18650 Twist Together Battery Holder

I go back and forth between using PVC pipe and end caps and using this modular system to hold 18650 batteries in series for my projects. These and my PVC caps use a 3mm x 15mm screw with a spring (purchased from DIGI-KEY #BCAA-ND) at the end of the tubes. 

For a single battery use the End cap (PowerStickEndCap-Part001) with the male version of the single battery holder (PSSingleCap).

For 2 batteries, just use the male and female version of the single battery holders, (PSSingleCap with PSSinBatPosCap-Part).

For 3 batteries, use: PSSingleCap with PSDualBatFemaleTwist or PSSinBatPosCap-Part with PSDualBatMaleTwist.

For 4 batteries, use: PSDualBatFemaleTwist with PSDualBatMaleTwist.