Mini Review Big XM-L Reflector Zhi Jun JD-9668

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Pok
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Mini Review Big XM-L Reflector Zhi Jun JD-9668

First, sorry I can't explain in English well.
So Let my pics say.

 

From http://budgetlightforum.com/node/7502

http://www.cnqualitygoods.com/goods.php?id=1358

$75 + $18.80 EMS = $93.80

Order                Ship                  Receive
02 04 2012     02 06 2012        02 10 2012


 
Mine came with dirty lens and scratch.

Pros
: Big reflector
: Direct charge plug
?


Cons
: Under-driven , Hi mode with 2x18650 tail cap current draw 920mA
: Bad heatsink
: Too long


Lens = around 70mm
Reflector = out/in 70mm/65mm  , length around 71mm
Switch = Electronic switch
Mode = Hi Lo Strobe
Battery = 2000mA , 70mm long

I tested from 4.20V discharge to 3.0 V current 1.0A = 2069mA not bad.


Tali Cap current
2xTrustFire Flame 4.15V  4.15V
Hi = 920 mA  >>> very disappointed
Low = 250 mA  

@ 3.94V 3.94V Hi mode = 990mA

Lux
2360 @ 4 meters =   37760 lux ANSI

My mod did 78kcd with U2 and about 3.6A to LED.



OK done, prepare to mod with U2 and some driver.

 

 

 

Bad heatsink

Edited by: Pok on 05/08/2012 - 09:40
Pok
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Reserve for beamshots.

BetweenRides
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Very handsome light. Look forward to seeing more. How does it throw out of the box?

Ledsmoke
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almost like a Trustfire X9 Sad

~ Ledsmoke ~

Dutch humor:

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weiser
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You're absolutely certain it's driven under 1A? That's terrible. This should definitely be driven over 2A. What a waste. 

 

Considering the dirty lens and scratch, you could make a case for a defective product considering <1A definitely isn't producing anywhere near the 850 advertised lumens. 

Chicago X
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Please remember that the current draw was measured with 2 cells.

http://wardogsmakingithome.org/index.html

War Dogs, Making it Home - Rescue Dogs for Returning Vets

Pok
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weiser701 wrote:

You're absolutely certain it's driven under 1A? That's terrible. This should definitely be driven over 2A. What a waste. 

 

Considering the dirty lens and scratch, you could make a case for a defective product considering <1A definitely isn't producing anywhere near the 850 advertised lumens. 

It's 920mA with 2x18650 @ talicap draw = around 1.8A - 2.0A to LED

weiser
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I totally spaced on that!

 

makapuu
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Anxious to see when you bring it up to potential.

Did they glue any of the threads ?

Pok
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makapuu wrote:

Anxious to see when you bring it up to potential.

Did they glue any of the threads ?

No, no glued threads.

edc
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Have you tried better batteries?

 

http://i1193.photobucket.com/albums

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edc wrote:

Have you tried better batteries?

It's about driver sure, not my battery TF flame , Shoshine , 2000mA include , etc...

Richie086
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Hi Pok, did you ever get to do the LED and driver upgrade to this light.  From your tail-cap readings, I calculated about 2.23a input to the LED, then whatever the losses would be. I'm curious how much you were able to improve it. 

Richie

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Pok wrote:

weiser701 wrote:

You're absolutely certain it's driven under 1A? That's terrible. This should definitely be driven over 2A. What a waste. 

 

Considering the dirty lens and scratch, you could make a case for a defective product considering <1A definitely isn't producing anywhere near the 850 advertised lumens. 

It's 920mA with 2x18650 @ talicap draw = around 1.8A - 2.0A to LED

Still extremely under driven and nowhere near the claimed output in lumens. I'm very surprised that the heatsinking is poor.  In the photos on Ric's page the heat sink looks positively beefy.  For the money you payed for this light you shouldn't have to invest another $15-$20 in a new emitter and driver to make it right.

Did you ever finish this project?

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Richie086 wrote:

Hi Pok, did you ever get to do the LED and driver upgrade to this light.  From your tail-cap readings, I calculated about 2.23a input to the LED, then whatever the losses would be. I'm curious how much you were able to improve it. 

Richie, how exactly do you perform your calulations?  This uses a buck circuit, not a boost. I'm not sure how you generate additional energy than even the batteries are pushing on top of driver loss due to ineficiency to end up with 2.23A at the LED.

I figure around 1840mA (920mA x 2) to the driver, minus about 15% driver loss (assuming it's a decent driver, and I doubt it is) putting about 1.54A to the LEDs minus the additional losses by reflector and lens ending up with 500 lumen on it's luckiest day.

Richie086
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JohnnyMac wrote:
Richie, how exactly do you perform your calulations?  This uses a buck circuit, not a boost. I figure around 1840mA (920mA x 2) to the driver, minus about 15% driver loss (assuming it's a decent driver and I doubt it is) putting about 1.54A to the LEDs minus the additional losses by reflector and lens ending up with 500 lumen on it's luckiest day. [/quote]

 

I missed the Buck circuit part.

I used the formula below:

.920mA * 8v = 7.36

7.36/3.3 = 2.23a

 

I also just noticed the pill is a drop-in on this light, not great.

Richie

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It's 920mA with 2x18650 @ talicap draw = around 1.8A - 2.0A to LED

2x18650 @ 8.38V no load

920mA x 7.8-8.0V with load around 1-2 min = 7.36W

While Vdrop @ LED is about 3.1-3.2V @ 7.36W = 2.3A

15% driver lost , total about 2A to LED

Sorry, for my English.

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FYI

It's a hollow pill , not a massive pill.

I forgot to take pic inside the pill

ergotelis
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Well the best way to measure efficiency, by the time you are going to swap a U2 led, is to cut the wire on the led and measure there the current that goes to the led with a multimeter, to be sure.

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Richie086 wrote:

JohnnyMac wrote:
Richie, how exactly do you perform your calulations?  This uses a buck circuit, not a boost. I figure around 1840mA (920mA x 2) to the driver, minus about 15% driver loss (assuming it's a decent driver and I doubt it is) putting about 1.54A to the LEDs minus the additional losses by reflector and lens ending up with 500 lumen on it's luckiest day.

 

I missed the Buck circuit part.

I used the formula below:

.920mA * 8v = 7.36

7.36/3.3 = 2.23a

 

I also just noticed the pill is a drop-in on this light, not great.

[/quote]Nice, thanks for the info.  I never take into account the additional voltage above what the LED uses when calculating.  That would explain why you have more going into the LED than coming out of the battery.

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ergotelis wrote:

Well the best way to measure efficiency, by the time you are going to swap a U2 led, is to cut the wire on the led and measure there the current that goes to the led with a multimeter, to be sure.

Yes, I measured like your said for many time,

But I disappointed this driver, So I din't test more.

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The formula below I used, I thought this calculates the actual total current at the tail cap or input voltage reading from a DMM at the tailcap, which is .920mAh on HIGH mode?  But I didn't subtract the 15% for losses from the 2.23a number, which I mentioned above.   But even though the batteries are rated at 2000mAh, they could still be higher or lower than what's printed on them. 

Was this the correct formula for this light or should I have calculated it another way?  Thanks  

 

.920mA * 8v = 7.36

7.36/3.3 = 2.23a

Richie

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Pok wrote:

FYI

It's a hollow pill , not a massive pill.

I forgot to take pic inside the pill

What a shame.  So much potential wasted with this light.  Crazy over priced for what you get, IMO. Frown
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Richie086 wrote:

The formula below I used, I thought this calculates the actual total current at the tail cap or input voltage reading from a DMM at the tailcap, which is .920mAh on HIGH mode?  But I didn't subtract the 15% for losses from the 2.23a number, which I mentioned above.   But even though the batteries are rated at 2000mAh, they could still be higher or lower than what's printed on them. 

Was this the correct formula for this light or should I have calculated it another way?  Thanks  

 

.920mA * 8v = 7.36

7.36/3.3 = 2.23a

 

@3A about 3.2-3.5V

@2A about 2.9-3.2V