That tmart pack is Parallel.
Thanks halo. Is there anything in particular I’m looking for in those strips?
I didn’t see that. Ew.
Bigger is better… … … copper is better… etc etc. I assume you want this for pretty low current uses?
Building a parallel 2x18650 stick with protection sounds like a doozy:
- Needs an insulation disk between the two cells.
- Case negatives need to be joined, so there’s a strip to strap those together. This is a “power” connection.
- Positive poles must be joined, strip for that. Another power connection.
- Positive connection for protection circuit, strip for that. (Signal connection, does not need to be heavy duty.)
Typically all of those connections would be spot welded.
What light would this be for?
except it won’t fit.
I wasn’t planning on using a protection circuit or unwrapping a cell. Positive to positive, negative to negative, and shrink wrap it up.
Richard
Maybe you can put a memo on Mountain’s Nitecore Digicharger D4 webpage letting people know that if they want to charge 26650 cells, they better look at a different charger. They are too wide to fit in the D4 and I had to rubber band my 26650 cells down in the outer banks so they could stay in place long enough to charge.
Seriously? Thanks for the heads up. I know that I had charged 26650s in my i4 for a while (SLOW), and while they were awkward to get to connect they did work. I'll take a look at the charger and make a note.
The Xtar VP4 would work. It’s outer banks are nice and wide. Plus it’s got the rebate that I didn’t notice when I bought my D4 and EVVA 26650’s. DOH! 
If it really isn't working for you, send me a PM and we can work something out.
So i might have to order some more parts. Like an idiot i fried something trying to solder to an aluminum pill. Is it more likely that the LED fried or the driver or both?
It’s ok. I just wanted people to know before they got the D4 that if they wanted to use it to charge 26650’s that they better look at something like a Xtar. As for 18650’s, it charges those like nobody’s business and is a awesome charger for that.
I would suspect the driver, especially if that's what you were trying to solder, but it's easy to test the LED. Something on the driver may have just shifted when the solder melted on the board so you still might be able to save it.
I thought i didn’t have another emitter to test it, but i salvaged one from a dead solarforce p60 and it turns out the driver is fine, i fried a nice dedomed XPL. On the plus side, I guess it’s a testament to the heat moving abilities of a noctigon and good thermal paste
I have a few Nitecore chargers. The D4 charges the 26650 batteries in the inside slots. You can only fit 2 at a time..not 4
You can’t solder to aluminum. If there is no driver retaining ring you can buy them on fasttech or just wedge a ground wire between the pill and driver.
Yeah I’m smarter than that. I was getting really frustrated with it and finally gave up. Then when I was laying in bed, I thought to myself “You idiot, that pill is aluminum.” I just wasn’t thinking at the time
Richard,
Do you have an ETA on more uf-t20 and xintd c8 xpg2 flashlights? I want both, and prefer ordering from you.
I also wanted to let you know I love the red p60 dropin you put together for me.
Got my latest order Richard, thanks! 
Hopefully soon on the UF-T20. I put in the order several weeks ago, but I haven't received tracking information yet. That said, I did receive a notice from UPS that a large package is coming tomorrow that I didn't know was coming, so that might be them.
I just got shipment notice on the XinTDs, so they should be here by next week or this weekend.
Glad you like the dropin!
However, the D2 works smashingly for 26650 cells (if you don’t mind the relatively slow charging speed). And I’ve heard that the D4 works but may only be able to fit one cell at a time (inner slot) unless you add some sort of adapter (for an outer slot).
I’m pretty happy with my D2. It can charge nearly any Li-Ion/LiFePO4/NiMH battery, it uses good charge algorithms, it displays realtime progress details, both bays are totally independent, and my particular unit stops at 4.18V (I prefer a slightly less-than-maximum charge, to prolong cell life). It has replaced my old Nitecore i4 charger, which lacked the nice display and LiFePO4 support and low-current option and overcharged to 4.24V.