18650 is a size declaration. HOWEVER, Not all 18650s are 650mm x 18mm. some may be 17600 or even 19700. Make sure the SPECIFICATIONS of the batteries you choose match what the DT battery clip says it can fit.
Unprotected cells may fit better but you MUST BE CAREFUL when putting them in as polarity is EXTREMLY IMPORTANT and reversing this may cause detriment to the battery, the device or both.
Any cells with a damaged wrapper must be re-wrapped. PERIOD!
NEVER ever store, charge or use these types of cells without a wrapper.
UNWRAPPED BATTERIES ARE EXTEREMLY DANGEROUS!!!
(even I have fumbled a batt i was wrapping on to a metal surface, once… the battery absolutely shorted out and created a spark near the top of the positive end. the whole body is a negative terminal. that lip at the top is the positive. it does not take much to short these out! oh and that ring at the top? DO NOT LOOSE THAT or you’ll have to buy a whole sheet of em. That ring is just as important as the whole wrapper for safety)
This video below uses a magnet to create a continuous short. do not do this ever!
watch this to learn how to re-wrap your batts.
Here are my rewrapped cells:
I invite the community to further discuss this topic here.
did i miss something? got a question? let us start discourse, here.