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freeme
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Included.

wellerus wrote:
Is it adapter for 18650 battery included or not?

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Anthon
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just received two units of this light

I only get 2200lm with both lights

I know there was a problem with the driver from the first c8f 21700 that didn’t reach the claimed lumens, and sofirn released a second version of the driver

Maybe this light is using the first underpowered driver?

JasonWW
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Anthon wrote:
just received two units of this light

I only get 2200lm with both lights

I know there was a problem with the driver from the first c8f 21700 that didn’t reach the claimed lumens, and sofirn released a second version of the driver

Maybe this light is using the first underpowered driver?


I don’t think there was ever any problem with the driver. There might be a lack of current flow through the retaining ring. Maybe glue on the threads? Adjusting it gave me a boost in output. Also changing the led wires can give a boost.

It will not hit 3500lm stock. I think they over rated it. About 3,000lm stock seems right.

Being a FET driver, the output can vary a lot based on the battery. What battery are you using? How are you measuring the lumens?

freeme
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Both Sofirn and GearBest have confirmed that Utorch C8F will not have previous Sofirn issue. My C8F from very first batch did produce 3300lm with my VT5A.

 

Anthon wrote:
just received two units of this light I only get 2200lm with both lights I know there was a problem with the driver from the first c8f 21700 that didn't reach the claimed lumens, and sofirn released a second version of the driver Maybe this light is using the first underpowered driver?

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Anthon
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JasonWW wrote:
Anthon wrote:
just received two units of this light

I only get 2200lm with both lights

I know there was a problem with the driver from the first c8f 21700 that didn’t reach the claimed lumens, and sofirn released a second version of the driver

Maybe this light is using the first underpowered driver?


I don’t think there was ever any problem with the driver. There might be a lack of current flow through the retaining ring. Maybe glue on the threads? Adjusting it gave me a boost in output. Also changing the led wires can give a boost.

It will not hit 3500lm stock. I think they over rated it. About 3,000lm stock seems right.

Being a FET driver, the output can vary a lot based on the battery. What battery are you using? How are you measuring the lumens?

Even Sofirn told that there was some problems. I tried with an Acebeam 21700 cell and a Sony VTC6. I measure them in my integrating sphere

Sofirn wrote:
I know some of them, 30% of the inventory, don’t reach the max 3500LM, and that’s why the price is low. We promise a new driver for you to replace.
Sofirn wrote:
Hey guys, sorry that C8F 21700 version has this issue. I was told it’s caused by MOS component. I don’t know what MOS is but I would love to send new driver to whose C8F max output lower than 3000 Lumens via 21700 battery
JasonWW
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I was the one who told Sofirn I suspected there was a problem with their original driver since output was low and it would not pull many amps. Possibly a FET with too high resistance. Their second driver version using a new FET had the same performance. Sick

I then told them that there seemed to be something about the retaining ring that was not getting good contact. I never heard back from them other than they would tell their engineers. Maybe they tweaked the retaining rings to get a better connection? I don’t really know.

What type of integrating sphere do you have? Do you think it’s accurate?

Have you tried measuring the amp draw across the tail cap?

Mtonne
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My C8F was underwhelming as well. I chalked it up to the 30qs I was using and ordered a 21700 for it. We shall see if that helps.

Anthon
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JasonWW wrote:
I was the one who told Sofirn I suspected there was a problem with their original driver since output was low and it would not pull many amps. Possibly a FET with too high resistance. Their second driver version using a new FET had the same performance. Sick

I then told them that there seemed to be something about the retaining ring that was not getting good contact. I never heard back from them other than they would tell their engineers. Maybe they tweaked the retaining rings to get a better connection? I don’t really know.

What type of integrating sphere do you have? Do you think it’s accurate?

Have you tried measuring the amp draw across the tail cap?

I’ll check the retaining ring and measure amp draw tonight

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