground.

Power from the Wheel

If you have a direct drive hub motor (Nine Continent, Crystalyte, Wilderness Energy etc.) the hub motor itself can act as a generator and power the lights up so that you aren't riding in the dark, even if your main battery pack is toast or not connected. So long as the motor controller remains connected to the hub, it will rectify the AC voltage produced by the spinning wheel and convert this to a DC voltage which will supply power to the light. Most hub motors will produce enough voltage at about 6-8 mph to cause the lights to turn on.

DC-DC Converters (Stand Alone, 15-75V input range)

For those who already have their own lighting system, or maybe who want to bring along a portable radio, i-this, or e-that, we manufacture stand alone DC-DC converters with 5,6 and 12V outputs. Our DC-DCs are rugged and compact, completely potted in thermal epoxy leaving no concern of water, dust or snow damage, or of exposed metal pins shorting out against the bike frame. They have a sturdy 18 AWG power cable at the input through to a straight 5.5x2.1mm DC plug on the output, along with the mating DC plug jack for you to wire in to your own system.

If you've got another connector you'd rather use, or want to wire it up permanently, chop off the connector and go for it, just be sure to check the polarity before hooking it up to your valuable devices. Also note that all of the DC-DCs we currently offer are NOT isolated, meaning that the output ground is always the same as the rest of your system and that they cannot be doubled up to run in series.

  • 5V(10W) is ideal for charging your USB devices (Warning: custom wiring required and no current limiting so be very careful to make sure you know what you are doing. We are not responsible for turning i-whosits into coasters).
  • 6V(10W) is perfect for older halogen systems based on the dynamo standard.
  • 12V(20W) works with the halogen lights we offer and many other systems (lights, radios, automotive) just keep in mind the output power limit.

All devices come in the same slim 42x23x12mm (1.7x0.91x0.47") package with about 60cm (24") of 18 AWG cable on the input side, 90cm (36") at the output plus another 30cm (12") attached to the included mating plug. They can be upgraded with an Anderson Powerpole Tap at the time of purchase or with bare stranded 18AWG wires.

When drawing close to the maximum load, the DC-DC converters will get quite hot so it is best to keep them exposed to air flow under high load situations rather than tucked into a padded bag. They have an internal temperature shutdown to protect the internal circuit but by that point the block of cheese sitting next to them stuffed inside your pannier could be a little melted.

We also accept custom orders for other output voltages in the 5-20V range (maximum power output of 2 amps x Vout). If you already have a high power LED system, halogen or HID light with a limited input voltage range and are tired of worrying about a separate battery pack, let us know. A small fee applies to small quantity custom orders and a couple of weeks lead time should be expected.

Last Updated: December 15th, 2010

Photo credit: Mick

The information in this article was current at 06 Dec 2011

Keywords: Battery