Quite honestly, this little light (although cool), is not really that great for a high power laser mod. I only showed this because Kip Kay had a piece of junk build that was getting too much attention, and I wanted to show how to do it correctly.
For my build, a 14650 is the largest battery it will fit...
But for 1 Watt neighborhood:
I would recommend 1 Amp with a 445 diode. Which would be 1 Watt with a 405-G-1 glass lens. But about 875mA's with an AixiZ 445 lens.
The AixiZ 445 lens gives a better looking dot with this multimode diode at about 15 to 20% less power than the 405-G-1. See lens comparisons here:
http://laserpointerforums.com/f65/445nm-a130-lens-comparisons-51456.html
Even so, 875mW's is very bright and dangerous too. Proper eye protection is a must. It will instantly damage the eye with a direct shot or even a reflection off a shiny object.
Also, spend the extra money on a quality AW brand 18650 battery:
AW 18650 Protected 2600 mAh Rechargeable Lithium Battery
Any of my 18650 kits will do fine with a 1 Amp setting. It's just a matter of which one 'tickles your fancy'. But I do not include diodes. You can get the 445 diode here:
http://laserpointerforums.com/f39/445nm-diodes-stock-xj-a140-52076.html
People are pushing these diodes to 1.6 Amps and beyond. So I have some new 'monster build' kits using large Maglights. My newest one will be a Maglite 2 D using 2 X 32600 Li-Ions with a FlexModP3 driver:
http://laserpointerforums.com/f64/fs-large-maglite-kits-side-button-forward-clicky-57278.html
More normal kits below:
Here are my 18650 kits: (several options to look through, heatsink material, lens options, EzFocus adapter, etc…)
The easiest assembly kits, are my SolarForce L2P, and my Black 18650 kit…
Black 18650 kit: (easiest assembly)
http://laserpointerforums.com/f64/fs-18650-build-kit-easy-assembly-445nm-blu-ray-red-43857.html
Stainless Steel 18650 kit:
http://laserpointerforums.com/f64/fs-stainless-steel-18650-kit-polished-perfect-445-a-52159.html
SolarForce L2P kit:
http://laserpointerforums.com/f64/fs-solarforce-l2p-kit-18650-host-massive-heatsink-53746.html
X2000 Focusing Head 18650 kit:
http://laserpointerforums.com/f64/fs-x2000-focusing-head-18650-kit-55246.html
P19 Focusing Head 18650 kit:
http://laserpointerforums.com/f64/fs-p19-focusing-head-18650-kit-very-nice-host-57115.html