battery temp while discharging

hi

i extracted different 18650 from differnet battery cells . they hold 50-80 % of the capacity of actual cell using opus bt 3100v2.2

while discharging them at 0.7 A or 1 A their temp using infrared thermometer gm550 is 42-43 degress Celcius after 75 minutes of discharge (while discharging is still under way ).

Room temperature here is 34-35 Celcius

is it acceptable ? whats yours ?

those are tired.
high i r means heating under load and lower voltage.

yeah they are old or abused…they have high impedance, wich means lot of the current disperses into heat

these are discharge graphs of 3 batteries at 4Amp in my room in winter
Now we are in summer, but these are also 4A and discharging is much more warming than charging
To be honest if I charge them at 4A, the barely get warm, so it’s very strange that at 1A they even change significantly their temp

Your temperature starts at 17 mine room temp is 34-35. D C. So at 1amp discharge it's temp raises by 5 to 7 degrees.

These are not IMR type of batteries these are icr type extracted from dead or depleted laptop batteries

yeah i’ve considered it, don’t know exactly if the raising in temperature is linear or exponential considering the Room temperature. I mean maybe +7 deg starting from 20*C takes more energy than +7°C starting from 40°C
Also please note that NCR18650B is not an IMR an its std Chg rate is 1625mA
Btw we do not know the C of the batt, I think anyway that at worst you are at 0.7C

Anyway i think you could continue using them, but not in high discharge lights, just use them as “always charged” batteries for emergency situations