It is so funny to see this topic (18650 sanyo cells get's very hot) come up time after time.
Also the same answers time after time. Well some Sanyos are just "Heaters". Maybe we need a FAQ for that subject alone.
The reason Sanyoshave become known as heaters is that everyone just seems to throw these cells with a reasonable Voltage usually >2.8Vinto a charger at 1A and wonders why some get hot and some don't. Gee I had 2 cells both at 3V and one got blistering hot while the other one stayed nice and cool what's up with that???? is always asked. There really is a simple solution to this puzzle and yes you guessed it it is IR!!!!
( I probably should change my user title from Senior Memberto a custom one "IR King")
So I will give everyone a challenge that is interested:
If you purchase a 4 wire kelvin 1kH AC m? meter such as this.
YR1030
and use it properly to measure the IR of Sanyo cells with an initial Voltage of at least 2.5V andaccording to this IR guideline.
Then if you get more than 5 heaters (>35C with a 25C ambient temperature charging at 1A)in100(one hundred)cells (or more than 1 in 20) I will pay for the IR tester up to $60.00 US
That is how confident I am that this "Heater" issue can be put to rest once and for all with a simple ~50 dollar tool and a precharging IR check. Besides once you have the IR tester you will wonder how you ever survived without it.
Please be sure to record all your findings in a proper format to receive the prize money.
Any questions just ask.
Thesecells in the picture wereall withinmyIR limiting criteria and not a 1 was a heater. This is just a sample. My data for the IR criteria comes from 1348 Sanyo cells tested and recorded.
I am putting my money were my mouth is so anyone up for the challenge?
Wolf