Review: Fasttech 5-mode 1xAA/AAA driver and Romisen RC-G2 mod

this is both a mini review and a mini mod, although I don’t know what mini + mini add up to :slight_smile:

bought one of these at the beginning of the year:

http://www.fasttech.com/product/1134800

as I’m a cheapskate and wanted to try out a multi-mode driver in one of my RC-G2s before slapping down 7 big ones on a much nicer 3 mode from Shiningbeam. Also, the SOS mode is a bit of piece of mind as this’ll be going into my car torch (hopefully never to be used in that mode).

Here’s the driver

a bit of the inductor plastic has broken off, but it still works fine.

here’s the old driver:

and the pill:

the pressed in brass insert has an ID of ~14mm and perhaps 0.5mm lip under that. Neither was small enough for the Fasttech driver to fit, which was ~12.5mm in diameter, so I trimmed the tabs on the driver so that they rested on the lip, then jammed in a spare piece of brass cut to fit into the gap. Lots of heat and solder gave this:

not the prettiest piece of work, but good enough. Doesn’t move either.

Thankfully it all worked too. Here are some figures:

Emitter/ tail cap amps:

original driver 0.25A / 1.86A (ratio 7.4:1) (note old meter)

new driver high 0.3/ 1.64 (5.5:1) (old meter)

med 0.11/ 0.54 (4.9:1), new readings 0.17/ 0.63A (3.75:1)

low 0.02/ 0.12 (6:1), new readings 0.1/ 0.35A (3.5:)

slightly higher high and the levels are quite nicely spaced. Med and low exhibit some high frequency whine (any tips, fujik potting?), with low at a much higher frequency. Some people might not even hear it though. Strobe = find out who in the crowd is epileptic and SOS is SOS, with a short gap between each SOS. As far as I can tell it has next mode memory (bletch), but I haven’t left it long enough to see if it just starts on high if enough time has passed. Not a major issue for its intended use, but I can see the advantage in springing an extra $4 for the SB driver (next on the list for my other RC-G2). It’ll be interesting to see if emitter amps increase with a lower Vf LED (XP-E2 NW is going in there next), like the original driver did with a Nichia 219.

Also of interest - the two lights are now more equal in brightness now that they’re both at 0.3A. XR-E has a tighter and slightly brighter spot with very little spill, Nichia has a bigger (50%?) spot and a much brighter spill.

Edited with new readings for Med and Low, which better match what my eyes are telling me :slight_smile:

Cool, thanks for the meter readings and review!

Thanks very much! Sticky’d.

ooh wow, this is my first ever sticky on a forum! I’m blushing :8)

As soon as I get the XP-E2, I’ll update the meter readings and same with the Shining Beam driver.

quick update - I sort of fixed my Fluke’s ability to read current, thanks to some help from Texaspyro, so I managed to take some emitter and tail cap readings for Med and Low. They’re now a bit more realistic (Low is way too bright for 0.02A!), although I’m currently (he he he) stymied by why I can’t read current on high. Hmm, a mystery.

When I get the time I’ll do some beamshots with the XP-E2, it’s really rather nice :slight_smile: