What is the difference? Convoy M21B with 3V XHP50.2 vs M21B with XHP50.2?

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infinity
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What is the difference? Convoy M21B with 3V XHP50.2 vs M21B with XHP50.2?

I was browsing Simon’s store wanting to pick up a M21B flashlight but I came across two very similar lights and am not sure how they differ.
Links below:-

Convoy M21B with 3V XHP50.2 6500K

Convoy M21B flashlight with XHP50.2 @ 6500K

If both lights are 6500K with an OP reflector, could someone please enlighten me on how they are different, or why if one is better than the other.
Thanks.

ggf31416
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The second one with 6V XHP50.2 has a boost driver (XHP50.2 are 6V LEDs unless otherwise specified). That means that the runtime will be longer and will heat a bit less than the 3V version(which has a linear driver). The output power looks to be the same (6Ax3V vs 3Ax6V, both equal 18W).

It’s possible that the 6V version may be unable to reach turbo when the battery charge is low, that’s a common issue with boost drivers. At some point the 3V version won’t either, I’m not sure which version will reach that point first.

Overall I think the 6V version would be better.

Bort
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If you have test equipment you can buy both and experiment on them Big Smile

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infinity
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ggf31416 wrote:
The second one with 6V XHP50.2 has a boost driver (XHP50.2 are 6V LEDs unless otherwise specified). That means that the runtime will be longer and will heat a bit less than the 3V version(which has a linear driver). The output power looks to be the same (6Ax3V vs 3Ax6V, both equal 18W).

It’s possible that the 6V version may be unable to reach turbo when the battery charge is low, that’s a common issue with boost drivers. At some point the 3V version won’t either, I’m not sure which version will reach that point first.

Overall I think the 6V version would be better.

Thank you.

infinity
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Bort wrote:
If you have test equipment you can buy both and experiment on them Big Smile

No test equipment. Not even sure how to experiment. Complete novice here.

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Quote:
Infinity wrote: The second one with 6V XHP50.2 has a boost driver (XHP50.2 are 6V LEDs unless otherwise specified). That means that the runtime will be longer and will heat a bit less than the 3V version(which has a linear driver). The output power looks to be the same (6Ax3V vs 3Ax6V, both equal 18W).

It’s possible that the 6V version may be unable to reach turbo when the battery charge is low, that’s a common issue with boost drivers. At some point the 3V version won’t either, I’m not sure which version will reach that point first.”

Probable issue with the step up regulator is minimizing cost of components. Inductor, maybe output capacitor. I may learn something here. At first I thought flashlights were using linear regulators (drivers), but have seen so many comments on PWM drivers. Are both being used; linear and pwm drivers? I guess I should not be surprised.

Stan

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max
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The answers given above are correct about the drivers being different. But, let me word this a different way.

The reason for the different drivers is due to the first linked XHP50.2 is a 3V (requires 3 volts only to power it) XHP50.2 LED and Simon only offers it in 6500K. 

The second linked XHP50.2 is a 6V LED (requires 6 volts to power) and Simon offers it in 3000k, 4000k, 5000k, and 6500k. 

Personally i opted for the 4000k color temp M21B solely based on not wanting the 6500k color temp. It's all a matter of preference, I'm not a color tint snob, it's just that 4000k is much more pleasing to my eyes.  laughing

 

 

 max

ggf31416
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Quote:
At first I thought flashlights were using linear regulators (drivers), but have seen so many comments on PWM drivers. Are both being used; linear and pwm drivers? I guess I should not be surprised.

Most flashlights using 7135 chips like the older Convoy models use the 7135 to obtain the 100% mode current and then use PWM over that current to obtain the lower modes. The disadvantage is that efficiency doesn’t improve when using less than the 100% mode, the advantages are better tint consistency between modes (at low constant current LEDs get greener tint but efficiency improves) and lower cost as 7135s are mass produced parts.

The driver used in the M21B 3V uses a FET to archive linear regulation rather than 7135 chips, like the one from Led4Power, that allows obtaining the lower modes without PWM, but extra voltage is still wasted as heat like in traditional 7135 linear drivers. I wouldn’t call it a FET driver because in this community when we talk about FET drivers we usually mean the simpler, higher output ones, which let pass as much current as possible and obtain the lower modes with PWM over that huge current, resulting in poor efficiency when you don’t need turbo (more than one channel like 1+FET will improve the efficiency of this setup).