Which driver for 2 x NIMH

[BigBoy]

HI,

I purchased a SSC P4 emitter with a Mag C heatsink from LITEmania. Now I need a driver board to run the P4 a 1000 ma. It seems that there are 2 drivers:
1) BB Nexgen 1000
2) GD1000 buck/boost
I am planning on getting the GD1000, but it would be nice to have an expert comment on this choice.

Thanks ...

 

[LED Zeppelin]

I'm no expert, but I did notice this note regarding the NG1000:

Note1: Safe mode is ~1.5A input current. If output doesn't go into full regulation it falls back to safe mode. For a Nexgen 750mA or Nexgen 1A, this critical starting voltage is ~3.4V. Input voltages above this will start the regulator into full constant current regulation and it will regulate down to ~2V input. A Nexgen 500mA will almost always start in full regulation mode.

Personally I would go with the regular BadBoy 1000. It can take a lower input voltage, 1.6 vs. 1.8V. The GD may be a bit nore efficient, but you don't need the buck feature of the GD unless someday you use a different cell solution. Another cell option for the GD would be a single Li-ion cell and a spacer or dummy cell.

With the BB, your Vin should be less than the Vf of the emitter, and you'll be fine with your plans. With the GD Vin could be as high as 5.4 volts.

Here's a link to the BB Blank. You need to select R1 = R2 = 0.10 ohms to yield a 1000mA drive current.

http://theledguy.chainreactionweb.com/product_info.php?cPath=48_49_61&products_id=179

Hope this helps.

 

[PhotonAddict]

I think even the BadBoy is limited to a max input of 1.5A (Techinical Converter Info ) At 1A you would be driving an SSC at almost 4W, assuming an efficiency of ~80% you would have to draw approx. 1.9A from a 2.4V source.
There have been some posts in this forum about using drivers in parallel - 2xMadmax+ would be too much but 2xNexgen500 might work but I've never tried it and I'm not sure if current regulation would work in that situation. If it is o.k. with a Downboy, it might work with the Nexgen. Perhaps Wayne can offer some insight?

Some threads of interest:
http://www.candlepowerforums.com/vb/showthread.php?t=124476&highlight=parall%2A
http://www.candlepowerforums.com/vb/showthread.php?t=123331&highlight=parall%2A
http://www.candlepowerforums.com/vb/showthread.php?t=155687&highlight=parall%2A

 

[BigBoy]

LED Zeppelin and PhotonAddict THANKS! for your reply's. I am starting to understand the issues involved.

I was inspired by the following post to do a mod myself (not knowing the issues involved with drivers):

http://www.candlepowerforums.com/vb/showthread.php?t=155653

Malkoff devices is modding 2 C maglites (as well as other configurations). He is using a MAX1763 IC with the current is set at 1000ma. I was wondering if the Sandwich Shoppe has a driver with similiar specs. If not I may need to use a 3 cell host to simply the problem.

 

[LED Zeppelin]

You can use 3C cells in a 2D host and make an adapter sleeve from a section of PVC tube.

I did this and had to buy a 6' length of tube. Needless to say I have more than 5' left over and would be happy to send you a section if you want to try it out.

Send me a PM if you're interested.

What PhotonAddict said makes sense, you might be better off with 3 cells.