Looking for a modder for First Light USA

I have a First-Light USA MC and NV 425 that aren't getting any use.
Looking for someone who can bore the battery tube, head, and tailcap to 18mm diameter as a trial project. I ve considered 18650 battery use but the voltage isn't enough so I m now considering 2x 18350. Not sure how this might pan out but any thoughts or concerns I m all ears.

These topics usually run in "Homemade and Modified" .... Thread moved.

Thanks I wasn't sure

I dunno, unless you already have some 18350s I wouldn't bother. Sure they might give you up to a 30% increase in run time vs. 16340s and about the same from lithium primaries ...maybe, but the cost of getting it bored and the new cells...is it worth it? Are they not getting used because of the battery type or some other reason?

Tired of running 16340's down.... spoiled by HDS 1 cell 16340 runtime

Too bad no one has come up with a Li-Ion, six volt cell to replace double 123As and is of decent capacity. Also too bad that First Light doesn't seem interested in embracing rechargeable cells. With what they charge for these lights, I guess they don't have to.

Yeah it's a bit sad. The MC is a modded nichia b with approx 500 lumens... gorgeous tint and I have some custom titanium tubes I could experiment with but the tailcap, the head are the main issues plus boring enough of the tube without cutting into the threads. It would be close I think

usdiver said:

Tired of running 16340's down.... spoiled by HDS 1 cell 16340 runtime

Click to expand...

isnt the difference in runtime directly related to the difference in output?
the HDS 250 makes just 166 lumens after step down

while the FL makes 3-4x more lumens.. so of course they use batteries faster.. no free lunch

one of my concerns is that you are considering running two LiIon cells in series. Do you realize there are risks associated with mismatched voltages? be careful

some data on battery capacity
two CR123 = 3000mAh
two 16340 = 1300mAh
two high cap 18350 = 2200mAh
one 18650 = 3600mAh

seems to me, if you like the HDS output, that an 18650 tube would give you the longest runtime, for use in the HDS, not in the FL, which as you pointed out, needs to see more voltage..

from where I sit, if you want a dual 18350 tube for your FL, it might make sense to just have a tube made from scratch, rather than risk damage to a stock tube, from boring it out..

I hope you find a solution that works for your needs

Thanks Jon I agree with you but the real challenge is boring the head as the head area is only larger enough for the 16340's unless possibly could use a spacer but I m not liking that idea.
The tailcap presents another challenge and so forth but I d be willing to do it if I could get more juice out of it.

The way it's looking however is it's going to be a no go. My 219b Mc is already a mod but it's quite useful so I was considering my nv.
I hear First light designed these for entities that had a running supply of cr123's but I don't know for sure

Government contract I'm sure. Which is probably the reason for the lack of change and the reason for the high prices. Although I've never heard of their lights being used by actual troops...it's not an impossibility.

You are likely correct about the contract but I have seen us gi issue sales on some of these and some of these look like they've been in battle and they still work.
They are among the best lights I ve had but still aren't that popular however the T Max LE 700 is a true life saver if you do any security or police work involving traffic. The platform itself is really good hence my urge to improve.

jon_slider said:

some data on battery capacity
two CR123 = 3000mAh
two 16340 = 1300mAh
two high cap 18350 = 2200mAh
one 18650 = 3600mAh

Click to expand...

Be careful of this one. You can only directly compare mAh with cells of the same chemistry. You should convert to watt hours instead.

On top of that adding cells in series does not add their mAh but instead their voltage. Where as adding them in parallel adds their mAh but not voltage.

How you access that energy is also important. If you have a single 3v class LED having two cells in parallel is better as the voltages more closely match the LEDs meaning it will be more efficient no matter what type of regulator you use.

staticx57 said:

Be careful of this one.

Click to expand...

thank you!

like this?
two CR123 = 1500mAh x 6v = 9000
two 16340 = 650mAh x 7.4v = 4810
two high cap 18350 = 1100mAh x 7.4v = 8140
one 18650 = 3600mAh x 3.7v = 13320 (but not enough voltage for FirstLight)