Originally Posted by
loimpact
I will search immediately hereafter but wonder if the flat tops are smaller in height than the button tops? The button tops were a @#$%% to get out last night. My older Fire cells (unprotected) were significantly shorter than the newere ones which were the full 69.5mm tall. I figure if eliminating the button top might help that, I'd certainly go for those.
Which leads me to wonder then...... Are there 4 versions of each cell??
Example:
NCR18650b "flat / unprotected"
NCR18650b "button / unprotected"
NCR18650b "flat / protected"
NCR18650b "button / protected"
I (if I were Panasonic) would've probably made a suffix designation to cover each of those variables so there would never be a guess or a possible "oops, we sent you the wrong NCR18650b" scenario. But maybe I'm thinking too hard.
If my memory is correct, I read from somewhere that the button top are an add on from the manufactory. Flat top were made for battery pack where they can spot weld connecting tab on the battery for the connection. The button most likely will add some dimension to the cell.
There is no different version of the NCR18650 cell when it comes to protected or non protected. Panasonic only makes the cell bare. They are unprotected. What happens after that is a different story. The seller of the battery can put in their own protected circuit board then place their own shrink wrap label. The bad thing about this is that the protection PCB can be a low quality board and the well know fact where the label is printed with a much higher rating than the actual real rating of the cell.
The unprotected older Fire cell you had will be shorter than most cell that are protected because the PCB will add couple of millimeter to the overall length of the battery. If you are interested in the length of the various cell out there, someone at Candle power forum had a good chart showing dimension along with many other info. I think his user name was HKJ.