Any suggestions for this light?

Hey, first post
I was wondering if anyone knew how this torch would work out:
This drop-in from Fasttech
These batteries from ebay, a lens and tailcap from fasttech. The body will be an old torch that took 2 d batteries., and the new batteries will be housed in 2 aa batery holders.

UltraFire is very low quality, they hold a fraction of the stated capacity and are more likely to explode or vent.
AA holder will work for 14500 format.
2x14500 is ~2x3.7 V that’s below your drop ins nominal voltage, won’t work. You’ll need at least 3 cells in series.

Hey Patrick, welcome to BLF!

1) DO NOT buy those batteries. Complete junk and very unsafe!

2) the mag drop in would work with your proposed battery voltage *(2s Li-ipn for 8.4v) however you should only expect around 1000Lm out of it at max.

*3) be careful using 14500’s in a holder, you will need a parallel holder, your typical cheap AA -> D cell adapter will be 3s config making 12.6v each if used with Li-ion meaning 2 of those adapters, loaded with 14500’s, placed in series with eachother, would deliver 24v, it would be like 6s li-ion. For 14500 you’ll need to build a parallel holder, otherwise you will need to use NiMh cells in your 2d mag conversion for about 7.8v total (that’s 6s NiMH).

I assumed he was referring to one of those sleeves converting 1 AA in D cell; if it’s a 3AA carrier, you’re right (i comment because the previous post clearly thought the same I did, and the OP didn’t mention what kind of adapter)

My sugestion would be to forget about that drop-in and crapy batteries and get something like TrustFire TR-3T6, price of this light is in 25-30$ range so for about the same amount you planned to spend on parts you get working product ready to go. As mentioned by fellows above, forget about ultrafire batteries and buy something like samsung or sanyo.

Reiterating and correcting some things:

  • Nothing wrong with using a dropin like that.
  • Do not use Ultrafire batteries. Search BLF for battery recommendations such as Sanyo, Samsung, Sony, LG, Panasonic, etc.
  • Do not use the cheap charger you linked. Search BLF for recommendations such as Xtar, Opus, Nitecore, etc.
  • Typical 2*AA -> D battery adapters are fine, they are in parallel. CK is thinking of something else. If you plan to use a pair of those adapters in series you’ll have a 2s2p configuration which is fine for that dropin. FYI the correct 3AA parallel adapters are also available for a 2s3p configuration which is also fine (same total voltage).
  • 14500 cells aren’t really that high capacity from any brand, why not go with Sirius9’s suggestion and get a whole new light? Then you can use 18650 or 26650 cells, have better heatsinking for the LEDs and a higher total output and runtime.

For your research on batteries and chargers I highly recommend digging in to HKJ’s website. Nobody here on BLF will recommend against that. http://lygte-info.dk - this website covers many chargers and batteries.

EDIT: OOPS! Looks like that’s a 9-22v dropin, that’s not going to work with your proposed configuration. They probably have a buck driver with the emitters in series. 8.4v just isn’t going to make anything happen. Time to rethink your plan.

good catch, I didnt realize those 2x adapter’s existed, didnt know there was a need with the 3s and 3p options. I suppose there’s a 2s as well, that could actually be somewhat useful to me (if it’s a more sturdy overall design)

If there’s a 2s adapter it’s not very common. (I mean that I don’t think I’ve seen one.) OTOH 4s1p AA trays are common. I figure endcaps could be easily made for those?

http://www.skycraftsurplus.com/batteryholderlong.aspx

http://www.ebay.com/itm/bOSS-DR-55-battery-holder-4AA-long-6v-/390696765738

For straight up 2s1p AA in the 1xD format I’d stick with the 3s adapters you were originally thinking of and just mod them to 2s.

I think I will go with Sirius9’s suggestion, to avoid losing money. Thanks for all the help, everyone! :slight_smile:

Good call!