Need help with quad cree mag 8AA

[bobli17]

I've already assembled the flashlight, but it doesn't work:thinking:. I was under the impression that I could direct drive the 4 Q4s with 8AAs but now i know i can't...:mecry:

WANTS
keep a 2D Mag size

DON'T WANTS
no li-ion batteries
no expensive drivers (fatman, shark, maxflex)
no more $$$

I can spend a little more money on a driver or drivers ~$10...

Is there anything I can do? :thanks:

 

[shakeylegs]

have you checked the continuity of the battery pack? make sure you're getting 12 V from the pack. I had one battery carrier that was not providing power - after I confirmed continuity and double checked the fit in the m@g, I cleaned all contacts and suddenly had power.

 

[spencer]

If you are using NiMH then 8*1.2=9.6volts divided by 4 emitters is 2.4 volts. Not nearly enough to light up 4 Crees. If you went with 3 emitters then that would give 3.2 volts to each LED. A Cree at 3.2 volts is about 300mA which is about 90 lumens a LED.
As to how to solve your problem, you need to get a driver or go to a 3D with 12 NiMH cells or you need 4 Li-Ion cells.

 

[Icarus]

Start saving for one if the boost drivers you mentioned!

 

[bobli17]

Thanks for the responses.

I have a few of these drivers
http://www.dealextreme.com/details.dx/sku.3256

Can I use these for my mod?? If so, how?

Can I have my batteries in series and drivers in parallel?

Option 1: 4 drivers, one to each emitter
(Will 8aa NiMH be enough juice)
Option 2: 2 drivers, one to two emitters

Option 3: HELP? (Any other BETTER ideas?)

I'm also now considering moving to a 3D Mag...

Any help is greatly appreciated. Thanks

 

[glockboy]

Option 3:
You need the "expensive drivers (fatman, shark, maxflex)".

 

[LukeA]

Thanks for the responses.

I have a few of these drivers
http://www.dealextreme.com/details.dx/sku.3256

Can I use these for my mod?? If so, how?

Can I have my batteries in series and drivers in parallel?

Option 1: 4 drivers, one to each emitter
(Will 8aa NiMH be enough juice)
Option 2: 2 drivers, one to two emitters

Option 3: HELP? (Any other BETTER ideas?)

I'm also now considering moving to a 3D Mag...

Any help is greatly appreciated. Thanks

If you switch to 3D, you can use the drivers to which you linked. ANd yes, they can be used in parallel.

 

[alphazeta]

Thanks for the responses.

I have a few of these drivers
http://www.dealextreme.com/details.dx/sku.3256

Can I use these for my mod?? If so, how?

Can I have my batteries in series and drivers in parallel?

Option 1: 4 drivers, one to each emitter
(Will 8aa NiMH be enough juice)
Option 2: 2 drivers, one to two emitters

Option 3: HELP? (Any other BETTER ideas?)

I'm also now considering moving to a 3D Mag...

Any help is greatly appreciated. Thanks

Given your constraint on using 8 nimh & the drivers that you have listed, I would go with Option #2.
The output from those drivers vary from one another & so should try to match two as close as possible with a DMM. While you're at it, try to match the forward voltages of those leds & have each pair as close as possible.
With some testing (& a little luck) hopefully you'll be able to get about 400mA to each emitter.
-AZ

 

[bobli17]

Thanks for the feedback AZ and LukeA.

I thought I did enough research to build this flashlight, but right now my newbie-ness is the only thing shining through. :duh2:

I was using modamag's Tri-Star | Quad-Lux Build Tutorial (http://www.candlepowerforums.com/vb/showthread.php?t=85713)as a reference, so right now I have the emitters connected in series, and I had a thought…

What would happen if I connect the emitters in parallel?
Could I still use direct drive?
If not, what, if any, configuration could I use with the above mentioned drivers?
Could/Should I still use 8 nimh batteries?

Sorry for all the questions, I just don't want to re-wire, de-solder and re-solder everything if it's pointless.

-Bob

 

[TigerhawkT3]

As long as each cell is averaging 1.2V or more, you should still get more than a few lumens in each emitter. With really fresh NiMHs, you could probably get around 120mA. If the emitters aren't producing any light at all, you've got either a short, an open circuit, or a dead battery.

I wouldn't recommend going parallel. If you still want to DD, go to 3D and add another three or four NiMHs.

 

[monkeyboy]

I've built the exact same light using the Fatman driver. Considering the cost of the rest of the light, the driver board is really not that expensive. I originally tried the shark but this overheats after 15 mins continuous use and cuts out no matter how well you heatsink it. The Fatman has no such problems and can be run continuously. The blue shark might also work but I haven't tried it.

Connect 8AA in series and use the Fatman to boost voltage into the 4 crees in series. I'm running mine at 825mA.

If you feel like upgrading to li-ion in the future, the light also runs on the kaidomain double D li-ion pack which gives twice the runtime of 8AA. This li-ion pack could potentially be dangerous though.

 

[Drewfus2101]

Thanks for the responses.

I have a few of these drivers
http://www.dealextreme.com/details.dx/sku.3256

Can I use these for my mod?? If so, how?

Can I have my batteries in series and drivers in parallel?

Option 1: 4 drivers, one to each emitter
(Will 8aa NiMH be enough juice)
Option 2: 2 drivers, one to two emitters

Option 3: HELP? (Any other BETTER ideas?)

I'm also now considering moving to a 3D Mag...

Any help is greatly appreciated. Thanks

Yes you can use those drivers. Wire one driver to each LED. Don't connect the LEDs to each other. Then you just need less than 9V and use that to drive all 4 drivers. You could use 6 NiMHs (7.2V - 8.1V) and be just fine. Easy.