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

### Re: Good quality head- and tail-lights for electric bicycles ...

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

### Re: Good quality head- and tail-lights for electric bicycles ...

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

### Re: Good quality head- and tail-lights for electric bicycles ...

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://www.7gen.com/

### Re: Good quality head- and tail-lights for electric bicycles ...

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://www.7gen.com/

### Re: Good quality head- and tail-lights for electric bicycles ...

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

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