60 LED neopixels power/voltage question

[Elemental108]

Hi guys, I purchased two metres of the 60LED neopixels, so I have 120 LEDs arrayed in a 20x6 matrix. Can I use 4AA batteries (6V) to power these or is that too much? Would 3 (4.5V) be just fine?

Also, if my Arduino UNO is separately powered by a 9V battery, do I need a logic level converter? Or will this just work without one?

Regards,

Adam

[Franklin97355]

I would go with 3 batteries if they are alkaline (4.5v) or 4 if NiCad or NiMH (4.8v) The 9v battery will be regulated to 5v for the Arduino so you don't need a comverter but none of these batteries will last very long in this scenario.

[Elemental108]

Thanks for the prompt reply.

How long will this set up last roughly? If it is around 5-10 hours then I am happy with this.

Otherwise what would you suggest for a more power efficient and longer lasting portable set up?

I'm basically building a portable hand held LED sign.

[michaelmeissner]

Like most things with neopixels, it depends on how many pixels are lit, and the power level the pixels are displayed at. The worst case is when every single LED is on and running at full power. This will draw 7.2 amps which is more than many batteries can supply. This means you might need to use several batteries in parallel to deliver that amount of power.

If you convert the power from a higher or lower voltage, you will have some loss in the conversion (and the conversion loss is usually through heat, so you may have to plan to vent the heat).

If you light up fewer pixels, and limit the maximum power of the pixels, you can bring the total amperage down to 1-2 amps (at 5v), which can be done with a single battery (or group of AA batteries)