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How long can a 9v battery power a few leds? Answered

Hi I am trying to make a display of my polymer clay angry birds in our local fair and I wanted to add a few little leds on it, the problem is they need to stay on constantly for at least 5 days  I am trying to figure out how long a 9v battery would power about 6-8 leds. is there a better way to do it?




3 years ago

If the battery is an Alkaline battery then it is about 625mAh if your LEDs draw 10mA each then your looking at 60 mA for 6 Leds so 625/60= nominally 10 hours - It will be less and as the battery discharges the LEDS will get dimmer.

You WILL need a suitable resistor in series with each LED.