40T cycle test

[goatman]

Ive been seeing some odd behavior in two other battery tests and i wanted to check to see if my tester is acting up. the 40T has given a steady result through out this test. i just want to see if the cell mah drops by 10mah/cycle after about 30hrs of cycling

battery has sat for 30 days and voltage was 4.139v, charged to 4.2v

the settings

the last cycle, #433 d-3021, c-2980

peak discharge temp is 102f

#434 d-3019, c-2943
#435 d-2993, c-2947
#436 d-2994, c-2950
#437 d-2994, c-2950
#438 d-2995, c-2950
#439 d-2995, c-2952
#440 d-2996, c-2952
#441 d-2996, c-2952
#442 d-2998, c-2953
#443 d-2995, c-2952
#444 d-2996, c-2954
#445 d-2997, c-2954
#446 d-2997, c-2955
#447 d-2998, c-2956
#448 d-2999, c-2956
#449 d-3000, c-2956
#450 d-2999, c-2956
#451 d-2998, c-2956
#452 d-2998, c-2954
#453 d-2997, c-2954
#454 d-2996, c-2954
#455 d-2995, c-2954
#456 d-2996, c-2954
#457 d-2996, c-2954
#458 d-2996, c-2954
#459 d-2996, charging to 3.6v and putting it on the shelf. sept.11/6pm

wanted to check my tester again because i might have some bunk 30q that im testing. oct.03

#460 d-2983, c-2939

 

[goatman]

left the battery in the freezer at -10 celsius for 2 days to compare with the P42a heres the link
https://endless-sphere.com/forums/viewtopic.php?f=14&t=107573&p=1597398#p1597148

volt sag

at 3.65v temp reached 75f

final temp at 3.2v was 95f

 

[goatman]

while testing the 30Q, i noticed the 0.6 amp capacity test brings mah back into the cell and the more i do it the discharge line seems to be smoothing out.

the 40T capacity test discharge line has the same "look" as the 30Q so im going to see if the same happens to the 40T

40T capacity line
https://endless-sphere.com/forums/viewtopic.php?f=14&t=106550#p1560561

30Q capacity line

#462 d-2993, c-2950
#463 d-2996, c-2950 doing 0.8amp discharge capacity test
d-3703, c-3554
#464 d-3169, c-3098
#465 d-3138, c-3089 doing 0.8amp discharge capacity test
d-3729, c-3560 seems to be the same as 30Q, ill keep repeating these short cycles
#466 d-3146, c-3098
#467 d-3138, c-3088
#468 d-3131, c-3080
#469 d-3122, c-3071
#470 d-3114, c-3063
#471 d-3104, c-3054
#472 d-3095, c-3046 doing 0.8amp discharge capacity test
d-3701, c-3540 going to continually cycle the capacity test with no wait time between charge/discharge 3x

d-3706, c-3544
d-3615, c-3539
d-3611, charged to 3.5v and put on shelf
looks like something you might do every 50 or 100 cycles

continuous capacity test

 

[pwd]

Not sure if you've seen this but there is a new revision of the 40T cell labeled as the 40T3. https://cdn.shopify.com/s/files/1/0481/9678/0183/files/Samsung_Introduction_of_New_40T_v3.pdf?v=1612843210
From one of the comparisons in; it seems it may be slight better under freezing temps as well as some other differences.

 

[goatman]

put battery on shelf 2 months ago at 3.5v, its still 3.5v

30Q doesnt really lose any cycle life when continuously discharge/charge/cycling
https://endless-sphere.com/forums/viewtopic.php?f=14&t=108547#p1592108

will do a few cycles at these settings til the capacity numbers stabilize then will remove wait times to compare mah/cycle loss



#473 d-3129, c-3079
#474 d-3124, c-3071
#475 d-3117, c-3063
#476 d-3108, c-3055
#477 d-3101, c-3046
#478 d-3091, c-3038
#479 d-3083, c-3029
#480 d-3074, c-3020
#481 d-3066, c-3011
#482 d-3057, c-3005
#483 d-3051, c-2996
#484 d-3043, c-2991
#485 d-3038, c-2985
#486 d-3034, c-2981
#487 d-3030, c-2977
test had stopped, charged and restarted
#488 d-3046, c-2963 giving a 24hr break to use tester on another battery
battery was 4.16v charged to 4.2v
#489 d-3034, c-2947
#490 d-3000, c-2945
#491 d-2996, c-2942
#492 d-2991, c-2939
#493 d-2986, c-2933
#494 d-2979, c-2927
#495 d-2968, c-2914
#496 d-2954, c-2901
#497 d-2944, c-2890
#498 d-2938, c-2884
#499 d-2928, c-2875 removing 3.75amp charge
had a bad connection over the last 11 cycles, see if the numbers improve (see pictures below)
#500 d-3000, c-2933
#501 d-2990, c-2935
#502 d-2990, c-2936
#503 d-2991, c-2936
#504 d-2990, c-2933 thats about where the capacity should be, switching to continuous discharge/charge/cycle
#505 d-2988, c-2931
#506 d-2986, c-2932
#507 d-2985, c-2929
#508 d-2982, c-2927
#509 d-2980, c-2925
#510 d-2980, c-2924
#511 d-2979, c-2923
#512 d-2977, c-2923
#513 d-2978, c-2924
#514 d-2977, c-2923
#515 d-2977, continuous operation doesnt seem to affect its life cycle
test done, put battery on shelf

you can see bad volt sag at 10amps



fixed connection

 

[willo]

Hey @goatman what's your test rig?

 

[goatman]

ebc-a20
https://www.amazon.ca/Lead-acid-Batteries-Capacity-Discharge-Software/dp/B08Y5C2NSS/ref=sr_1_1?dchild=1&keywords=ebc-a20&qid=1615309772&sr=8-1