Multiple emitters?

OK. So I'm still extremely noobish. Don't flame me too bad when I ask my question please

If you've got a drop in that has multiple led emitters a triple or a quad for example, does that mean that it can take more voltage before burning up than a single?

I wish there were a clear reference for this kind of stuff.

Thanks.

Now I may be mistaken but I think that multiple emitters are wired in parallel. This means there's a lower overall resistance meaning more current is drawn. So if 1 emitter in direct drive draws 4 Amps then 2 will draw 8amps, 3 draws 12 Amps, 4 draws 16 amps etc etc (assuming they are of equal resistance) Each emitter will still only 'get' 4 amps so will be as bright in a group as it would on its own.

Also just to help you out. Think of electricity as water. Voltage is a pressurised water tank, Resistance is the tap ,current is the amount of water flowing out of the tap and the device to be powered is a water wheel.
When you open the tap water flows. As tank empties the pressure drops, the lower the pressure the less flow, the less flow the slower the wheel spins.

I hope that makes sense.

Dthoreson81 said:

If you've got a drop in that has multiple led emitters a triple or a quad for example, does that mean that it can take more voltage before burning up than a single?

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No.

The voltage of a drop-in is not determined by the number of emitters in the drop-in.

Most quads and triples are meant for a single-cell (i.e. nominal 3.7v, full at 4.2v), and if you use more than a single cell, you will burn them up.

There are probably also some multiple-emitter drop-ins that can take higher voltages--it's a big world out there, with lots of options.

But as a general rule, there is no reason to think that more emitters means higher voltage.

It all depends on the driver, not the type or number of emitters. Dropins have a rated voltage range and you must stay within that range.

Tachead said:

It all depends on the driver, not the type or number of emitters. Dropins have a rated voltage range and you must stay within that range.

Click to expand...

So, playing devil's advocate for a moment, what's the point of 3-4x18650 length tubes? I know the soda can lights with 4x18650 cells are set up differently. This is mostly my curiosity getting the best of me.

Dthoreson81 said:

So, playing devil's advocate for a moment, what's the point of 3-4x18650 length tubes? I know the soda can lights with 4x18650 cells are set up differently. This is mostly my curiosity getting the best of me.

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I am not sure what you are asking?. Again, its all about the voltage range that the dropin supports. A 3 x 18650 tube would be to support a dropin with a voltage range of up to about 13V because 3 x 18650's have a voltage of 12.6V(4.20V x 3) when fully charged.

Multiple emitter dropins are usually used to give a higher output(brightness) then a single emitter could do by itself.

Dthoreson81 said:

OK. So I'm still extremely noobish. Don't flame me too bad when I ask my question please

If you've got a drop in that has multiple led emitters a triple or a quad for example, does that mean that it can take more voltage before burning up than a single?

I wish there were a clear reference for this kind of stuff.

Thanks.

Click to expand...

Not to be "flaming" you but there usually IS a clear reference for this stuff, and most times it is found with the drop in you buy...either in packaging or on the specs page of the website where you buy it. Most reputable places will give you an operating voltage range that the module is safe to be used within. Deviate at your own risk.

I have not seen a 3-4x cell tube extension in use either in person or mentioned on these forums since joining. I am not talking about soda can lights but the single inline tubes. Usually the single inline tubes get extensions to increase runtimes a bit but because they necessarily increase the voltage as well because the cells are in series, the drop in must be capable of operating at the higher voltage.

OK. I guess to be more clear, what makes one led able to use a higher voltage than another?

Drivers can boost voltage up or buck it down.
Leds can be 3v, 6v, 12v, commonly. (Compare xml2 vs xhp35.)
Multi leds can be wired multiple ways.

Short answer, there is no short answer. Too many variables and no guaranteed consistency light to light.

Some LEDs are designed to use different voltages. Cree XP and XM series and Nichia 119 and 219 are designed for 3V give or take a few tenths. Then there are Cree XHP50 and XHP70 these are designed for 6V. Then there is the XHP35. This is designed for 12V.

if you put 3V emitters in parallel they stay 3V. If you put them in series you need to add the voltages of the LEDs. For example 3 XP-L in series gives you s forward voltage of 12

staticx57 said:

Some LEDs are designed to use different voltages. Cree XP and XM series and Nichia 119 and 219 are designed for 3V give or take a few tenths. Then there are Cree XHP50 and XHP70 these are designed for 6V. Then there is the XHP35. This is designed for 12V.

if you put 3V emitters in parallel they stay 3V. If you put them in series you need to add the voltages of the LEDs. For example 3 XP-L in series gives you s forward voltage of 12

Click to expand...

So it IS the same as batteries in SERIES, voltage output is increased- LEDs is series: increase in input capacity...?

In PARALLEL, batteries only increase runtime not output, and LEDs in parallel don't increase overall input capacity... ?

Dthoreson81 said:

So it IS the same as batteries in SERIES, voltage output is increased- LEDs is series: increase in input capacity...?

In PARALLEL, batteries only increase runtime not output, and LEDs in parallel don't increase overall input capacity... ?

Click to expand...

Yes, where "input capacity" means "needed voltage".

Dthoreson81 said:

So it IS the same as batteries in SERIES, voltage output is increased- LEDs is series: increase in input capacity...?

In PARALLEL, batteries only increase runtime not output, and LEDs in parallel don't increase overall input capacity... ?

Click to expand...

Not exactly...

In series the LEDs require more voltage, not more current to light them all at the same level. Three 3volt LEDs running at 300mA will need 9 volts at 300mA to light. The series circuit requires electrons flowing through with more force (voltage) to get them through the LEDs.

In parallel the LEDs require more current, not voltage to light them all at the same level. For the same LEDs as above, you'll need 3 volts at 900mA to light them at the same level. In the parallel circuit, you need more electrons (amps) to supply the LEDs and light them to the same level.

Also there is both a 6 volt AND a 12 volt version of the XHP70. Always refer to the specs of the LED you are using, not just generalized specs for a product line.

Tachead said:

It all depends on the driver, not the type or number of emitters. Dropins have a rated voltage range and you must stay within that range.

Click to expand...

Exactly. A good example of this is the Sportac triple. With the Sportac, you have the option of either a single mode or two mode. The single mode is optimized for two Li-Ion cell operation and the two mode for single cell operation. In fact, two cells will fry the two mode drop-in. The difference here is the driver.

Dthoreson81 said:

OK. So I'm still extremely noobish. Don't flame me too bad when I ask my question please

If you've got a drop in that has multiple led emitters a triple or a quad for example, does that mean that it can take more voltage before burning up than a single?

I wish there were a clear reference for this kind of stuff.

Thanks.

Click to expand...

Nope. Not more voltage.

Multi-emitter dropins are usually wired in parallel. Meaning they take the same voltage as a single-emitter light. However, with multi-emitters, a FET driver, and spring bypasses, the light should be able to pull many more amps of current than a single-cell light.