Search found 41 matches

by youyoung21147
Dec 02 2018 1:10pm
Forum: Battery Technology
Topic: Leaked : New 26 and 65Ah LG cell datasheets for EV - LG E63 (Renault Zoe) and C1.5S
Replies: 24
Views: 5542

Re: Leaked : New 26 and 65Ah LG cell datasheets for EV - LG E63 (Renault Zoe) and C1.5S

@TilmanBaumann The most optimized way to charge LiIon cells is to use constant polarization voltage (20 to 100mV). All EV manufacturers use this method as the base for their charging algorithms. That's why the LG datasheet is so specific about SoC vs OCV. Betwwen 10 and 30% SoC, the cells can take h...
by youyoung21147
Dec 02 2018 9:37am
Forum: Battery Technology
Topic: Leaked : New 26 and 65Ah LG cell datasheets for EV - LG E63 (Renault Zoe) and C1.5S
Replies: 24
Views: 5542

Leaked : New 26 and 65Ah LG cell datasheets for EV - LG E63 (Renault Zoe) and C1.5S

Hello, I just came across these 2 datasheets on QB's website. Both are clearly addressing the EV and residential storage market. E63 is ~240Wh/kg and C1.5S is ~170Wh/kg. It seems like the 65Ah model is the current (or future ?) Renault Zoe battery cell : the datasheet explicitely mentions 22 and 43k...
by youyoung21147
Feb 15 2018 5:55am
Forum: Battery Technology
Topic: DIY battery pack cooling
Replies: 14
Views: 2717

Re: DIY battery pack cooling

What I did on my 10S and 14S ebike packs is varnish the entire pack internals and close the ends with wire mesh. This allows air circulation in the pack and repells big debris. Rain/water can get in and out. Tested for 1 year without trouble and no corrosion ! Airflow is critical to quickly balance ...
by youyoung21147
Feb 15 2018 5:45am
Forum: Battery Technology
Topic: Voltage drop with acceleration
Replies: 7
Views: 1355

Re: Voltage drop with acceleration

Considering the effort you put in making these packs and the safety risks, I would first learn how to make a pack properly. You seem to have good DIY skills so here are some guidelines : - Cells must NEVER touch each other. Use spacers ("battery holder") instead. That's to prevent overheat...
by youyoung21147
Feb 15 2018 5:27am
Forum: Battery Technology
Topic: Samsung INR21700-48G
Replies: 37
Views: 8296

Re: Samsung INR21700-48G

@ElectricGod : your conclusion reach mine ! These cells are overpriced and useless. I think they are 35E chemistry fitted in a larger case : when you normalize numbers and curves proportional to the cells mass, you get the same (=poor) cycle life and slightly more saggy discharge curve. When you thi...
by youyoung21147
Jan 16 2018 12:46pm
Forum: Items for Sale - New
Topic: CHEAP NEW ORIGINAL 18650 BATTERY CELLS AND PACKS
Replies: 808
Views: 238193

Re: CHEAP NEW ORYGINAL CELLS 18650 SANYO GA 3500MAH

@tomjasz I have bought these cells from Tumich last year. I put one in accelerated testing 4.01 to 2.8V /6A. After 1100 cycles it was still giving >2800mAh under manufacturer test conditions. And in real life, my commuting ebike that has seen approx 60 cycles in a year still outputs 95% of its origi...
by youyoung21147
Jan 04 2018 12:26pm
Forum: Battery Technology
Topic: Samsung INR21700-48G
Replies: 37
Views: 8296

Re: Samsung INR21700-48G

@ElectricGod : good to see you took the plunge on these. What decided you on the 21700 format ?
by youyoung21147
Dec 23 2017 1:18pm
Forum: Battery Technology
Topic: Any Tesla 18650 data sheets available from years gone by?
Replies: 18
Views: 2231

Re: Any Tesla 18650 data sheets available from years gone by?

Thx youyoung21147 for clarification of your test cycle. I agree that your test is very specific and so it is deadly for cells with high internal resistance. The NCR18650B will be ruined soon but I believe that PF can show good results under your test. And I can highly recomend you to try a LG HG2 c...
by youyoung21147
Dec 23 2017 11:04am
Forum: Battery Technology
Topic: Any Tesla 18650 data sheets available from years gone by?
Replies: 18
Views: 2231

Re: Any Tesla 18650 data sheets available from years gone by?

(Also, you might want to watch Professor Jeff Dahn describing a testing schema that successfully categorises cells in minutes rather than hours days or weeks. I don't know how easy it is to reproduce his test equipement, but if you can it would be a huge time saver if you are doing this a lot.) Nic...
by youyoung21147
Dec 23 2017 10:44am
Forum: Battery Technology
Topic: Cycle life testing : LG INR18650 MJ1 vs Sanyo NCR18650GA
Replies: 18
Views: 10500

Re: Cycle life testing : LG INR18650 MJ1 vs Sanyo NCR18650GA

I stopped testing at ~1100 cycles. Interestingly the capacity retention under manufacturer's testing conditions is excellent. Less than 15% degradation in 1000 cycles. For LG MJ1 the Coulombic capacity degradation is predominant For Sanyo GA the internal resistance degradation is predominant The LG ...
by youyoung21147
Dec 23 2017 10:12am
Forum: Battery Technology
Topic: Any Tesla 18650 data sheets available from years gone by?
Replies: 18
Views: 2231

Re: Any Tesla 18650 data sheets available from years gone by?

The information about "excellent cycle life" sounds to me as advertising message when I compare my own 100% and 50% DoD cycle life tests of used Tesla 85kWh cells and NCR18650BM cells with other industrial NCA cells. Tesla cells shows almost the same capacity drop after 500cycles as NCR18...
by youyoung21147
Dec 22 2017 12:48pm
Forum: Battery Technology
Topic: If you are building packs today, which cells to choose?
Replies: 82
Views: 15662

Re: If you are building packs today, which cells to choose?

35E has very very bad cycle life ! And it sags a lot more under 10A discharge. Its initial capacity is the highet of the holy trinity GA MJ1 35E but after 20 cycles it becomes the worst.
by youyoung21147
Dec 22 2017 8:12am
Forum: Battery Technology
Topic: Dunk charger in boron nitride?
Replies: 7
Views: 793

Re: Dunk charger in boron nitride?

You want to use hBN or cubic ?

problem with encapsulation is that you will put thermomechanical stress on the components and end up with a failed charger in few months.

Better solution would be a sealed aluminium enclosure filled with oil at 90% (to accomodate thermal expansion in the remaining air)
by youyoung21147
Dec 22 2017 8:08am
Forum: Battery Technology
Topic: If you are building packs today, which cells to choose?
Replies: 82
Views: 15662

Re: If you are building packs today, which cells to choose?

Samsung 30Q for excellent high-rate performance during the whole life of the cell
Panasonic 18650BM for excellent cycle life, safety, overall performance and value (Tesla cell)
Sanyo GA for best initial performance but heavy internal resistance degradation over time
by youyoung21147
Dec 22 2017 8:03am
Forum: Battery Technology
Topic: Speculate what happened to my cells
Replies: 11
Views: 1419

Re: Speculate what happened to my cells

Wonder if I can puncture one and see what gas comes out then ;) What's the gas from overdischarge? If the cell suffered from overheating (probably not the case here), Hydrogen Fluoride may have been formed by thermal degradation of the LiPF6 electrolyte. So I would recommend you to NEVER smell batt...
by youyoung21147
Dec 22 2017 7:54am
Forum: Battery Technology
Topic: Need Help Selecting Battery for TSDZ2 36V 350W
Replies: 7
Views: 2847

Re: Need Help Selecting Battery for TSDZ2 36V 350W

Don't worry about the connectors ! Just cut the battery and motor wires and use whatever connector you want. I have XT90S on my bikes. They are large enough to disconnect using gloves, can handle 50A and best of all : they have an integrated resistor to prevent the spark during connection. About 2US...
by youyoung21147
Dec 22 2017 7:49am
Forum: Battery Technology
Topic: mean well rpb-1600, programmable charger ~1600w
Replies: 1
Views: 543

Re: mean well rpb-1600, programmable charger ~1600w

Good find !! The PMbus potentially means we can control this with an Arduino and use whatever charging strategies we want !

300USD is not shocking, power supplies are so expensive.
by youyoung21147
Dec 22 2017 7:40am
Forum: Battery Technology
Topic: boston swing 5300 battery 3000 cycles
Replies: 18
Views: 4227

Re: boston swing 5300 battery 3000 cycles

I have bought 6 of these cells and started testing them. Initial capacity was 5200mAh. 3000 cycles is probably a lie. Different versions of the datasheet show different cycle life graphs ! After 50 cycles they just look similar to brand cells, not better (not worse either !). The degradation is clea...
by youyoung21147
Dec 22 2017 7:26am
Forum: Battery Technology
Topic: tesla battery temp monitor
Replies: 3
Views: 846

Re: tesla battery temp monitor

In fact, Linear Technology has a more pragmatic approach to this. In their LTC680x application notes, they suggest using diodes in series/parallel to monitor individual cell temperatures. Each cell has its diode and a few diodes are placed in // to make a diode bank to be compared to others. Wheneve...
by youyoung21147
Dec 22 2017 7:20am
Forum: Battery Technology
Topic: Bridge-less PFC isolated 99% efficiency capable charger
Replies: 9
Views: 1657

Re: Bridge-less PFC isolated 99% efficiency capable charger

wiredsim wrote:
Dec 01 2017 7:10pm
This is probably a dumb idea, but would it be possible to design a drive controller that also operates as a charger?

Put AC back in the same way that Regen does?
The Renault Zoe also uses the inverter as fast battery charger. Don't know anything about its detailed implementation.
by youyoung21147
Dec 22 2017 7:17am
Forum: Battery Technology
Topic: Samsung INR21700-48G
Replies: 37
Views: 8296

Re: Samsung INR21700-48G

I have some of these 48G. Pretty uninteresting cell after all. It behaves exactly like the Samsung 35E, i.e excellent initial capacity, extremely poor cycle life and very high internal resistance (worse than 35E in fact). When you normalize the results by cell mass, their behavior is identical. Apar...
by youyoung21147
Dec 22 2017 7:11am
Forum: Battery Technology
Topic: Any Tesla 18650 data sheets available from years gone by?
Replies: 18
Views: 2231

Re: Any Tesla 18650 data sheets available from years gone by?

Tesla cells in the model S are clones of the the NCR18650BE and NCR18650BM cells. The BM is essentially a slightly improved BE. These cells are state of the art, not because of their initial capacity (which is average+) but because of their excellent cycle life, tight cell-to-cell dispersion, very p...
by youyoung21147
Dec 22 2017 7:04am
Forum: Battery Technology
Topic: Battery Failing Under Load?
Replies: 4
Views: 742

Re: Battery Failing Under Load?

I would suspect a faulty mid drive. There is no reason for your battery to suddenly work like crap unless many cells inside are disconnected and unbalanced. It could be a hall sensor fault, winding fault, wiring fault, bad solder joint on PCB, damaged MOSFET... Do you have the possibility to test th...
by youyoung21147
Dec 22 2017 6:53am
Forum: Battery Technology
Topic: The 3500mAh heavyweight division: Sanyo NCR18650GA vs Panasonic NCR18650GA vs LG MJ1 vs Samsung INR18650-35E
Replies: 30
Views: 16283

Re: The 3500mAh heavyweight division: Sanyo NCR18650GA vs Panasonic NCR18650GA vs LG MJ1 vs Samsung INR18650-35E

Perform the same test after 300 cycles and you will be surprised with the results !

GA is excellent in the first 50-100 cycles but the internal resistance rises so quickly that even an old 18650PF beats it after that.
by youyoung21147
Oct 13 2017 7:02am
Forum: Battery Technology
Topic: Boston-Power Swing 5300 Li-ion cell test
Replies: 129
Views: 22518

Re: Boston-Power Swing 5300 Li-ion cell test

Nice to see they have 2 flat sides ! Makes the pack more energy dense per unit volume and also easier to liquid cool ! Also the vent notch on side is a cool safety feature, at least the sidewall failure location is predictable. But the inside visible in this post : https://endless-sphere.com/forums/...