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how many red led can i hook up directly to 3v 2032 battery, in parallel. do i have to use a resistor? Answered



As in LED throwies - a 2032 + LED - No resistor. They rely on the internal resistance of the battery to limit the current.

How may? Well you might just have to try and report back. Nothing nasty should happen if you over load the battery.

Of course the more LEDs you put on the shorter time the battery will last.

The nominal capacity of the battery is 240 mA/h so in principle drawing 10 mA for each LED should give you 24 for 1 hour or 48 for 30 mins or 96 for 15 mins

To be honest reality will be somewhat short of this ideal.

I think a red led requires less than 2v (1.8?) So 3v is probably too much, and if you connect 2 in series 3v won't be enough. I think if you connect a resistor that will drop a volt in series with each led, then you can put as many as you like in parallel, as long as the battery can supply the current to light them up. Keep adding resistor plus led until it doesn't light up any more. I also think I'm about to be shot down by everyone with even a basic grasp on electronics, but there you go. If that's the worst thing that happens to me today, then coooool.