battery temp while discharging

5 posts / 0 new
Last post
USSR
Offline
Last seen: 6 years 9 months ago
Joined: 07/12/2012 - 15:13
Posts: 74
Location: Pakistan
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 ? 

 

 

 

 

 

 

 

 

Edited by: USSR on 08/21/2015 - 07:25
snakebite
snakebite's picture
Offline
Last seen: 3 weeks 2 days ago
Joined: 11/20/2013 - 20:21
Posts: 2120
Location: dayton oh

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

TheBo
TheBo's picture
Offline
Last seen: 7 months 3 days ago
Joined: 01/07/2015 - 14:52
Posts: 612
Location: OBLIVION, ITALY
snakebite wrote:
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

Rufusbduck wrote:
Getting discouraged is normal but doesn't finish the job.
USSR
Offline
Last seen: 6 years 9 months ago
Joined: 07/12/2012 - 15:13
Posts: 74
Location: Pakistan

TheBo wrote:
snakebite wrote:
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 !{width:90%}http://i.imgur.com/mPQ1YUu.jpg![/quote]

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 

TheBo
TheBo's picture
Offline
Last seen: 7 months 3 days ago
Joined: 01/07/2015 - 14:52
Posts: 612
Location: OBLIVION, ITALY

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

Rufusbduck wrote:
Getting discouraged is normal but doesn't finish the job.