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There are many various lights currently on the market that are marketed as "designed for E-bikes". They have external power connectors. Of course, the voltage must also match but I am not even there.

My E-bike seems even having some support for lights, as there is the "lights" button on the control panel (seems not doing anything). The engine is Bafang 36V/250W Maxdrive if matters but probably generic advice where to look for may be even more valuable.

I have looked visually around the motor, the control panel, there is no any obvious socket available. Where should I look for the terminals to connect the externally powered light?

I use the bicycle daily for commuting and need lights quite often in the evening. Monitoring over the charging level of the front, rear light, also the main battery requires attention. It would be simpler to watch over the single battery only.

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    I have no idea but maybe there are several models of your battery/controller which share the same control panel. So the lights button doesn’t necessarily indicate the existence of a port somewhere. In Austria and Germany lights had to be dynamo-powered until recently, so it didn’t make sense to add an output to the battery/controller.
    – Michael
    Jul 15 '21 at 10:25
  • Details of the control system, especially the panel, are far more important than the type of motor. I have worked on e-bike lighting, for a model which powered a front light via the control panel but had an independent rear light. I had to open the control panel and splice wires. You may well have to do the same (with associated warranty risks)
    – Chris H
    Jul 15 '21 at 10:34
  • My bike has a USB port for providing power, mounted on the handlebars. Presumably the presence and position of such a port will vary from bike to bike.
    – Chenmunka
    Jul 15 '21 at 10:39
  • BTW some of the cheap lights are pretty poor. The rear light I fitted ("24-36V") turned out to be several white LEDs connected in series with an inadequate resistor even for 24V and a red filter, also inadequate so combined with the overcurrent the light looked pink.
    – Chris H
    Jul 15 '21 at 10:39
  • @Chenmunka is that switched and intended for lighting? There are 5V-input lights, especially front ones, but the ones intended for e-bikes normally run at the main battery voltage
    – Chris H
    Jul 15 '21 at 10:40
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My understanding is that the EU has a bunch of rules about bike lights that don't apply anywhere else in the world.

So in Europe your bike is much more likely to have a hard-wired light and perhaps a dynamo to power it. With the advent of ebikes, a hard-wired battery powered light becomes more convenient.

Your Bafang motor is not an ebike - the controller is probably a generic part as is the dashboard panel. That it has a Lights button doesn't mean there's anything to connect it to and control.

Instead, check the details of your specific brand of bike, and if theres nothing useful, look for generic details on your controller and console boards. It is possible there's a +12V DC switched terminal, or it might be a 6V AC terminal intended to use existing dynamo lights. Or some third option is also conceivable... a 3V circuit with the frame as ground might also be a valid option because its 2x carbon battery cells, like the bike lights of old.

If you're not up for manipulating wires, then perhaps stick with some battery lights for your bike. At least they won't run down your main motive battery.


European law varies from state to state.

Example:

Germany – Dynamos are required by law, they must be attached, the battery light alone is not permitted (except for race bikes)...

Austria – Battery lights are allowed and they can be detachable...

Switzerland - Battery lights are allowed and they can be detachable, must be seen from 100m, ...

Netherlands – Battery lights are allowed, detachable or fixed to the body, ...

France – Battery lights are allowed, detached only, ...

page 16 of https://www.anec.eu/images/Publications/technical-studies/ANEC-RT-2012-TRAF-002.pdf

Upshot, in Germany your ebike is not legal for lighting unless it has a dynamo as well. Nominally, your ebike with a hardwired light is still battery powered. Whether this is enforced, is another question.

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    Th EU rules weren't fully harmonised by the time the UK left. 6VAC would make sense but I've never seen that as an output and given the range of voltage and frequency you can get from a dynamo, all modern lights rectify to DC while incandescents don't care, thus 6VDC would be reasonable. But as far as I can tell, even Germany doesn't require permanently fixed lights, it's just that dynamo lights are very common and are permanently fixed
    – Chris H
    Jul 15 '21 at 12:15
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    Because e-bike are fairly harmonised, they do have to be pedelecs everywhere in the EU, and that means they have to function as a normal bike if the battery is flat, and you need lights after dark. Relying on the motor's battery for lighting may not be wise, but a backup set could be very small
    – Chris H
    Jul 15 '21 at 12:17
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    I think that requirement for dynamo likely have been dropped as most the bicycles I see around use battery powered lights. It made more sense in the past when the battery was much more likely not to be good when needed.
    – nightrider
    Jul 15 '21 at 19:53
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    §67 StVZO is the most relevant, I guess. Jul 18 '21 at 19:39
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    I do carry small emergency only front and rear lights that are ready in case the main set get discharged. But I want the main set to be much brighter.
    – nightrider
    Jul 19 '21 at 7:25

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