Review: C20 DIY EDC flaslight host from FastTech

Flashlight Modding and DIY Parts
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FastTech C20 DIY EDC LED Flashlight Host

Summary:

Battery: Single 18650
Switch: Reverse clicky
Modes: Any you like!
LED Type: None
Lens: Glass non/AR
Tailstands: Yes, after mod
Price Paid: $6.65 before discount
From: FastTech
Date Ordered:

Pros:

  • Good quality machining
  • Nice anodizing, very pleasant shade of gun-metal gray
  • Fits protected cells
  • Reflector works well with XM-L emitter
  • No sharp edges, crenelations, or coarse knurling to wear out pockets
  • Takes standard 16mm emitters and 17mm drivers

Cons:

  • Slight blemish on the reflector (doesn't affect beam/use)
  • Slightly too large for an EDC
  • Smooth finish, not very grippy
  • Longer driver spring or tailcap mod needed to use Nangj driver with unprotected flat-top cells
  • CREE branding etched onto side panels - Sorry Nichia modders...

Just a bit about this light:

I purchased it a few weeks ago from FastTech. This unit has the SMO reflector...

http://www.fasttech.com/products/1618/10002463/1181700-c20-diy-edc-led-flashlight-host-for-cree-xm-l

...but the same kit with the OP reflector is available as well:

http://www.fasttech.com/products/1618/10002463/1198400-18650-diy-edc-led-flashlight-host-with-switch-refl

The specs on the FastTech website were correct as the light measure 115mm x23mm dia. as stated.

I assembled this light using an XM-L U2-bin emitter and 2800mA Nanjg 105c driver:

The driver was set to the 2-mode High/Low configuration. The Low mode on this driver is far too high for normal around-the-house use, and could benefit by having a moonlight mode. On high, this light is extremely bright, but understandably floody due to the small diameter reflector.

Although this form-factor is referred to as an EDC, I find this light slightly too large for that purpose. It is easily small enough to drop into a pocket if I need more light or longer runtime than my EDC can provide, but is just to heavy for EDC pocket carry. The TrustFire F20 I am currently using as my EDC is much more convenient and unobtrusive:

I like this as a go-to household light as it is compact and can be dropped in a pocket if needed, and the low mode provides sufficient illumination for normal everyday tasks. High mode is available, and with the 2800mA drive I chose, pushes the LED very hard for this small host blasting a wall of lumens, but at the expense of rapid heat build up. The pill obviously does a good job of tranferring heat into the body of the host, but with the small amount of mass available, this light rapidly heats up. I've only left it on high for a few minutes while holding it in my hand, but I'm sure it would get untouchably hot very quickly if left unattended for an extended time.

The small-sized stock spring on the Nanjg 105c driver prevents shorter non-protected flat-top cells from making good contact. The light works properly, but any shaking will break the connection making the light change modes. As the light comes assembled, the tailcap boot protrudes beyond the end of the light preventing tailstanding. I removed the boot and did the o-ring mod. This had the double-improvement of both recessing the tailcap to allow tailstanding and also tightened battery connection so my cells work properly now. Both my laptop salvage Sanyo cells and Protected Trustfire cells fit.

Overall, I do like this light as a pick-up-and go light, but it doesn't have much advantage over a P60 host. I won't be using it as an EDC, but it's great for quick tasks outside at night, tailstanding on low for use in power outages, or keeping by the bedside. It's a good option for someone wanting to get into flashlight modding/building as it's easy to work with and has everything you need to use with your own emitter/driver combo.

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Nice review. Thank you keltex78.

Well put about it’s EDC limitations (applies to all the 18650 tube lights). I find myself so wanting to EDC so much power and capacity (mostly in the winter), but it just stands out so much in an office environment for me.

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Thanks for your review keltex!

-Garry

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thanks for the review Keltex, I have one of these on the way too (OP though). If I don’t like the beam, hopefully a 20mm TIR will drop right in. Good tip about the tail cap mod, but what does it consist of exactly? Putting an o-ring between the boot lip and the tail cap to raise the switch and boot inside the light? I don’t really need it to tail stand, but I will be using a variety of cells with it so a stronger connection would be helpful.

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That's correct on the tailcap mod. I actually cut the lip from another discarded tailcap boot and used it since I didn't have an actual o-ring of the appropriate size. You just need a ring that will fit around the end of the tailcap but not roll past the lip. That will move the boot/switch assembly back slightly increasing the recess.

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cool, thanks! I’m looking forward to getting mine and putting it all together. It’s going to be a bedside/ camping/ evening walks light, so it should be just about perfect :slight_smile:

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thanks for the review, that’s a great price for an 18650 sized edc host. handy too as I’ve recently had a few requests. At this price I could build a few with cells and charger at a nice price that doesn’t scare people off.

I’d probably go op with a 6*7135 driver and nw/cw choice, although I have found most are taken with the nw option (I demo on cars/engineering situations, the lessened glare and better rendering of nw appeals).

mat, can you post back here with your impressions of the op set up please?

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sure, will do gords :slight_smile: I’ll be putting a NW XM-L2 T5 in it with a 2.1A Nanjg, hopefully programmed with the BLF-VLD or lupodrv firmware. My wife forced me to do it, after she appropriated my Romisen RC-G2/ Nichia 219 bedside light. The sacrifices I make…

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With OP reflector, 4x7135 driver and XM-L U2 1C LED:

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Thanks for the review. You should write review somewhere in the title. I almost didn’t check this thread out, but I read all the reviews.

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cheers neckdo, that sorts it for me.
:slight_smile:

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Nice review thanks for the information!

Kind of reminds me of the old TR-801

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What I like about this host is it can take protected cells whereas the X-Power brother does not. I used a 8*7135 and when it has active cooling during skiing it barely gets warm, but of course gets too hot to hold if indoors with no circulation. I think I have a bad ground from the driver to the pill as sometimes it just blinks and goes out like the circuit has been opened even when the battery is known good. Once I get that problem licked this will become one of my favourites for skiing and biking unless the M2 host I ordered to use with the same driver beats it out.

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<edit>deleted... wrong thread.

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TSellers - you might be having battery bounce, particularly if your intermittent problems happen while you’re skiing. Try raising the switch inside the tailcap like Keltex did to increase pressure on the spring. It’s a pretty common problem among mtbers using torches for night riding and a stiffer or longer spring usually fixes the problem.

I got my C20 yesterday, looks really nice. Threads are well machined and run smooth, o-rings are lubed as stock. I haven’t had time to pull it apart yet (busy building a milling attachment for my lathe), but I’ll get stuck into it when my programming clip arrives. The only downside I can see is that the pill material under the star is pretty thin. I might see if I can add some copper to the pill to help out with that - I just found a nice 2in copper pipe cutoff which should help :slight_smile:

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Thanks Matt,

I’ll give your suggestion a try. One of the things I noticed was the light powers on as soon as the tailcap makes contact. I also noticed my solder job for the ground looks iffy, I’ve tried 3 times, and even scored the edge of the pill with a dremel, but I’m just not getting a good weld there. That’s why my theory that the battery bounce is actually moving the driver inside the pill. When I check continuity it is always positive but that doesn’t mean it just hasn’t reseated itself when I unscrewed the cap.

So if I do get this problem solved, now I wondering about something else. I see that FT has a 4.35 charger SKU’d up now. If I were to use a 4.35v cell with the 8* driver do you think it would result in any brighter light, or does the driver regulate it so that it would not make any difference?

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it would (in theory) keep the light regulated for longer, not brighter

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Thanks janko, think I’m just looking for a reason to justify starting to use the 4.35v cells!

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no worries :slight_smile: Tracking down an intermittent electrical problem is a pain in the bum, that’s for sure. Another way to troubleshoot would be to smack the light when it’s on with the tail cap on and off (with a nail or something between B- and host), as you could have something not quite right in your switch too. One way of making a good -ve connection on the driver is to just solder a piece of bare wire between driver -ve and pill. That might help too.

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Thanks, co-incidentally I just finished soldering again. Also this time I didn’t like the look of the solder bridge on the star that tells it the mode, so I redid that as well thinking maybe the mode was getting confused with a bad solder. So I tried your suggestion and gave it a few smacks while it was on and all good, but in the past it fails after it’s been on for awhile so I can’t be sure yet. I sure hope it works this time because for the first time the emitter is perfectly centered which is nice.

Also since I posted earlier I did find a previous thread where they said this driver does not really benefit from a higher voltage feed, and it can be worse in fact, apparently at 6v for example it’s only 60% efficient with tons of heat as the result. So in fact I’m thinking maybe the best cell for this light would be an a123 18650 LiFePO4 cell and not a Li-Ion.

Update: the intermittent problem was due to bad ground between driver and pill. Seems OK now.