Good quality head- and tail-lights for electric bicycles or scooters, improving safety and visibility, at low energy cost

Webmaster's picture

An electric bicycle or scooter has a big battery, so it might as well have bright lights. Bright lights help you see the road, and they help you to be seen by car drivers, considerably improving your safety. Even during the daytime bicyclists are practically invisible and need to use every trick available to be seen, to give the highest chance to avoid a car accident. At night it's even worse, because the bicyclist can easily blend into the shadows and not be seen until its too late. We want you out there safely riding your electric bicycle or electric scooter, not to be an accident statistic.

Because electric bicycle and scooter design varies so much the advice here has to be general. We'll also try to cover lights for electric motorcycles.

Let's start with -- do you need high quality lights? We already went over the case, but it's worth reiterating:

  • Bright headlights mean you can see the road ahead and can avoid obstacles in your own right
  • Bright lights, and/or bright reflectors, means car drivers or pedestrians or other bicyclists see you, and can avoid colliding with you

The dinky blinky lights normally sold for non-powered bicycles are (in my humble opinion) inadequate. They barely illuminate anything, and are difficult to see. The problem is those units are tiny in order to stretch battery life for as long as possible because they're built around the assumption the bicycle won't be carrying anything more than a couple AA batteries. With an electric bicycle/scooter/etc we have a huge battery pack, by comparison, and can afford the electricity for a very bright lighting system.

A closely related question is, do you need to retrofit lights onto your vehicle? Maybe you own, or can buy, a manufactured electric bicycle/scooter/etc that already has bright lights built in. If so, your job may be done and you don't have to read further. Make sure that the lights are powered from the main battery pack.

Not that many years ago those of us who wanted an electric bicycle or scooter had to build our own. Today there is a growing list of manufactured electric bicycles and scooters, many of which have excellent parts and build quality. The price may be higher than a do-it-yourself kit, but how do you value your time -- it costs you time to build the bike versus buying it prebuilt -- how do you value the manufacturer warranty, or the fit-and-finish of a properly designed system versus a do-it-yourself hodgepodge? I've done the latter several times, and look longingly at the build quality of the OEM bikes.

For the rest of this let's assume you either built your own electric bicycle/scooter/etc, and need lights, or for some other reason want to retrofit better lights onto a vehicle.

Minimizing electricity consumption is useful to preserve as much riding range as possible.

  • Hyper-reflective materials are becoming commonplace and automatically shine back a bright light when struck by car headlights or other light. Some product lines are: reflective safety vests, reflective arm bands, reflective tape for bicycles and all kinds of other reflective gear can make you more visible without using any electricity at all
  • LED lights are extremely efficient, and newer models are starting to be bright enough to use for headlights. The efficiency is measured in lumens per watt-hour of electricity consumption, and LED lights are the new king of efficient lighting.

Electric Bicycle Lights.png

Here's a simplified diagram of an electric bicycle control circuit. What you're looking for is the connection between the battery pack and the controller, hopefully between the ON/OFF switch and the controller. The controller may have a connector to output power for head/tail/lights, and that should be used if it's present.

The basic idea is to attach a bright, white, LED light to the front of the vehicle, for the headlight, and a bright red light to the rear, for the tail light. The two are wired to a common circuit -- the positive and negative of each are wired together, and then positive/negative are wired to the power circuit. This way the lights turn on any time the vehicle is turned on. You may want to use a switch to control the lighting circuit so it's only used at night.

Recommended lights

Unfortunately most bicycle light units are designed with a stand-alone power source -- they're essentially glorified flashlights, powered off their own batteries. For our purposes we want the lights to be powered from the main vehicle battery pack. Because the majority of "bicycle lights" are not powered that way, we have to search carefully for the correct sort of unit.

Following are a selected list of headlights and tail lights that look good. Many of them have their own battery pack, which you'd have to charge separately, and they also tend to come with headbands allowing the light to be used away from the bicycle.

See also: headlights [amazon.com], all lights [amazon.com], tail lights [amazon.com], electric bicycle LED headlight [ebay.com], electric bicycle LED taillight [ebay.com]

Doinshop New Useful Motorcycle Accessory Electric Bike Waterproof 3W LED Headlight White: Depending on how bright this is, it's an almost perfect headlight. It works at any voltage from 12-80 volts, and has a simple two-wire connection for power. The trickiest part of using this unit is mounting the light to a bicycle. Notice it has a simple flat metal foot, with a single hole. Mounting this to a handlebar, for example, means fabricating something which bolts to the handlebar, to which you bolt this light unit.
Bright Eyes Rechargeable POWERFUL 1200 LUMENS Bike Headlight : This one is good but imperfect. It's bright enough to be a very good headlight, however instead of being powered from the vehicle battery pack it has its own lithium-ion battery pack.
SecurityIng Waterproof 3600 Lumens 3X T6 LED Bicycle Light 4 Modes Super Bright Bike Headlight LED Lighting Headlamp with 8.4V Rechargeable Li-ion Battery Pack and Charger: Same can be said for this one.
900lm Lumen LED Cycling Bicycle Bike Waterproof T6 Headlight Headlamp Kit Set: Same can be said for this one
ELETA Waterproof 2000 Lumens XM-L X2 LED Bicycle Light 4 Modes Super Bright Lighting Lamp Bike Light with 8.4V Rechargeable Battery Pack & Charger for Outdoor Activities Like Camping, Cycling, Hiking: This is a very bright unit - 2000 lumens - with two LED bulbs. Mounts on a handlebar properly, has its own battery pack and charger.

Lighting unit recommendations

Retrofitting LED lights into electric motorcycle lights

before comments

Comments

Hi,

Thank you for your post. I feel I must address a few points.

Firstly, your comments regarding 'bright is good' are generally valid but it is important to note that generally bright also means relatively high power consumption - as you yourself, rather contradictorily - point out later in your post. So there is obviously some compromise to be reached of lighting power Vs minimising energy use. It is up to the buyer to decide but some basic maths on the subject might be helpful.

As an example, lets look at a typical e-bike battery of 36V, 10Ah capacity with a typical motor of 250W. In order for the user to see how much of their precious battery capacity is going to be lost to a bright headlight, the most important specification of the light is how much power it uses in watts (W). In our example, the motor uses a maximum of 250W. The one (and only) example light you mention with a power consumption figure is the 'Doinshop' one at 3W.

If you compare the maximum motor power with this light's power rating (3W) you can see that the light will use about 1% of the motor power at full throttle. Obviously at half throttle the light will consume 2% and so on. To put this (power x time) energy use into context, the energy in the battery pack is found by multiplying the pack volts by the Ah capacity, i.e. 36V x 10Ah = 360Wh. So, if used at full throttle, our bike would go for about 360Wh / 250W = 1.44 hours or 1h:26m.

Another point I would take issue with is your apparently dismissive attitude towards the flashing type of light. Studies (and basic experience) will tell you that the flashing light is much more effective at drawing the attention of the human eye than a steady light of the same output, especially when it is in one's peripheral vision. A flashing light doesn't help particularly in seeing where you are going, tho. So, as well as a good headlight for night use, I would advocate good flashing lights front and rear, on DAY & NIGHT, ideally with a power reduction switch or, even more ideally, with an automatic power reduction for day use. The flashing rate should be around 4 times a second or so for maximum effect.

I would encourage buyers of particularly bright headlights to consider having a 'dip' function to avoid annoying other road users otherwise you may find your light causing more accidents than it prevents.

Lastly, also though many good lights are designed to be self-contained (i.e. not be powered by the e-bike battery pack but by their own self-contained batteries) there is nothing to stop the enterprising and DIY-inclined person from adapting them to running off the main pack. CAREFUL consideration of the respective voltages must be made, though, or you run the risk of destroying your shinny new light and possibly damaging your bike, too. The additional cost and complexity may put some off this idea but cheap and effective DC-DC converters are readily available on eBay etc that would make this a fairly easy job. It also means that you can permanently fix your lights to your bike to make it much less easy for a thief to steal the lights.

Regards, Martin Winlow.

Regards, Martin Winlow
Isle of Colonsay, Scotland
evalbum.com/2092

Scotter's picture

Hello,
I keep receiving webmaster updates to this topic. It seems like some kind of ad for electric bicycle lights -- over and over again. Adding more and more references to the first posting.

Perhaps I'm in a bad mood today, but am I the only annoyed by this?

Ironically, I'm developing a revolutionary lighting system for bicycles, cars and head/hat lamps. I think the dip feature is a good idea.

But still, updating the original post is getting to be spam-like.

Thanks

Scooter

--Scotter and his scooter
2007 Vectrix VX-1 Maroon
2007 Vectrix VX-1 Silver
2008 Vectrix VX-1 Blue
2008 Vectrix VX-1 Silver
Other EV projects in the works

Webmaster's picture

Hi Scott, thank you for the reply and your message via email as well. If/when your product is finished it would be a great addition to this page, right?

There have been multiple companies started by members of this forum, who posted lots of product information on the site. (Current Motor is one) It's fine that they did so, just as it would be fine for you to post information about your product. VisForVoltage is an open forum through which all of us can communicate with each other about our ideas, hopes, dreams, etc.

My goal for this page and other similar pages I've posted is to implement a different sort of advertisement/monetization. Rather than banner ads in the sidebar that direct visitors somewhere else, an informational posting like this should do a better job retaining visitors who then might become members of the site. Contrast this site with the thousands of other forum sites whose sidebars are chockablock with banner ads --- which is a better experience for the community?

If you want to further discuss a site-wide issue like this, such as what I'm doing for monetizing this site, it'd be better to start a new posting in the General area of the forum.

- David Herron, http://longtailpipe.com/

Webmaster's picture

Hi Martin, Good points. I'll try and add something to understand power consumption. I think you'd agree that the hyper-reflective tape stuff is a great way to achieve the goal without spending any power.

I'm clearly in the camp that bright lights are better ... The blinky lights look so feeble in the dark.

- David Herron, http://longtailpipe.com/

900lm Lumen LED Cycling Bicycle Bike Waterproof T6 Headlight Headlamp Kit Set: Same can be said for this one

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