Any idea of current (power/voltage) consumption by CREE driver?

ArminVanBuuren

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http://www.ebay.com/itm/IP-65-CREE-...802?pt=LH_DefaultDomain_0&hash=item1e68c9ba6a

I purchased this, but have no idea how much current at what voltage it draws. Are there any specifications concerning CREE XMT T6 LED's driver? I've read a range of 0.7 to 2.8 amps at 3.3v, which is quite wide.

Especially, I would like to compare it to this product, which is claimed to have a "booster circuit":

http://www.ebay.com/itm/110992304085?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649

How much does it boost? Can the power consumption actually reach SLOWER values, even though 3 LEDs are involved? Any ideas about P | I | U here?

Thanks a lot.
 

Conte

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I don't have any experience with these specific units, but I am a technician and know enough to interpret the specs I'm seeing in those listings.

Let's see if I can answer your question.

As you've read, the Cree XML consumes between 0.7 to ~3a of current.
The light you bought has multi output modes on it. Think of it as a dimmer circuit. You select what brightness you want it to run at.
Depending on what mode you select, it will give the Cree 0.7a, or 2.8a, or somewhere in between for medium setting.

Those specs are what the driver circuit feeds the LED.
Inside the lamp is going to be a circuit board which controls the LED. It takes whatever power is fed to it, and converts it to supply the LED.
This is called a Driver.

In the first listing, is states clearly that the lamp consumes 8.4 volts. The driver will convert that 8.4v to the 3.3v the LED needs.
Without knowing specifically what driver is in the lamp and what efficiency it operates at, there is no way to tell what amperage the lamp consumes.
Either way, they claim about 3-4hours of runtime at full power so that's pretty good.
And that's at full power, you can dim it to double that and still have enough light to safely navigate the streets at night.


Moving on to the second listing.
A booster circuit is a circuit designed to increase voltage. For instance, a common application is an LED flashlight that runs off a single AA.
It's takes the 1.2-1.5v of a AA battery and boosts is to the 3.3v the LED needs to work.

It's hard to tell what they mean by booster without checking out how the light works personally.
This lamp uses 3 LED's. In some cases those LED could be wired in series. Which mean you need 3 times the voltage to run them. So 9.9v.
It's seems to use the same kind of 8.4v battery pack as the first listing. So indeed, if it runs the 3 LED's in series, then yes, it would need to boost the voltage to run them . . .

However, this listing also says the available modes switch which LEDs are in operation. It seems it runs all the LED's at full power, and instead of dimming like the first light, it just turns on more LEDs if you need more lights.
A circuit that runs the LEDs in series and works the modes that way would be overly complicated for a chinese ebay special so I doubt it works that way.

It's probably runs the LEDS in series. Which means they will operate at 3.3v but consume 3 times the amperage.
In real world function, this means this lamp is 3 times brighter then the first, but will give you 3 times less runtime.
At low it would give you the same runtime as the first light will at full. At full power it will probably run less then an hour.

In which case, "booster", well honestly, I think it's just a lost in translation term and they meant to say driver.
That or it's just a sales pitch using a fancy word to market their product.
FYI, 4000 lumens seems like a bit much. A single XML is rated for 900-1000 lumens at max spec. So realistically, you're probably getting 2700-3000 lumens.
I think that might be a false claim which is not unheard of for chinese ebay special lights.

That being said . . .

I would stick with the first lamp.
900 lumens is a lot. Unless you ride offroad in the bush, I doubt you'll realistically need more light.
Even offroad, 900 should get the job done.
You'll get more usable runtime then the second light. It's overall more functional.
And more importantly, the specs of the first light make more sense the then specs on the second light.
 
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