View Full Version : Petit Crouton with Boost Regulation?

01-20-2012, 10:50 PM
Anyone know if the latest version of the PC (Ver 1.6) supports boost regulation? I could have sworn I read that it does now, but haven't been able to rediscover that post after much searching. I'd like to use a 7.4 volt pack to run a series wired amber LZ4 at 1.5A, but that would require around 12v (18W) out of the PC. I read the updated PC 1.6 manual that Tim posted, but didn't see max output voltage specs or even max power rating listed.

01-21-2012, 03:01 AM
Power supply: 4.5 to 9 V / 2A (with the High-power LED). 2 li-ion cells (18650 or 14500) batteries recommended. copied from page 4 of the manual.
this thread should help with the wiring http://forums.thecustomsabershop.com/showthread.php?13703-LEDengin-5w-and-10W-info-and-wiring-guide....for-noobs

01-21-2012, 03:28 AM
Thanks, but those specs aren't what I need and I already read through that link long ago. Unfortunately it only addresses the parallel-series configuration, which limits current to 2A total or only 1A per pair of dice if driven directly by the PC Ver1.6. I want to run all 4 dice in series at 1.5A, which would require about 12 volts total output to satisfy combined VF. If the PC is buck regulated only, the best I can get from the output would be less than 7.4V and I'd have to employ a power extender or relay to drive the LED at 1.5A. If boost regulated and capable of at least 18 watts then I'm in business with driving directly from the PC. Anyone know if the PC V1.6 is boost regulated?

01-21-2012, 09:52 AM
The pc is a buck only driver. No boost. That would be cool though. The easiest way to put that much power to a 10w would be to run the dice parallel and use a seperate driver (see my Praxis saber build).

01-21-2012, 07:14 PM
Thanks Sunrider - your Praxis is incredibly beautiful btw. Did you make the 6.6A driver yourself? I'm still inclined to run all 4 dice in series, but if I can't find a a boost regulator with small enough footprint maybe I'll cheat and use a 14.8V pack and resistor or equally inefficient LM317 constant current circuit.

01-21-2012, 07:59 PM
I can tell you where to get that driver. I did not make it. Boost setups are much more complicated and need more space. Parallel 10w pcbs can be found so that makes such setups so much easier. With the pwm input you get effects. You wont get 12bit pwm control with the 317. ;)

01-22-2012, 10:19 AM
I'm definitely interested in getting the driver - the store only lists 1.5A versions. I saw something similar on KD, but was sold out. The reason I'm shying away from a parallel LZ4 setup is the 3+ Amps I'd have to pull from the batteries to power it. In series, I'd only need half the current for the same brightness. Theoretically the power requirements would be the same because of the higher voltage, but in practice the higher current requirements of the parallel config would result in greater heat losses and wear/sag on the 14500s I plan to use, plus it's kinda hard on 26g wire. I had issues with spring retention battery holders turning into toaster coils under high current draw before I started using battery packs for these leds - not fun.

01-22-2012, 11:43 AM
In series 4 green dies have a vf of 16 or 17v. Then you would need 6 li-ions for a 20v pack. Protection pcbs are MASSIVE at that voltage. From actual "practice" , ;) Trust me when I say 2 18650s and parallel dies is the way to go. 24 or 22 gauge can work for 6 amps. Heat loss is minimal, the 6 amp driver is 85% efficient. Always make a pack btw. Taskled has the driver.

01-22-2012, 11:54 AM
When we get the CC drivers back in stock if all goes well they will be a 3A driver.

01-22-2012, 12:56 PM
When we get the CC drivers back in stock if all goes well they will be a 3A driver.

Now that's what I'm talkin about. :cool: This will open up some new possibilities.

Rhyen Skytracker
01-22-2012, 09:24 PM
When we get the CC drivers back in stock if all goes well they will be a 3A driver.

thanks Tim. :D

01-22-2012, 10:40 PM
Awesome news about the 3A drivers - that's definitiely a game changer in favor of a series/parallel approach for these leds, as was Sunrider's driver. My LZ4 is amber so it only needs about 12V forward to make 1.5A which I can do with four 14500s in shotgun formation and still fit in a standard hilt with speaker, sound card, and other electronics. Not sure how to fit more than one 18650 without extensions or other modifications, but I have to agree that a series approach isn't going to work either if a 20V pack is required. Just curious Sunrider, when you run the Praxis upwards of 6 amps, how much voltage sag are you getting from the 18650s? Did your voltage ever dip below driver or sound card thresholds when using fully charged cells? IMRs wouldn't have a problem, but I'm curious how regular cobalt li-ions did since alot of them list around 5 Amps as maximum drain. Thanks so much for your time and recommendations in these posts. I value your expertise and appreciate the information so generously given. Many thanks.

01-23-2012, 07:17 AM
The 4 pack can be done, but no soundboards will handle that voltage. The components I use only need 5v to function so no problem there. Some batteries sag bad when you push them near their current limits. I use NCR 18650s. They are much better under load. 2 can do 10 or 12 amps at 4v continuously. They have much higher capacity than anything else also. They are tricky to fit but necessary for my high power setups.

01-23-2012, 01:10 PM
Thanks for the info. I wasn't sure if the h6flex would still work at 5V under high load since the webpage sort of indicates a minimum input of 7 volts. Also, I'm going to have to look into those NCR cells for a flashlight mod I've been tinkering with. I was under the impression that NCR/NNP gave you greater capacity at the expense of discharge rate, but 10A in a higher capacity 18650 is no compromise. Are you using Pany branded or AW or Redilast? I haven't wired a soundboard yet, but I was thinking about tapping half of the four 14500 pack to power a PC at 7.4V. I think this would be the simplest approach so long as I can isolate grounds. Have any expereince or thoughts/cautions doing this?

01-23-2012, 01:24 PM
Tapping into a pack like that is dangerous don't do it. I would try to run a soundboard off a regulator if I had to, but here we go again with heating problems from the voltage difference. ;) The NCR batteries are better in all respects to others. The AW and others that use the NCR18650s are protected. I use the plain Panasonics with tabs so I can make a proper pack with the proper voltage PCB.