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I was hoping to power a 1 watt LED (would be great if this is capable of powering 2 or 3 watt LEDs) with a 3 volt coin cell.

  1. Will the coin cell be able to output voltages and amperages that are within acceptable levels for the LED's operation? Essentially, will the LED or battery fail faster than is considered normal?

  2. If I need to add resistors to the circuit, what kind of heat levels will they produce?

The battery would ideally be a CR2032 lithium cell, chosen due to a size requirement.

The LED has a forward voltage of 3.2-3.4 volts and a max. forward current of 350 mA.

MicroservicesOnDDD
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Thomas Wood
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    I'll suggest just grab a pair and try it. – Passerby Apr 08 '21 at 15:09
  • To give you an idea of how far out your are in size, an 18650 Lithium Ion rechargeable, which has excellent energy density, is a good match for 1W-5W LEDs. 5W willl run a flashlight fairly hot for an hour and a half to two hours on a single 18650. Worth noting brightness and total power decrease as the flashlight heats up, which may or may not be comparable or better/worse than your case if you have size constraints. – K H Apr 09 '21 at 03:48
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    Don't let them fool you. This is exactly the way many keychain lights work. Like @Passerby said, try it out! – MicroservicesOnDDD Jun 12 '23 at 20:16
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    @MicroservicesOnDDD Keychain lights don't run a 1W LED. – SiHa Jun 12 '23 at 20:33
  • @SiHa -- What you mean to say is "at full power". Google Phillips Dubai LED Lamps which power LED filaments at quarter power (4 times the LED's for same brightness) and achieve a 200 Lumen per Watt efficiency (I believe). Underpowering an LED is a great way to acieve the best efficiencies. So, I would put a 1 watt LED in a keychain light in a second! And it would work really well, too! – MicroservicesOnDDD Jun 12 '23 at 23:31
  • @SiHa -- OP does not actually specify full power, though that has been the consistent assumption for many who have answered. OP asks "Will the coin cell be able to output voltages and amperages that are within acceptable levels for the LED's operation?" and a CR2032 will do that, quite nicely, especially with a Joule Thief, as user "fifi_22" has answered. – MicroservicesOnDDD Jun 12 '23 at 23:43

4 Answers4

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The answer to this question is just to look in the datasheet. You'll see that this cell is hopelessly wrong for what you want to do.

The Panasonic CR2032 states 225 mAh capacity and typical max. load current of 200 uA.

So it can't remotely supply the load current. Even if it could, it would be flat in 40 mins.

You must search for parts (battery) by their characteristics (capacity, max current) and then choose the right part. You can't start with the part and try and make it fit your application.

TonyM
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This won't work. You're asking a source of power (battery) that's designed to maybe supply 60 mW to supply 1 W.

End of story – you need a different power source, no circuit is able to create power (physics wouldn't allow that).

Marcus Müller
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    There's no conservation of power law, only conservation of energy. It's definitely possible to run a multi-watt LED from a coin cell - just not at 100% duty cycle. – pericynthion Apr 09 '21 at 18:39
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If you want a tiny battery with a flat shape that can deliver that kind of power (but not for long) you'll have to use a pouch LiPo.

bobflux
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It will not light it up to maximum level (very low current due to high internal resistance of the battery), but using a Joule Thief circuit one may get some light out of this diode. It is simple circuit with 5 components, but needs a custom transformer.

fifi_22
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  • Yes, and it will work to a lower voltage, so the battery should last longer (if drawing a reasonable amount of power). Suggest setting the resistor higher, like 2k2 or 4k7, whatever is sufficient. I find 5mA at the LED sufficient for many tasks -- it depends on the ambient light level. Best solution is changeable brightness (and focusable LED). – MicroservicesOnDDD Jun 12 '23 at 20:11