I am still quite new to 18650s, so I hope some "expert" might better enlighten me on safe charging practices for lithium cells
What I am now doing is:
1. I've gotten this rather big 11 gallon steel bin from IKEA.
2. In this bin I put my charging setup, a Xtar SP2. A small copper shim with a K-type thermocouple bead soldered onto it is placed across the bodies of the cells during charging, and the shim is held in place using a small elastic band
3. The thermocouple is then hooked up to a Extech 421509 data acquisition device with alarms set to go off when the shim reaches 40 degrees.
So far, it seems to be working fairly decently. If both cells get warm during charging, I catch it fairly early when they are both around 40 degrees each. If only a single cell warms up during charging, the buzzer will still go off, albeit somewhat later when the cells are close to 60 degrees. But either way, I do get some audible alerts warning me of hot cells.
My big concern though is: is temperature the only thing that I ought to be monitoring? Is it possible for a cell to "vent with flames" when it is completely cool to the touch at 35 degrees?
See Rule #3 Do not Hot Link images. Please host on an image site, Imageshack or similar and repost – Thanks Norm
never heard it happen,
shorted cells blow up, but they get hot before.
reverse charge cells blow up, but it only happens in multicell set up, under load, not in charger (unless you insert the cell backwards and charger has no reverse polarity protection.
so i wouldn't worry especially in 11 gallon steel bin