I was looking at lithium ion batteries while there was discussion of replacement of Hugo 2 batteries. (The latest 3 pages pretty much in the H2 thread.) I came across care of Li-Ion batteries.
Just one quick google tells us that Li-Ion batteries should not run too hot. E.g. I just googled 'lithium ion batteries safety care and use'.
This was one result from the
NATIONAL FIRE PROTECTION ASSOCIATION.
https://www.nfpa.org/-/media/Files/...afety-tip-sheets/LithiumIonBatterySafety.ashx
From this page:
• Keep batteries at room temperature.
• Do not place batteries in direct sunlight or keep them in hot vehicle
Am not sure how hot we can call room temperature. There are people use Li-Ion batteries in hot countries. In the UK Room temperature is, "The average room temperature in a UK home during the winter season is roughly
18°C, while central heating thermostats are generally set to around
20°C".
(Since no-one has reported an exploding Chord battery I suppose it's possible to say Hugo 2 is OK. (However there are quite a few reports of expanding Li-Po Mojo batteries, which is different battery technology.) I know that getting the batteries hot will reduce their life-time though. Or at least, that's information available on the internet.
The temperatures that people are describing in this thread do seem too high. I also read about H2Go when charging gets hot.