Lambda SMJLED with 6Volt ?

Zionxem · Sep 14, 2006

Hello

I received some SMJLED from the sandwich shop,they can't answer me if the SMJLED will work with 6 Volt (2 cells) in a microlight photon freedom.
Please someone have the answer ?
Does i have to use just one CR2032 cell ?

thanks

Varroa · Sep 14, 2006

There are many threads about this already but the short answer is no. Anything over 3 volts will kill the light (even 3.6 volts from a lithium will degrade the light output in a short amount of time). The SMJLED S.S. from the sandwich shop is best suited for 2 x nimh batteries (2.4-2.8 volts) but will run on 3volts. Hope this answers your question.

Zionxem · Sep 14, 2006

Merci Varroa....

chimo · Sep 14, 2006

One thing to consider with the button cell lights is that the batteries have a fairly high internal resistance.

What happens is that voltage is dropped internally in the battery as the current increases (the higher the current - the higher the voltage drop). This means that the load (the LED) does not actually see 6V when two series batteries are used. In reality, the LED is initially overdriven for a very short period and then "settles in" at a "safe" level. These batteries do not have a great storage capacity and cannot maintain overdrive currents for very long.

One quirk about the SMJLEDs is that they have a much lower forward voltage than other 5mm LEDs. The initial drive current *may* be too much for them and melt a bond wire.

Varroa · Sep 14, 2006

chimo said:
One thing to consider with the button cell lights is that the batteries have a fairly high internal resistance.

What happens is that voltage is dropped internally in the battery as the current increases (the higher the current - the higher the voltage drop). This means that the load (the LED) does not actually see 6V when two series batteries are used. In reality, the LED is initially overdriven for a very short period and then "settles in" at a "safe" level. These batteries do not have a great storage capacity and cannot maintain overdrive currents for very long.

One quirk about the SMJLEDs is that they have a much lower forward voltage than other 5mm LEDs. The initial drive current *may* be too much for them and melt a bond wire.

I agree but there has been no tests done on button cells using this bulb and all of the test that have been done say don't use anything over 3 volts. In reality the button cells probably can't provide enough current to drive this LED very well so it may be very dim.

Paul6ppca · Sep 14, 2006

I got some smjled from triton here on cpf,I have used 2 of them in keychain lights.One runs 3 lr44 1.5 volt and a keymate that runs 4 lr44 1.5 v.Both have help up perfectly for months. Using the keymate ,the smjled is much brighter than stock.

abvidledUK · Sep 14, 2006

I've been running an SMJLED at 3.6v for some months now, no degradation yet.

It's a direct soldered in replacement for a dead "Luxeon" in a MXDL 3AAA 1w torch.

https://www.candlepowerforums.com/threads/120259

Varroa · Sep 14, 2006

The SMJLED is a totally different beast then the SMJLED S.S., they don't use the same die or anything. See: https://www.candlepowerforums.com/threads/128801

vortechs · Sep 14, 2006

Zionxem said:
Hello

I received some SMJLED from the sandwich shop,they can't answer me if the SMJLED will work with 6 Volt (2 cells) in a microlight photon freedom.
Please someone have the answer ?
Does i have to use just one CR2032 cell ?

thanks

Hello Zionxem,

I put a 'uncut' (full acrylic dome) SMJLED into a LRI Photon Freedom microlight. It seemed to run just fine on 2 x 2016 coin cells. The internal resistance of the tiny coin cells helps protect the LED so that the LED doesn't actually see 6V. It is initially very bright when the coin cells are still fresh but the brightness depends a lot on how depleted the coin cells are.

Here is the thread where I installed the SMJLED in the Photon Freedom: https://www.candlepowerforums.com/threads/114298

I am now running the SMJLED Freedom on a single 3.6V Li-Ion LIR2032 coin cell. It is a bit brighter than it was on the two 2016 coin cells because the LIR2032 does not have as much voltage drop under load.

Zionxem · Sep 17, 2006

Hi Vortechs

Thanks for your advice.
i'ved try it with 2X2016 and it's less bright than a nichia CS....
Please do you have some link for the 3.6V Li-Ion LIR2032 coin cell ?
Thanks and excuse me for my poor english.

Peace,
Max.

abvidledUK · Sep 17, 2006

Zionxem said:
Please do you have some link for the 3.6V Li-Ion LIR2032 coin cell ?

http://www.duracell.com/oem/productdata/default.asp

http://data.energizer.com/DataSheets.aspx

vortechs · Sep 17, 2006

Zionxem said:
Please do you have some link for the 3.6V Li-Ion LIR2032 coin cell ?

Try this thread:
https://www.candlepowerforums.com/threads/93125

Lambda SMJLED with 6Volt ?

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