Search found 317 matches

by docware
Jan 22 2020 7:50am
Forum: Battery Technology
Topic: Li-ion cells cycle ageing
Replies: 472
Views: 48854

Re: Li-ion cells cycle ageing

From 4.05 to 4.2V termination point is I understand not significant actual usable mAh capacity, just "surface charge". Maybe even 4.00? No, no, there is a LOT capacity between 4,0 and 4,1 V. I mean resting voltage. It´s obvious from SOC chart as well from discharge graphs. So optimal charging volta...
by docware
Jan 22 2020 12:53am
Forum: Battery Technology
Topic: Li-ion cells cycle ageing
Replies: 472
Views: 48854

Re: Li-ion cells cycle ageing

madin88 wrote:
Jan 21 2020 2:05pm

What about doing another test with M36 or MJ1 between 4,2 and 3V? I would like to see what happens then with cycle life.
Knowing that MJ1 and M36 were doing well at Pajda´s 100 % DOD 1C disch. testing, we can be sure that 4,2 – 3 V cycling would be also OK.
by docware
Jan 20 2020 4:33pm
Forum: Battery Technology
Topic: Li-ion cells cycle ageing
Replies: 472
Views: 48854

Re: Li-ion cells cycle ageing

Just now I have energy density data only for M36 and 50E.

LG M36 .................... 250 Wh/kg, 694 Wh/l at 1 A discharge
Samsung 21700 50E ..... 258 Wh/kg, 722 Wh/l at 1,5 A discharge
by docware
Jan 20 2020 3:17pm
Forum: Battery Technology
Topic: Li-ion cells cycle ageing
Replies: 472
Views: 48854

Re: Li-ion cells cycle ageing

Well, I´ll try to explain. Let´s say I want to build new battery 48 V. I am limited by size and weight because nobody want to have big and heavy battery on the bike. So that maximum acceptable solution is let´s say 13s6p of 18650 cells. Or 13s4p of 21700 cells. Now it´s up to me what cells I decide ...
by docware
Jan 20 2020 2:16pm
Forum: Battery Technology
Topic: Li-ion cells cycle ageing
Replies: 472
Views: 48854

Re: Li-ion cells cycle ageing

are the cycling C-rates and LVC supposed to be "relatively standardized", and how so? otherwise longevities wouldn't be comparable, right? Volume proportion of 21700 to 18650 is 1,46 x. We can build 20 Ah battery with 4p high capacity 21700 cells or 6p high capacity 18650 cells. That is 1,5 ratio. ...
by docware
Jan 20 2020 11:31am
Forum: Battery Technology
Topic: Li-ion cells cycle ageing
Replies: 472
Views: 48854

Re: Li-ion cells cycle ageing

New pair of cells started cycling test, SONY VTC6 and Samsung 21700 50E. SONY VTC 6 is running with parameters charge 1A / 0,1 cut off to 4,1 V, discharge 2,5 A to 3,3 V. SONY VTC6 was chosen because it is an interesting cell in the high power category, moreover until now there wasn´t any SONY repre...
by docware
Jan 18 2020 3:11pm
Forum: Battery Technology
Topic: Li-ion cells cycle ageing
Replies: 472
Views: 48854

Re: Li-ion cells cycle ageing

Excellent work docware! But as you know me :wink: , I have again one remark to the cell surface temperature profile graph. I think it would be helpful, particularly for newbies interested in this topic to add a legend (some graphical delimiter) where is in the graph located: charge / rest time / di...
by docware
Jan 18 2020 6:22am
Forum: Battery Technology
Topic: Li-ion cells cycle ageing
Replies: 472
Views: 48854

Re: Li-ion cells cycle ageing

New data for new year 2020. All cells were resting at 3,5 V / 15 °C for 2 weeks during Christmas because the table was occupied by Christmas tree. Thanks to this pause we can see some partly capacity recovery of 29E7 and GA. Capacity degradation would be probably slower in real life for these two ce...
by docware
Jan 09 2020 7:21am
Forum: Battery Technology
Topic: Best 18650 cell for 3p 18A max
Replies: 23
Views: 1084

Re: Best 18650 cell for 3p 18A max

Maybe LG HG2L can be alternative .....

viewtopic.php?f=14&t=103161&p=1508960#p1508960
by docware
Jan 09 2020 6:00am
Forum: Battery Technology
Topic: Best 18650 cell for 3p 18A max
Replies: 23
Views: 1084

Re: Best 18650 cell for 3p 18A max

Yes, LG HG2 may be the proper cell, but be aware of the many fake HG2 cells. Advantage of such small battery pack is lower weight and size, disadvantage rather shorter lifetime.

viewtopic.php?f=14&t=101779&p=1488141#p1488141


LG MJ1 DCIR.jpg
LG MJ1 DCIR.jpg (172.67 KiB) Viewed 772 times
LG HG2 DCIR.jpg
LG HG2 DCIR.jpg (170.92 KiB) Viewed 772 times
by docware
Jan 06 2020 4:20pm
Forum: Battery Technology
Topic: Li-ion cells cycle ageing
Replies: 472
Views: 48854

Re: Li-ion cells cycle ageing

I believe Pajda´s explanation is sufficient. Bellow is 29E7 No5 full capacity measured before cycling test. Initial 2 200 mAh at the start of cycling is 78,8 % of full capacity. As the latest long life cell from Jeff Dahn´s team will not be available to us early, M36 seems to be really good choice f...
by docware
Dec 25 2019 3:45am
Forum: Battery Technology
Topic: Li-ion cells cycle ageing
Replies: 472
Views: 48854

Re: Li-ion cells cycle ageing

Shunt wrote:
Dec 25 2019 12:58am
M36 - I can't wait to see how they do at 2C . Is there any chance one of you guys could run 100 cycles at 5 or 6 amps before I get my equipment ? Just so I know if it's even worthwhile to start them at that rate?
No, there isn´t. By the way, MJ1 is probably better choice than M36 for such load.
by docware
Dec 24 2019 6:23pm
Forum: Battery Technology
Topic: Li-ion cells cycle ageing
Replies: 472
Views: 48854

Re: Li-ion cells cycle ageing

Docware, When you decide to finish cycle testing, could you please make a full cycle test as per datasheet (for me at least on the PF )? Would be good to see if full capacity will have the same degradation than the voltage limited one... Thank you for all your efforts doing these tests! T. Yes, tha...
by docware
Dec 24 2019 2:10am
Forum: Battery Technology
Topic: At rest voltage and status of charge ???
Replies: 27
Views: 1538

Re: At rest voltage and status of charge ???

Docware, that sure looks like voltages at rest, so that chart is just what I'm looking for. Now the big question...Since top of charge voltage at rest definitely changes with age, how does the rest of SOC voltages change with age, especially that 50% point? Currently have no data, but want to colle...
by docware
Dec 23 2019 4:06pm
Forum: Battery Technology
Topic: At rest voltage and status of charge ???
Replies: 27
Views: 1538

Re: At rest voltage and status of charge ???

Docware, that sure looks like voltages at rest, so that chart is just what I'm looking for. Now the big question...Since top of charge voltage at rest definitely changes with age, how does the rest of SOC voltages change with age, especially that 50% point? Currently have no data, but want to colle...
by docware
Dec 22 2019 5:00pm
Forum: Battery Technology
Topic: At rest voltage and status of charge ???
Replies: 27
Views: 1538

Re: At rest voltage and status of charge ???

Do you mean something like this table ?
SOC% versus voltage 17.12.2019.jpg
SOC% versus voltage 17.12.2019.jpg (364.53 KiB) Viewed 1002 times
by docware
Dec 22 2019 4:15pm
Forum: Battery Technology
Topic: Li-ion cells cycle ageing
Replies: 472
Views: 48854

Re: Li-ion cells cycle ageing

The 1A rate is fine, but to be more fair, what about using 0.5C for comparability across a wide range of cell capacity sizes? so larger cells aren't artificially rewarded and smaller capacity models aren't penalized I´ve been trying to choose such testing parameters that are close to real ebike con...
by docware
Dec 22 2019 4:34am
Forum: Battery Technology
Topic: Li-ion cells cycle ageing
Replies: 472
Views: 48854

Re: Li-ion cells cycle ageing

Christmas package special delivery :) . PF and GA 600 cycles, M36 550 cycles, 29E7 480 cycles, 30Q 189 cycles, MJ1 150 cycles. Comparative charts on capacity and DCIR added. Panasonic PF 600 cycles.jpg LG M36 550 cycles.jpg Sanyo GA 600 cycles.jpg Samsung 29E7 480 cycles.jpg Samsung 30Q 189 cycles.j...
by docware
Dec 16 2019 8:17am
Forum: Battery Technology
Topic: My setup for battery research / development
Replies: 21
Views: 1577

Re: My setup for battery research / development

- Now add a second sh*t used cell to this 2P block, will be a final 3P block . One new and two crappy old cells mixed parallel. Do test discharge from 4,2V to 3,0V @ 1A for this 3parallel cells and write results. -Get amazed with results Sayy woww batteryGOLD, if you look at any discharge chart, yo...
by docware
Dec 12 2019 3:15am
Forum: Battery Technology
Topic: Li-ion cells cycle ageing
Replies: 472
Views: 48854

Re: Li-ion cells cycle ageing

Yes, M36 looks very nice, 29E is also good, especially DCIR. PF not so, on the other hand PF can serve lot of years for many people. This test confirms good 29E lifetime flippy always insisted, speak nothing of excelent LG M36 pajda each time highlighted. It takes about 11 weeks to do 500 cycles. My...
by docware
Dec 10 2019 1:47pm
Forum: Battery Technology
Topic: Li-ion cells cycle ageing
Replies: 472
Views: 48854

Re: Li-ion cells cycle ageing

New batch : PF and GA 500 cycles, M36 475 cyles, 29E7 400 cycles, 30Q 111 cycles, MJ1 82 cycles.
Panasonic PF 500 cycles.jpg
Panasonic PF 500 cycles.jpg (179.52 KiB) Viewed 2831 times
LG M36   475 cycles.jpg
LG M36 475 cycles.jpg (179.86 KiB) Viewed 2831 times
Sanyo GA 500 cycles.jpg
Sanyo GA 500 cycles.jpg (183.93 KiB) Viewed 2831 times
Samsung 29E7  400 cycles.jpg
Samsung 29E7 400 cycles.jpg (180.52 KiB) Viewed 2831 times
Samsung 30Q  111 cycles.jpg
Samsung 30Q 111 cycles.jpg (167.35 KiB) Viewed 2831 times
LG MJ1 82 cycles.jpg
LG MJ1 82 cycles.jpg (165.83 KiB) Viewed 2831 times
by docware
Dec 01 2019 3:14pm
Forum: Battery Technology
Topic: Li-ion cells cycle ageing
Replies: 472
Views: 48854

Re: Li-ion cells cycle ageing

Docware, What is your DCIR measurement methodology? I want to check my 4 years old battery for comparison. Thx, T. I measure DCIR according INTERNATIONAL STANDARD IEC 61960-3:2017, paragraph 7.7.3 "Measurement of the internal DC resistance". Full name of this standard : Secondary cells and batterie...
by docware
Dec 01 2019 7:34am
Forum: Battery Technology
Topic: DIY High Cell Count Balance Charger for Cheap
Replies: 27
Views: 3024

Re: DIY High Cell Count Balance Charger for Cheap

I find it hard to believe that your cells are within 1.5% after repeated use and charging cycles. It´s no problem to have cells within 0,1 % (3 - 4 mV) after 2 years running the pack without any balancing. But those are gently utilized true original Sanyo 18650 cells, not heavily used Lipo. Battery...
by docware
Nov 29 2019 8:41am
Forum: Battery Technology
Topic: Li-ion cells cycle ageing
Replies: 472
Views: 48854

Re: Li-ion cells cycle ageing

Re: Optimal Charge Voltage - (LiCo) Quote by liveforphysics » Dec 02 2014 3:16pm „ While I agree NCA is the cat's pajamas, you are attributing too much to the cathode material chemistry. The cathode chemistry itself is neat, and everyone loves to talk about it, but as far as making a cell safe or du...
by docware
Nov 28 2019 7:26am
Forum: Battery Technology
Topic: Li-ion cells cycle ageing
Replies: 472
Views: 48854

Re: Li-ion cells cycle ageing

Let me refresh the pages with help of few images. PF, M36 and GA after 400 cycles. 29E later.
Panasonic PF 400 cycles.jpg
Panasonic PF 400 cycles.jpg (170.31 KiB) Viewed 3396 times
LG M36 400 cycles.jpg
LG M36 400 cycles.jpg (167.11 KiB) Viewed 3396 times
Sanyo GA 400 cycles.jpg
Sanyo GA 400 cycles.jpg (171.33 KiB) Viewed 3396 times