LED Lights - Battery Drainage

[OneWheel]

Hello,

Wondering how much battery is wasted with the LED lights turn on for a full charge 30km ride.

Thanks.

[SuperSport]

That's an interesting question.  They don't really show much during the day, so how much distance, if any, could be gained?  Sounds like a good test to try.

[esaj]

If you can measure the voltage and current going into the led-strips, you should be able to calculate the amount of power they use, current (amperes) * voltage (volts) = power (watts). Depending whether they're just lit up all the time or displaying different patterns also affects. You could measure for longer while the pattern is playing, then calculate the average power it uses.

Thinking how much battery is wasted with the lights over a certain range isn't that useful, as it depends on your speed (ie. how long they are being lit, if you ride 30km at an average speed of 15km/h, it's going to be 2 hours, if you could ride at an average speed of 30km/h, it would only be one hour). Instead you should look at the time they're being lit. For example, the Firewheel has a single large led-light in front (3W or 5W maybe), and one in back (that becomes brighter when you brake) that might be less powerful. Assuming the "worst case" that they both were 5W and burning fully bright all the time, the total power would be 10W. If the lights are then kept on at full brightness for an hour (regardless of the speed or range or even if the unit is moving), they use 10Wh (watthours) from the battery over that hour. Likely the led-lights on Ninebot are much smaller than 3W or even 1W per piece, so it's probably not using that much battery (comparing that the motor can take hundreds of watts or over a thousand in climb/fast acceleration).

[dpong]

FWIW, I agree.  I doubt one would be able to tell any discernible difference at all.  

[esaj]

Actually, @Cranium had measured the leds and calculated the power:  http://forum.electricunicycle.org/topic/2234-idle-power-measurements/

 

<QUOTE>

Next test was to measure the maximum current used by the LEDs while sitting idle.  To determine the max, I set the light mode to Breathing with the color being white.  This was hard to measure using the Rigol Power Supply due to the slow refresh rate of the LCD screen.  So for this test I swapped down to my Mastech power supply with the Fluke in series being used for more accurate current measurement than the Mastech can supply.  The results fluctuated up to about 185mA at its peak and with the LEDs turned off, it was 75mA.  There are 9 LEDs in each strip, 2 strips in each ring and 2 rings for a total of 36 LEDs.  At max power this many LEDs are rated to draw 11.4 Watts.  The Ninebot is using at most 100mA or 6.6 Watts of power so they are being very conservative and these LEDs could actually be brighter than they are!

</QUOTE>

So at 6.6W max, you could save 6.6Wh at most per hour if the leds weren't turned on. Not that much, considering you are using (depending on your weight, hills etc) something like 10-20+Wh per kilometer.

[Flavour]

So you can get about 0,5 km extra, which can save your ass when you drain the battery by riding too far

[Cloud]

Whatever you are calculating guys, i would not believe for a second that having the led light on will make any impact on the distance that one can discern. I can feed an led light from a little tablet battery. If the same energy could propel one for half a kilometer, then the unicycle batteries taking me over 20 miles would fit into my wallet. 

Even when i play the music super loud for 2 hours i dont notice any difference in the mileage, even thought i believe that not having it on could move me an extra several hundred feet

[Flavour]

Well, the batteries in our Ninebots aren't that big, I think they're actually wasting place and there is a lot of free space in NB to fill with even more batteries (on the other side with motherboard and inside the metal ring).

You can simply calculate everything with normal external batteries used to power external lights (front and back). I wanted to power my light with the internal battery, but that's too risky, even for LEDs.