Hi there, Do you think this flashlight have over 3000lm ?

[minos2014]

Hi there, Do you think this flashlight have over 3000lm ? and the price is fair.I want to buy this one for test .
Aliexpress.com : Buy underwater photography light/primary dive light 3000lm free shipping from Reliable light blue high heel suppliers on ShenZhen E-Better CO.,Ltd

 

[Diver0001]

To the best of my knowledge with current technology a 15 watt LED bulb (or system of bulbs) will not generate 3800 lumen. It would take a bulb (or system of bulbs) with round about 40 watts.

Since there are 4 bulbs in it then it's theoretically possible for them to be running EACH of them at 15 watts but I'm still not convinced that it would generate 3800lm together. Moreover, if this is what they're really doing then it's going to need a bigger battery.

R..

P.S. That doesn't mean that the manufacturer is necessarily lying. Some very efficient LEDs can *theoretically* produce upto about 250 lumen/watt under some cirtumstances. For example, if the bulb is cooled to very low temperatures with liquid nitrogen and then blasted with a high levels of power and measured (just before it explodes). What this manufacturer has probably listed is the theoretical top power measured in such an experiment. Realistically the power will be no where near that in real world circumstances.

Most LED dive lights on the market right now generate between 50 and 100 lumen per watt and you can even ask yourself is that number was measured or calculated.

 

[dfx]

Cree Component XLamp XM-L LEDs

Rated at 1040 lumens at 10 watts. So theoretically, 4 of them can produce 4160 lumens if you're able to deliver the required current and do everything else right. I suppose you can overdrive them too to get even more, but let's go with those numbers for now.

26650 batteries max out at 3.7 V but on average run at around 3.2 V. At 3.2 V, you'd need 3.1 A per LED, which means that in this configuration, each battery needs to sustain 6.2 A. All this assuming "best case" according to manufacturer ratings.

Now it will depend on whether or not your batteries are up to the job. From googling around, it looks like many 26650 batteries have their maximum sustained discharge current rated at or beyond 10 A, while others (due to the PCB?) only give you something like 4 A, so YMMV.

So, theoretically plausible given the right batteries. How the light actually performs is a different question. The "15 watts" makes me somewhat suspicious, because even if that's 15 W per battery, that still leaves you short by a couple of A.

 

[minos2014]

To the best of my knowledge with current technology a 15 watt LED bulb (or system of bulbs) will not generate 3800 lumen. It would take a bulb (or system of bulbs) with round about 40 watts.

Since there are 4 bulbs in it then it's theoretically possible for them to be running EACH of them at 15 watts but I'm still not convinced that it would generate 3800lm together. Moreover, if this is what they're really doing then it's going to need a bigger battery.

R..

P.S. That doesn't mean that the manufacturer is necessarily lying. Some very efficient LEDs can *theoretically* produce upto about 250 lumen/watt under some cirtumstances. For example, if the bulb is cooled to very low temperatures with liquid nitrogen and then blasted with a high levels of power and measured (just before it explodes). What this manufacturer has probably listed is the theoretical top power measured in such an experiment. Realistically the power will be no where near that in real world circumstances.

Most LED dive lights on the market right now generate between 50 and 100 lumen per watt and you can even ask yourself is that number was measured or calculated.

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Yes . You are correct.
But i think the price is attractive.I just wonder how long it can runs .
4pcs 18650 maxminum 3400mah*4=13600mah.
I guess this light is two chips in series and two chips in parallel,i think the vendor should advertize the inside connections.[FONT=Tahoma, Arial]
[/FONT]

 

[yaronad]

Cree Component XLamp XM-L LEDs

Rated at 1040 lumens at 10 watts. So theoretically, 4 of them can produce 4160 lumens if you're able to deliver the required current and do everything else right. I suppose you can overdrive them too to get even more, but let's go with those numbers for now.

26650 batteries max out at 3.7 V but on average run at around 3.2 V. At 3.2 V, you'd need 3.1 A per LED, which means that in this configuration, each battery needs to sustain 6.2 A. All this assuming "best case" according to manufacturer ratings.

Now it will depend on whether or not your batteries are up to the job. From googling around, it looks like many 26650 batteries have their maximum sustained discharge current rated at or beyond 10 A, while others (due to the PCB?) only give you something like 4 A, so YMMV.

So, theoretically plausible given the right batteries. How the light actually performs is a different question. The "15 watts" makes me somewhat suspicious, because even if that's 15 W per battery, that still leaves you short by a couple of A.

Do you think/know if batteries like that :

2pcs 5000mAh 3.7V TrustFire 26650 Rechargeable Li ion Lithium Battery with PCB-in Consumer Electronics on Aliexpress.com

Watts = Volts x Amps
3.2 X 5A = 15A
(and you have 2 batteries)

...- can actually make it work ? as expected?

even close to that = is GR8 price/deal....no?


.

 

[yaronad]

Do you think/know if batteries like that :

2pcs 5000mAh 3.7V TrustFire 26650 Rechargeable Li ion Lithium Battery with PCB-in Consumer Electronics on Aliexpress.com

Watts = Volts x Amps
3.2 X 5A = 15A
(and you have 2 batteries)

...- can actually make it work ? as expected?

even close to that = is GR8 price/deal....no?


.

Anyone can answer

 

[eelnoraa]

Do you think/know if batteries like that :

2pcs 5000mAh 3.7V TrustFire 26650 Rechargeable Li ion Lithium Battery with PCB-in Consumer Electronics on Aliexpress.com

Watts = Volts x Amps
3.2 X 5A = 15A
(and you have 2 batteries)

...- can actually make it work ? as expected?

even close to that = is GR8 price/deal....no?


.

5000mAh is not a spec for max sustained current load. This is actually an unit for the capacity of the battery. 5000mAh x 3.7V = 18.5Wh that is how much total energy the battery can store. No where in this unit, or in the product spec says this battery can supply 5A tho. All it means IF it is able to supply 5A, it will last 1 hour.

 

[Issue]

Just want to add that 18650 batteries rated to 5000mAh is way overrated and probably pure crap. You will probably get more power out of a 18650 rated to 2600mAh. Dont fall for thoes "fake" specs..

 

[scubastingray]

Just want to add that 18650 batteries rated to 5000mAh is way overrated and probably pure crap. You will probably get more power out of a 18650 rated to 2600mAh. Dont fall for thoes "fake" specs..

Those are 26650s, bigger batteries. I'm not saying TF batteries capacity specs are true, but it's a little different from 18650s.

 

[snowblind80]

Do you think/know if batteries like that :

2pcs 5000mAh 3.7V TrustFire 26650 Rechargeable Li ion Lithium Battery with PCB-in Consumer Electronics on Aliexpress.com

Watts = Volts x Amps
3.2 X 5A = 15A
(and you have 2 batteries)

...- can actually make it work ? as expected?

even close to that = is GR8 price/deal....no?


.

Way too much of a good deal. I got some 18650 trustfire batteries from aliexpress with a charger. The batteries were no where near the rating and when I took the wrapper off them it looked as if they were old cells that had been rebranded.