I've been riding my bike many nights wondering the following question:

What consumes my LED bike-light battery: the continuously on setup or the blinking setup?

It might seem trivial, since the longer the light is off (so during blinking), the longer the battery will last.

However, I am not sure because timers (to create the blinking) or relays also consume power...

So, which is the best setup for the most long-lasting LED bike-light?

Thanks for your help!

  • $\begingroup$ You might consider setting a given distance limit, as the human eye sees a rapid blinking light more than it will a continuous light. On that basis, on average, you will probably use less power for an assumed level of visibility. But this question has biology and electrical engineering aspects to it for a full answer here, imo. $\endgroup$ – user178231 Dec 13 '17 at 0:09
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    $\begingroup$ I think this might be on topic here, but would fit and be answered better on the Electrical Engineering SE. $\endgroup$ – knzhou Dec 13 '17 at 0:21
  • $\begingroup$ So... a matter of syntax: The way your question is written, the answer is 'Both'. Each of the settings use energy, so they both consume your battery. $\endgroup$ – Jakob Lovern Dec 13 '17 at 0:33

If your light uses a filament lamp then almost certainly a continuously-on setup would consume the most power. But presumably your light uses LEDs, which are much more energy efficient.

Your blinker circuit is almost certainly not relay-driven; if it were then the relay activation would consume a lot of power, possibly more than a filament lamp. It could be a timing circuit with a resistor-capacitor combination and transistors but more likely a timing circuit (e.g. 555 timer) which, without looking up specifications, I suspect to be more energy efficient than a RC combination.

I think that with an electronic timing circuit and LED light, a continuously-on mode would consume the most power, and even at a 50/50 duty cycle the light would still consume more power than the timer, but less than a continuously-on mode. For the timing circuit to consume more power than the light it would possibly need the light to be on less than half the time, which probably means it's still useful for being seen but not useful for seeing.

  • $\begingroup$ Thank you, that's actually what I thought. So, is there a way to calculate how much power the 555 timer consumes? Thanks $\endgroup$ – Jordi Ferrer Dec 14 '17 at 12:40
  • $\begingroup$ The 555 is obsolete. A bike light is likely to use a custom IC mass produced for the specific purpose. $\endgroup$ – RedGrittyBrick Jan 27 '18 at 13:03

Fast blinking light. More if you are using a element bulb. Less with an led because of the efficiently. The gap between the blink are 50% on and 50% off so half the power ruffly.


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