Search found 317 matches

by docware
Apr 02 2020 3:39am
Forum: Battery Technology
Topic: Li-ion cells cycle ageing
Replies: 472
Views: 49838

Re: Li-ion cells cycle ageing

New data : LG MJ1 700 cycles, SONY VTC6 482 cycles, Samsung 50E 407 cycles, Samsung 35E 400 cycles, LG HG2 362 cycles. LG MJ1 700 cycles.jpg SONY VTC6 482 cycles.jpg Samsung 50E 407 cycles.jpg Samsung 35E 400 cycles.jpg LG HG2 362 cycles.jpg Capacity decay comparison zoom offset 2.4.2020.jpg DCIR co...
by docware
Mar 22 2020 3:05pm
Forum: Battery Technology
Topic: Li-ion cells cycle ageing
Replies: 472
Views: 49838

Re: Li-ion cells cycle ageing

From the chart it looks like 35E could be the new GA in terms of capacity decay. I also wonder how a 18650 cell of LifePO4 would come out in tests like these. It might reveal something we never thought of, or just imagined how it should behave by myth. Frankly, I expected 35E to be worse than GA, b...
by docware
Mar 15 2020 4:56am
Forum: Battery Technology
Topic: Li-ion cells cycle ageing
Replies: 472
Views: 49838

Re: Li-ion cells cycle ageing

what is your indication why the 30Q suck so much? spec sheet wise it should behave better. If we read 30Q specification, it´s obvious that this cell was designed to provide high power output. Low internal resistance and high charge and mainly discharge currents is characteristic for high power cell...
by docware
Mar 13 2020 8:31am
Forum: Battery Technology
Topic: Li-ion cells cycle ageing
Replies: 472
Views: 49838

Re: Li-ion cells cycle ageing

flippy wrote:
Mar 13 2020 5:12am
what is your indication why the 30Q suck so much?
spec sheet wise it should behave better.
I have only this official 30Q specification. Do you have any other spec promising better lifetime ?
Samsung 30Q specification.jpg
Samsung 30Q specification.jpg (108.68 KiB) Viewed 1276 times
by docware
Mar 13 2020 4:09am
Forum: Battery Technology
Topic: Li-ion cells cycle ageing
Replies: 472
Views: 49838

Re: Li-ion cells cycle ageing

As John & Honk have said this really is fantastic testing by Docware, so kudos for the time consuming work being put in and aired here for all to view the results :bigthumb:. Yes, DCIR mapping is quite time consuming. Curiosity was driving force here, as usually. I just, as others, share informatio...
by docware
Mar 08 2020 7:40am
Forum: Battery Technology
Topic: Li-ion cells cycle ageing
Replies: 472
Views: 49838

Re: Li-ion cells cycle ageing

I was curious about DCIR after 700 cycles through the whole SOC range. Initial DCIR measurement (green line) and after 700 cycles (yellow line) was done on different cells. Conclusions: - Panasonic PF DCIR is really very different from others cells - the general shape of DCIR through SOC is confirme...
by docware
Mar 05 2020 3:56pm
Forum: Battery Technology
Topic: Li-ion cells cycle ageing
Replies: 472
Views: 49838

Re: Li-ion cells cycle ageing

Pajda wrote:
Mar 05 2020 3:44pm

..... Yes I measured similar trend with my 50E samples. My closest settings is 4.1-3.2V at 0.5C-1C rate. The 50E cycle life is outstanding. Slightly better are only M36 and M29. .........
Thank you Pajda.
by docware
Mar 05 2020 3:51pm
Forum: Battery Technology
Topic: Li-ion cells cycle ageing
Replies: 472
Views: 49838

Re: Li-ion cells cycle ageing

if im weed infesting let me know and ill stop after this post. I accept your suggestion, especially after reading your thread „ 100% discharge rate capacity “ , so thank you for no more posting here. https://endless-sphere.com/forums/viewtopic.php?f=14&t=104568 Just few citates from ES members to y...
by docware
Mar 05 2020 11:21am
Forum: Battery Technology
Topic: Li-ion cells cycle ageing
Replies: 472
Views: 49838

Re: Li-ion cells cycle ageing

New batch of data : Samsung 30Q 585 cycles, LG MJ1 550 cycles, SONY VTC6 312 cycles, Samsung 50E 258 cycles, Samsung 35E 227 cycles, LG HG2 181 cycles. Samsung 30Q 585 cycles.jpg LG MJ1 550 cycles.jpg SONY VTC6 312 cycles.jpg Samsung 50E 258 cycles.jpg Samsung 35E 227 cycles.jpg LG HG2 181 cycles.jp...
by docware
Feb 28 2020 1:51am
Forum: Battery Technology
Topic: Li-ion cells cycle ageing
Replies: 472
Views: 49838

Re: Li-ion cells cycle ageing

Here is Samsung 30Q No 3 condition before the cycling :

viewtopic.php?f=14&t=103092&p=1513064#p1513064

Cycle No 1 had 2180 mAh, average at cycle 535 is 1880 mAh.
by docware
Feb 27 2020 5:01am
Forum: Battery Technology
Topic: Li-ion cells cycle ageing
Replies: 472
Views: 49838

Re: Li-ion cells cycle ageing

DCIR of cycled cells is measured at approx 3,75 V, which is around 55 % SOC for most cells. Original intention was 50 % SOC, but I missed data I have now.
SOC% versus voltage  14.1.2020.jpg
SOC% versus voltage 14.1.2020.jpg (390.79 KiB) Viewed 1954 times
by docware
Feb 27 2020 4:30am
Forum: Battery Technology
Topic: Li-ion cells cycle ageing
Replies: 472
Views: 49838

Re: Li-ion cells cycle ageing

New data : Samsung 30Q 536 cycles, LG MJ1 500 cycles, SONY VTC6 267 cycles, Samsung 50E 216 cycles, Samsung 35E 182 cycles, LG HG2 127 cycles. Wrong DCIR data LG HG2 at 50 cycles corrected (originally wrongly measured with filter on). Samsung 30Q 536 cycles.jpg LG MJ1 500 cycles.jpg SONY VTC6 267 cy...
by docware
Feb 24 2020 1:04pm
Forum: Battery Technology
Topic: Li-ion cells cycle ageing
Replies: 472
Views: 49838

Re: Li-ion cells cycle ageing

Realistically, doesn't that "If" become more of a challenge the more P-groups (e.g. 10S4P vs 14S8P) even with top brand name grade A cells as the battery ages. I again ask administrators to ban this trolling member acces to this thread. eMark is responsible for weed infestation also in other thread...
by docware
Feb 24 2020 9:15am
Forum: Battery Technology
Topic: Li-ion cells cycle ageing
Replies: 472
Views: 49838

Re: Li-ion cells cycle ageing

It is simple. If my paralel groups are within 3 mV, resolution 0,1 mV is must for reliable and repeatable measurement. Requirement of ten times better resolution than measured values is valid not only for measurement of electrical values, but for measurement of all physical units generally. Good new...
by docware
Feb 23 2020 12:04pm
Forum: Battery Technology
Topic: Li-ion cells cycle ageing
Replies: 472
Views: 49838

Re: Li-ion cells cycle ageing

If so can the voltmeter be manually calibrated if you see it's drifted? No, volmeter can´t be calibrated. In fact, there is no reason as this simple-purpose instrument was built for comparative measuring of the parallel groups. So that absolutely accuracy was not the primary. However, thanks to bui...
by docware
Feb 23 2020 10:52am
Forum: Battery Technology
Topic: Li-ion cells cycle ageing
Replies: 472
Views: 49838

Re: Li-ion cells cycle ageing

Tend to agree, but when it comes to the iDST BattGo 8S it's more than a monitor and more reliable (+/- 2mV) than a cheap cell monitor. Citation from iSTD BG-8S manual : „Voltage measurement accuracy : ± 0,005 V @ 4,2 V“ You have to also take into consideration that iSTD unit is supplied from some m...
by docware
Feb 23 2020 10:21am
Forum: Battery Technology
Topic: Li-ion cells cycle ageing
Replies: 472
Views: 49838

Re: Li-ion cells cycle ageing

Thanks a lot! I guess you just meant the measurement / display component? Is there a build thread? https://m.aliexpress.com/storesearch/list/4-wires-variable-precision-voltmeter.html?sellerAdminSeq=202659690&searchType=storeSearch&storeId=923042&sceneId=050000&keywords=4-wires-variable-precision-vo...
by docware
Feb 23 2020 10:00am
Forum: Battery Technology
Topic: Li-ion cells cycle ageing
Replies: 472
Views: 49838

Re: Li-ion cells cycle ageing

My understanding of all inexpensive Chinese BMSs is that they only balance when cell disparity is more than 30mV I would not bother balancing a pack with a delta that small. Frankly, I consider delta above 5 mV to be out of normal. However, after slow battery charging nearly always all 10 groups ar...
by docware
Feb 23 2020 8:48am
Forum: Battery Technology
Topic: Li-ion cells cycle ageing
Replies: 472
Views: 49838

Re: Li-ion cells cycle ageing

I want to emphasize that I don´t recommend building battery pack without BMS. I appreciate that BMS can help charger and control unit safety functions like HVC, LVC, overcharge and overdischarge protection. I am only saying that balancing function of BMS is debatable and controversial. And those, wh...
by docware
Feb 23 2020 4:24am
Forum: Battery Technology
Topic: Li-ion cells cycle ageing
Replies: 472
Views: 49838

Re: Li-ion cells cycle ageing

https://rdtech.aliexpress.com/store/923042

Direct link doesn´t work. Go Products – DC Digital – DC voltmeter 5 Digit. Choose 4 wires variable precision voltmeter.
Need to have isolated battery power supply cca 8 – 12 V. Don´t recommend blue and yellow color, very unpleasant for eyes.
by docware
Feb 20 2020 10:58am
Forum: Battery Technology
Topic: Li-ion cells cycle ageing
Replies: 472
Views: 49838

Re: Li-ion cells cycle ageing

I use cheap 2 - 3 USD voltmeter on ebike for battery voltage/SOC. For regular checking of the paralel groups voltage I use single purpose instrument with precise voltmeter. 0,1 mV voltmeter.jpg Precise voltmeter has resolution 0,1 mV up to 4,3 V. There is also built-in precision 0,02% voltage refere...
by docware
Feb 20 2020 1:46am
Forum: Battery Technology
Topic: Li-ion cells cycle ageing
Replies: 472
Views: 49838

Re: Li-ion cells cycle ageing

.... and on most of my ebikes the only gauge I've used of any kind is a $2 digital voltmeter. Thanks for confirming that once you become accustomed to your pack's voltage as a measure of its SOC, that doesn't change with time despite the change in capacity. Just to confirm, that 50% SOC point is th...
by docware
Feb 19 2020 7:43am
Forum: Battery Technology
Topic: Li-ion cells cycle ageing
Replies: 472
Views: 49838

Re: Li-ion cells cycle ageing

Yes, those are rest voltage values. Testing protocol consist of 20 discharge 2 amp pulses , each pulse equals 5 % of the cell actual capacity (measured as a first step). 20 min rest time between discharge pulses. LG MJ1 SOC mapping 2A 292 s pulses.jpg In this example was LG MJ1 discharged by 2 A for...
by docware
Feb 19 2020 4:33am
Forum: Battery Technology
Topic: Li-ion cells cycle ageing
Replies: 472
Views: 49838

Re: Li-ion cells cycle ageing

SOC comparative table.
It´s obvious that SOC voltage distribution has no significant change after 700 cycles.
SOC% versus voltage - after 700 cycles  18.2.2020.jpg
SOC% versus voltage - after 700 cycles 18.2.2020.jpg (193.68 KiB) Viewed 1843 times
by docware
Feb 17 2020 11:52am
Forum: Battery Technology
Topic: Li-ion cells cycle ageing
Replies: 472
Views: 49838

Re: Li-ion cells cycle ageing

New batch of pictures : Samsung 30Q 472 cycles, LG MJ1 435 cycles, SONY VTC6 200 cycles, Samsung 21700 50E 165 cycles, Samsung 35E 125 cycles, LG HG2 64 cycles. 50E curve is obviously influenced by the ZKETECH failure. Samsung 30Q 472 cycles.jpg LG MJ1 435 cycles.jpg SONY VTC6 200 cycles.jpg Samsung...