Reddit mentions of uxcell 2 Pcs Black 18650 Flat Tip Batteries Battery Holder Case w Wire Leads

Two Panasonic NCR18650B 3.7V 3400mAh Rechargeable Li-ion Batteries QTY 2 https://www.amazon.com/dp/B00DHXY72O/ref=cm_sw_r_awd_3LGQub1ZPPSXH



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2 Pcs Black 18650 Flat Tip Batteries Battery Holder Case w Wire Leads https://www.amazon.com/dp/B00CQKBQBE/ref=cm_sw_r_awd_90GQub0CGQFKP

It all depends. The battery in these things aren't going to be rechargeable. I would simply remove them. What you want are the charging circuit and the hardware in the pack itself. Once you remove the internal battery you could wire your own and just use 18650 rechargable batteries which are very inexpensive.

In the end it would cost you no more than $20 for a pretty cool DIY project which would help you quite a bit while traveling. You can get a 6 pack of 18650 batteries for $19 and get six of the holders and solder them in series. The batteries are 3000mAh giving you a power bank of 18000mAh for about $40. 18k mAh commercial power packs usually go for ~$60. So you do a cool project and save a few bucks.

I'm assuming .5v drop as when I fire the device the battery volt indicator usually drops .4-.5v but I could just be reading it all wrong.

I am using 20g wires like the ones that come with it for load side stuff. Went with some solid core copper stuff I had as well as the wires that came with the chip, so I assumed it would be adequate. The only stuff I used other then that was some 24g but that was for the led button and the switches.

The varitube 510 didn't come with a negative solder point so I might need to check my solder joint as I had a heck of a time getting it to sick to the side of the brass nut.

Edit:

The battery holder is this but I cut off the original wires and soldered on some of the 20g stuff that came with the SX chip. Perhaps the spring and top contact just suck on this holder?