I have a friend how has accumulated some old laptop 18650’s.
He has asked to me to recommend a 2x18650 light to use them in.
I know that previously the FandyFire STL-V2 and the TrustFire X8 were good suggestions.
Is this still the case or is there anything newer out there under $50?
Thanks.
In my opinion I would not recommend putting unprotected old laptop batteries in series. But I am sometimes too cautious.
I only run unprotected cells in my 2x18650 lights. I must say though that they really do not get used much and I top up the cells every few months.
My Suggestion:
I bought one of these, and it is a nice torch: (takes 18650s with provided adapters, as well as 26650s)
http://www.ebay.com/itm/200899600521?ssPageName=STRK:MEWAX:IT&\_trksid=p3984.m1438.l2649
Or the X8, a Steal”
Or This, Which I own from this Seller, and it is a Quality Light:
http://www.ebay.com/itm/140896173852?ssPageName=STRK:MEWAX:IT&\_trksid=p3984.m1438.l2649
Also, very Bright and Cheap 3T6:
http://www.ebay.com/itm/300669256637?ssPageName=STRK:MEWAX:IT&\_trksid=p3984.m1423.l2649
How about something that uses 2 18650’s in paralell? Much safer than series.
That’s where the +Small Sun ZY-T08 +shines. 
“The King:”
T-07
T-08
Remember, the tops of the Batteries in any Parallel light have to be Perfectly smooth to avoid scraping the Contact Board!
That looks awesome with no tail cap button.
...Another vote for the ZY-T08:
Parallel cells = safer, especially for used and unprotected laptop pulls.
I’ll just reiterate, using old laptop pulls in a series light strikes me as a terminally bad idea, are they a matched set? matched capacity and internal resistance? are they even from the same packs or are they all mixed up?
I’d really suggest using them in single cell lights, it strikes me he only wants a 2s light to use more cells up at once, why not suggest he gives a few single cell lights a try out? say an edc nanjg based tube light, an xintd c8, maybe since he seems handy, he might enjoy building a few lights for himself?
but using recycled unprotected pack pulls in a series configuration could really end badly.
+1
Many thanks for all of the replies.
+1
Please - no unprotected, 2nd hand cells in series.
You can get plenty of output from single cell lights and if runtime what he's looking for then go with parallel configuration as suggested by others.
Don't forget to use lights with a low-voltage cut-off so as not to over-discharge the cells.
I use laptop pulls in series, and it can be done safely if you know the dangers and follow the do’s and don’ts religiously. I don’t recommend using them in applications where you use the light for extended periods. And I don’t recommend using them at all unless you’re willing to be careful about how you treat them.
Does your friend have a DMM? Can he tell you the do’s and don’ts? Does he know how to match cells for capacity and internal resistance? Does he have a hobby charger to keep them balanced? If not, I don’t recommend using them in series.
I’ll have to agree with gords1001. I must bee a wimp or something, I even only use protected cells in singles, over careful maybe but less chance of a “pipe bomb” situation.
