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Noobariffic LED art question (Batteries) Answered

Uhh, hi everyone.

I have a super basic question, and I'm going to appeal for help because I'm running low on time for this project.

I have a signpost I want to light up with about 100 3volt LEDs. What kind of power source should I be looking at? Would 4 AA batteries suffice?

I've seen online calculators for determining resistors, but not for an ideal power source. Do I just wire up as many batteries as I want and get the proper resistors? I'd like this thing to light for at least eight hours on a full charge, so I can swap batteries daily.

Thank you in advance! I'm dumb!


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7 years ago

What type of leds are you planning to use?

If you're using "standard" 5mm through-hole leds: I'd choose an external power supply that you plug into mains, if the circumstance permits that. The cheapest solution is a wall-adapter, I think. Look for one that can provide 9 Volts and _at least_ 1 Amp. Your leds will do fine with 9 Volts if you change the resistors accordingly.

(LEDs need 15 to 30 milliAmps current, depending on the color. 100 Leds will take 4,5 to 9 Watt power at 3 Volt. Such power will drain batteries pretty fast)


Reply 7 years ago

Ooooh, yeah, circumstances don't *really* permit... but it might be cheaper for me to buy one of those Car-boosting Power Packs with AC outlets than to buy a gazillion rechargable batterys. More useful, too. Hmph.

See, it's an art display for an outdoor festival.