The process is new to me; just wanted to share.
In the picture, 18650 cells from left to right:
- Newly re-wrapped
- Ready to wrap - (with insulator temporarily in place)
- Cell inserted into wrap
- Bare cell (Sony IMR)
Note the marks on the + button are light sanding marks from removing the tabs and solder used in the oem pack. The bare cells were pulled from a Dyson pack which were so heavily glued it became easier to remove the old shrink wrap (lowest voltage was 3.96v which charged to 4.2v). The cells are very easily grounded/shorted in their bare condition, so they were carefully stored until the replacement wrap arrived.
Sourced the shrink wrap (0.25mm flat, or both sides combined) sold by the meter from Fastech
Process:
- Cut wrap to 70 mm lengths ($0.06 each @14 lengths + small scrap from a meter) using a Fiskars cutting board my wife keeps for hobby use
- Placed battery so that top would insulate and not cover the + pole
- Used hair dryer/blower to start shrinking at the top where it folds over
- Pushed battery out of tube, added (salvaged) insulator, put back in tube
- Finished top of battery, moved to bottom, finished body last
- Easy to fix your own [or make fakes |( ]
- After wrapping I use a permanent marker to label the + and - ends, add the date, a unique code for the cell, the initial voltage before charging, and also transcribe info printed on the cell (material I used in not very translucent)
Summary:
Much easier to do than I expected. After I found that I didn’t need to hold or fix the insulators it was - literally - a breeze. Finished cells compress to a hair under 65 mm and are ~18.15 mm in diameter with the material used.
70 mm worked perfect for these Sony IMRs - the bare batteries have a slight indentation where the wrapper goes over the edge (almost like a shallow negative button). With some of my pulls the bottom is completely flush and the wrapper is flush with the bottom and it does not wrap over the edge onto the bottom like I did these.
I’ll only use these in single cell lights with springs, so the over-wrap on both ends should help prevent accidental grounding and not create a problem. Otherwise, they might need a magnet between cells.
EDIT: The material is very slick inside, at least before heat is applied. I had thought it might be sticky or gummy and hard to slip the batteries in and out . . . but not at all.