Best driver for 1x 18650 @1.4amp (XP-G)?

M52 POWER!

Newly Enlightened
Joined
Feb 8, 2009
Messages
27
I'm building a custom flashlight with an XP-G emitter. I'd like to run the emitter up to 1.4 amps and use one 18650 cell. Are there any dirvers out capable of this? Multi mode and memory is a plus too!

-Chris
 

Fallingwater

Flashlight Enthusiast
Joined
Jul 11, 2005
Messages
3,323
Location
Trieste, Italy
I currently have an ongoing email conversation with Bryan of Shiningbeam about that driver. The specs say it's a buck/boost, but all it has are AMC7135 chips, which are buck-only linear regulators and will do no boosting whatsoever.

I have used AMC7135 drivers; they work reasonably well in a 1x18650 setup, but only if you use a low Vf LED: when the input voltage is lower than the LED's Vf, the light becomes effectively direct-driven. At a high draw, the operating voltage of a charged LiIon cell is around 3.7V and going downward; the XP-G has a Vf of about 3.3V, if what I'm reading from a quick Google search is true, so the resulting light will be regulated for... I dunno, probably about half of the battery life, and will then slowly sag.

I once made the mistake of using a 4xAMC7135 (max current 1.4A) in a 1x18650 light with a SSC P4 emitter, which has a Vf of about 3.7V. Predictably, the resulting light is practically unregulated - the driver only serves to prevent the LED from being overdriven into oblivion in the first few minutes of battery charge, and to provide multimode operation.
 

old4570

Flashlight Enthusiast
Joined
Feb 15, 2009
Messages
2,900
Location
Melbourne - Australia
There is not a lot to chose from , there are two other drivers to chose from , but there Direct drive on high ...

I use both and am happy with them , and I only just got the drivers from shiningbeam , was planning on using them with the S2 , but looks like cree is in no hurry to deliver .
 

AlexLED

Enlightened
Joined
Jul 31, 2006
Messages
238
I currently have an ongoing email conversation with Bryan of Shiningbeam about that driver. The specs say it's a buck/boost, but all it has are AMC7135 chips, which are buck-only linear regulators and will do no boosting whatsoever.

I have used AMC7135 drivers; they work reasonably well in a 1x18650 setup, but only if you use a low Vf LED: when the input voltage is lower than the LED's Vf, the light becomes effectively direct-driven. At a high draw, the operating voltage of a charged LiIon cell is around 3.7V and going downward;
...

Fully agree. AMC7135 is buck only and works quite well with 1x Li-Ion.
The AMC 7135 needs Vin of about only 0.15 volts higher than Vout for regulation:

 
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