#### goatman

##### 10 MW

40T

capacity test

cycle #1 results and settings

discharge #50

discharge 100

discharge 149

discharge 200

discharge 300

discharge 351

discharge 400

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- Thread starter goatman
- Start date

40T

capacity test

cycle #1 results and settings

discharge #50

discharge 100

discharge 149

discharge 200

discharge 300

discharge 351

discharge 400

original test before cycling

after 126 cycles

after 250 cycles

after 375 cycles

463 cycles 3703mah

heres 126 but a wider view to get a better look at where the capacity loss is occurring

wider 250

wider 375

saved

the change in fast charge settings seems to be working, when I first started cycling I was losing about 2.85mah/cycle, I continued to make slight changes and got to about losing 1.85mah/cycle. I didn't think the cell would last 300 cycles but with the new changes im losing 1 mah or less/cycle. I might make 750 cycles with 80% capacity now.

heres cycle 1 charge numbers 3156 mah , discharge #2 3191 mah

heres cycle 49 charge numbers 3153mah, discharge #50 3189 mah

heres cycle 54 charge numbers 3149mah, discharge #55 3185 mah

#100 discharge capacity was 3176 mah

made more changes this is discharge #149, 3184 mah, yes it increased

#200 charge 3091mah, discharge 3140mah

#300 charge 3017mah, discharge 3055mah

#351 charge 2994mah, discharge 3039mah

#400 charge 2971mah, discharge 3016mah

it also seems if I can keep the start of charge temperature around 80f/81f I can maintain capacity loss to a minimum but at 82f/83f I start losing.

heres the battery temps at different stages

start of charge 80f

when 2amp charge switches to 3.75amps is 78f

when 3.75ap charge switches to cut-off amps 83f

end of charge 75f and start of discharge 75f

10amp to 7.5amp switch 85f

7.5amp to 5amp switch 90f

5amp to 1.5amp switch 88f

end of discharge 82f

the battery is performing almost too good. im at 3173 mah after 104 discharges. it started at 3191mah. that's only an 18mah loss after 104 cycles or 0.17mah/cycle. im going to do the 0.8amp discharge from 4.2v to 2.5v tomorrow to compare with the original test I performed before cycling to see the capacity and compare.

heres a capacity test of a different 40T that I was playing with, at 7amp discharge from 4.2v to 3.0 volts the battery temperature would peak at 107f. I thought it was heat that was killing the capacity down around 3.4v to 3.2v but now I think it was the 5amp charge

im testing the battery inside a closed cardboard box with a towel ontop to keep battery temperatures up. I don't open it up.

the other morning I noticed the discharge mah numbers were getting higher??? so I checked the battery temperature on my dmm and all the temperatures had increased by 5f.

I opened the box and the battery had slid up against the side of the cardboard box, just touching the cardboard increased battery temperature to 95f peak and improved the capacity available numbers.

I guess a ghost had moved my box

against cardboard

I moved it back and temperatures dropped 5f and the capacity dropped again

ill do another 4.2v to 2.5v capacity test at cycle 250

I noticed on the charts once I switched the rest time in between charge and discharge from 1 minute to 5 minutes, the at rest voltage dropped from 4.2v to 4.194v at 70 seconds then at 90 seconds it dropped to 4.191v and at 4m50s to 4.190 and discharge starts again at 5 minute mark.

I'm getting a pack 20s 6p triangle pack. 120 cells just paid. Now the waiting game.

how many amps is your controller?999zip999 said:I'm getting a pack 20s 6p triangle pack. 120 cells just paid. Now the waiting game.

Ok 90amp BMS continuous and 180 amp peak.

I was looking at the mxus v3 4t to go with it but the hs3540 that im running seems about the same on grins simulator only lighter. haven't decided which one yet. I like the silence of a DD

I bought a molicel p42a 21700 to test when im done this at same settings.

that increased the battery temperatures and the battery seemed to like it. heres the temperatures.

start of discharge 80f/26c, 10/7switch 94f/34c, 7.5/5 switch 100f/38c, 5/1.5 switch 97f/36c, end of discharge 89f/32c, start of charge 86f/30c, 2/3.75 switch 82f/28c, 3.75/cut off amp 90f/32c, end of charge 80f

after 100 cycles 3176 mah

after 149 cycles 3184mah

im trying to get the battery to run as close to 10 amps as I can without getting it too hot, im just going to let it cycle for awhile at these settings, its been putting out a steady number.

edit to add pictures.

never saw these glitches in the discharge chart before, but this is #231 with new settings for 99f

*edit* im going to add some numbers from cycle #375 for comparison

3.9v, 1012mah cycle #375

3.8v, 1460mah

3.6v, 2324mah

#375-3.6v, 2299mah

3.5v, 2712mah

3.4v, 3043mah

3.3v, 3144mah

#375-3.3v, 3086mah

3.2v, 3220mah

#375-3.2v, 3166mah

discharge #2 was 3191mah, that's 95% after 290 cycles. you really cant go with the cycle numbers because its too easy to manipulate the capacity numbers with temperature and I have been, at cycle #149 I was using closer to the temperatures im using now and the capacity was 3184mah.

the 4.2vto2.5v capacity test will have to be the reference

im running the battery a little hotter where it peaks at 101/102f and only lose about 0.3mah/cycle right now

I changed to 3.7a charge no real change except the curve

tried 3.65

3.85 is a little faster

4.0, a little slower

4.25a is faster,

the charging mah was 5mah higher than the previous 5 cycles but the problem was the battery temperature at end of charge, it was 77f/78f and took 7 minutes for temp to reach 76f/75f. I need the battery cycle test to start at 75f/76f or else peak discharge temps get too high

3.82amps

#127

#323

I saw fully charged voltage had dropped to 3.184v, I put charge amps back to 3.75a from 3.82a

#330

when cycling, normally start of discharge voltage is 4.191v, ive increased the 10amp discharge time, im still within peak temperatures, to speed up cycle time and will play with lower charge amps to see if I can increase the 4.191v at Start of discharge.

tried 3.5a and 3.0a with no observable change to voltage or mah, tried 2.5amp charge and again, no change so put charge amps back to 3.75amps

#300 was 3055mah, discharge #351 was 3039mah. averaging a loss of 0.3mah/cycle

4.2v-2.5v capacity test is done after 375 cycles, 3818mah. 90% of initial 4216mah

the battery lost 160mah over the last 300 cycles.

going to put this test on hold after discharge #450 to test another cell

makes me think if you kept the charge to 2amps this cell would do 1000cycles. i had to change the 2a/3.75a switch to 3.62v because the cell still suffers loss where it was switching at 3.6v, that was 150/200? cycles ago and it needs to be moved again to 3.64v.

the other thing is temperature, max temp is about 102f and if you keep battery temp between 102f and 95f it gives its best consistent capacity.

im going to be testing a molicel p42a and mnke 26650 20amp 5000mah at the same settings.

battery has been sitting on the shelf for 30 days, voltage dropped by 0.07 volts, its last discharge was 3016mah. charged to 4.2v to start test

cycle #422 battery discharge starting voltage was 4.2v, #423 was 4.191v

#422 d-3040mah, c-2965mah

#423 d-3016mah, c-2975mah

#424 d-3021mah, c-2979mah

#425 d-3022mah, c-2981mah

#426 d-3024mah, c-2982mah

#427 d-3024mah, c-2982mah

#428 d-3023mah, c-2982mah

#429 d-3024mah, c-2983mah

#430 d-3021mah, c-2979mah- the box the battery is in was open and peak temp dropped. closed lid again

#431 d-3020mah, c-2979mah

#432 d-3021mah, c-2980mah

#433 d-3021mah, c-2980mah- aug7, 7pm done for now.

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