burning three 3.5 volt 20 ma LEDs in series with a 100 ohm resister. I have it hooked up to two 6 volt lantern batteries in series (Raovack). They are suppossed to be the good ones that last 4x longer. If I left in on continuously, how long would my batteries last?
How long will my batteries last?
- Thread starter jfones
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kuksul08
Enlightened
We need to know the capacity of the batteries, usually in mAh
Mr Happy
Flashlight Enthusiast
Voltage across resistor is 2x6 - 3x3.5 = 1.5 V.
Current through resistor is 1.5 V / 100 ohms = 0.015 A = 15 mA.
Battery capacity is 20,000 mAh.
Estimated battery life is 20,000 mAh / 15 mA = 1300 hours.
If you leave it on continuously it is going to run for about 8 weeks with gradually falling light output.
Current through resistor is 1.5 V / 100 ohms = 0.015 A = 15 mA.
Battery capacity is 20,000 mAh.
Estimated battery life is 20,000 mAh / 15 mA = 1300 hours.
If you leave it on continuously it is going to run for about 8 weeks with gradually falling light output.
