Search found 135 matches

by Pajda
Feb 21, 2018 1:31 pm
Forum: Battery Technology
Topic: Inside an LEV50 prismatic cell
Replies: 5
Views: 169

Re: Inside an LEV50 prismatic cell

Great info, thanks jonescg :)
by Pajda
Feb 19, 2018 1:53 pm
Forum: Battery Technology
Topic: Tesla 18650 question
Replies: 16
Views: 371

Re: Tesla 18650 question

avoleoo: Nice graph and good to hear that you found the problem. In past I try lots of battery chargers as a battery testers and I was disappointend with most of them, even with FMA Powerlabs which measures significantly lower capacity. Now I am looking at BT-C3400 and that's the certainty of measur...
by Pajda
Feb 17, 2018 8:57 am
Forum: Battery Technology
Topic: Tesla 18650 question
Replies: 16
Views: 371

Re: Tesla 18650 question

I think there should be problem with your charger/tester. Because my Tesla 85kWh battery cell samples do not get significantly hot at 1C discharge rate. In fact thru my hands got a lot of 18650 cells and I cannot remember if at least one of them was significantly hot at 1C discharge rate. Also I hav...
by Pajda
Feb 17, 2018 8:03 am
Forum: Battery Technology
Topic: Samsung INR21700-48G
Replies: 31
Views: 2980

Re: Samsung INR21700-48G

Finally I got one tester channel free and start with cycle life test. It will take at least one month to get some initial results. But I have no problem with nominal capacity. On my calibrated 4-wire tester I got this results: Nominal capacity test*: capacity: 4.795 mAh, energy: 17.400 Wh My cycle l...
by Pajda
Feb 05, 2018 5:15 pm
Forum: Battery Technology
Topic: boston swing 5300 battery 3000 cycles
Replies: 18
Views: 1371

Re: boston swing 5300 battery 3000 cycles

I heard some rumors too, but from my own tests I do not find any significant problems yet. I am running cycle life test but I am now only at 150-300cycle depending on tested DoD and it is so soon to make qualified conclusions. But for now cycle life looks good, again especially for the price.
by Pajda
Feb 05, 2018 9:14 am
Forum: Battery Technology
Topic: boston swing 5300 battery 3000 cycles
Replies: 18
Views: 1371

Re: boston swing 5300 battery 3000 cycles

Sonata is "blue" cell with PTC (or another safety fuse) inside so it has significantly higher internal resistance and it is not good for ebike or another high power applications. Swing is "green" cell which we are talking about. The cycle life seems very good, as it is comparable to the best 18650 c...
by Pajda
Jan 26, 2018 2:25 am
Forum: Battery Technology
Topic: Quick BMS question for DIY battery pack
Replies: 3
Views: 148

Re: Quick BMS question for DIY battery pack

Amberwolf is right. MOSFET load/charge switch and onboard current measurement is used only for low voltage batteries up to 100V and currents up to 200A peak (ca 80A continuous). Also there is problem with industrial standards which forced you to isolate battery from the vehicle chassis when using "H...
by Pajda
Jan 24, 2018 4:01 pm
Forum: Battery Technology
Topic: New battery pack build.....25R, 30Q or VTC6?
Replies: 16
Views: 541

Re: New battery pack build.....25R, 30Q or VTC6?

From the perspective of long battery service life it is most important your average DoD. If your daily average is about 50% DoD it really does not much matter if you are charging the battery to 100% and all of those cells will do the job well. But if your daily average is 80% DoD or more I highly re...
by Pajda
Jan 20, 2018 2:17 pm
Forum: Battery Technology
Topic: LG HG2
Replies: 9
Views: 547

Re: LG HQ2

You mean LG HG2? I am not sure if LG HQ2 even exists. I have very good experiences with HG2 cell, it is one of the most robust cell in 18650 format. And one of few which is capable of fast charging without affecting cycle life. The standard charge rate for this cell is 0.5C and this gives you in 8p ...
by Pajda
Jan 16, 2018 5:59 pm
Forum: Battery Technology
Topic: Anyone actually used the Boston Power 5300mAh cells?
Replies: 9
Views: 344

Re: Anyone actually used the Boston Power 5300mAh cells?

I recently found price 4.28 USD with free shipping to US, EU for 100cells quote. That is 19.3Wh/4.28 USD = 220 USD/kWh. Not bad from my point of view 8)
by Pajda
Jan 16, 2018 3:20 pm
Forum: Battery Technology
Topic: Anyone actually used the Boston Power 5300mAh cells?
Replies: 9
Views: 344

Re: Anyone actually used the Boston Power 5300mAh cells?

Ah, I was looking into bad column, the continuous discharge rate is really 13A. But I must say that I am not doing cycle life test (at least for now) with more than 1C discharge rate. When designing the HE battery for long life (more than 2 years with the goal of 10 years life) I'm using a "0.5 aver...
by Pajda
Jan 16, 2018 11:15 am
Forum: Battery Technology
Topic: Anyone actually used the Boston Power 5300mAh cells?
Replies: 9
Views: 344

Re: Anyone actually used the Boston Power 5300mAh cells?

I apologize for this inappropriate remark. :oops: I'm trying to get an overview of all the currently available technologies of Li-Ion batteries on the market. But this manufacturer and the type of battery has long missed my attention. I had the prejudices that it was just another Chinese variation o...
by Pajda
Jan 15, 2018 5:13 pm
Forum: Battery Technology
Topic: Anyone actually used the Boston Power 5300mAh cells?
Replies: 9
Views: 344

Re: Anyone actually used the Boston Power 5300mAh cells?

Maybe because they have too good parameters for the common people?
by Pajda
Jan 14, 2018 3:41 am
Forum: Battery Technology
Topic: Samsung INR21700-48G
Replies: 31
Views: 2980

Re: Samsung INR21700-48G

Nice results. My samples of Samsung INR27100-48G cells, ready for cycle life test, are still laying on the table :( because I do not have any test channel free. Tesla and Boston cells gets the priority. But I am waiting for another 16 test channels till the end of January.
by Pajda
Jan 12, 2018 3:27 am
Forum: Battery Technology
Topic: MeanWell HLG vs ELG as charger
Replies: 16
Views: 437

Re: MeanWell HLG vs ELG as charger

Thank you for your experiences I will add HLG and ELG to my series of charging usable PSU. I have bad experience with Meanwell RSP-1000-12 DC-DC converter I wanted to use it as onboard charger for charging 12V battery from 100V traction battery in BEV. But I found that there is ca 3mA current flow f...
by Pajda
Jan 11, 2018 2:37 pm
Forum: Battery Technology
Topic: MeanWell HLG vs ELG as charger
Replies: 16
Views: 437

Re: MeanWell HLG vs ELG as charger

From my point of view the only difference between power supply (PS) and CC-CV charger is that charger should have reverse current protection. I think that both of this PS do not have this protection. The problem with PS without reverse current portection (or OR-ing protection) is that you cannot lef...
by Pajda
Jan 10, 2018 9:03 am
Forum: Battery Technology
Topic: Panasonic NCR18650GA disclosed specs, and 30Q Samsung cells
Replies: 17
Views: 677

Re: Panasonic NCR18650GA disclosed specs, and 30Q Samsung cells

LG HG2 can be charged at 4A (continous) per 18650 cell and will last for many hundred cycles under that conditions. (datasheet performance, not my own experience)) If you use it within a reduced SOC window it will last for thousands of cycles. I can confirm that with my own measurement. 100% DoD cy...
by Pajda
Jan 06, 2018 4:19 am
Forum: Items for Sale - Used
Topic: FS: Tesla Model S cells (Europe) (sold!)
Replies: 19
Views: 999

Re: FS: Tesla Model S cells (Europe)

Buk___ wrote:
Jan 05, 2018 4:00 pm
Pajda wrote:
Jan 05, 2018 1:11 pm
new NCR18650BM: capacity: 3.125 mAh, energy: 11.35 Wh
3000km Tesla P85D: capacity: 3.120 mAh, energy: 11.32 Wh
Presumably, those numbers are Ah, not mAh?
Of course, sorry for that. I have corrected the values to mAh and add a new setting with 1C discharge for cycle life test.
by Pajda
Jan 05, 2018 1:11 pm
Forum: Items for Sale - Used
Topic: FS: Tesla Model S cells (Europe) (sold!)
Replies: 19
Views: 999

Re: FS: Tesla Model S cells (Europe)

Today arrived a few cell samples from Boekel for my cycle life tests and comparsion with other industrial 18650 cells. For some time I was looking for cells with known history with the lowest possible mileage and calendar age. I have measured nominal capacity/energy at calibrated 4-wire battery test...
by Pajda
Dec 23, 2017 11:02 am
Forum: Battery Technology
Topic: Cycle life testing : LG INR18650 MJ1 vs Sanyo NCR18650GA
Replies: 16
Views: 2821

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

Thanks for this test results! Very useful for me.
by Pajda
Dec 23, 2017 10:55 am
Forum: Battery Technology
Topic: Any Tesla 18650 data sheets available from years gone by?
Replies: 18
Views: 748

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 ce...
by Pajda
Dec 23, 2017 8:02 am
Forum: Battery Technology
Topic: If you are building packs today, which cells to choose?
Replies: 73
Views: 5145

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

I can confirm that Samsung 35E and 30Q both have very poor cycle life at 100% DoD. But a surprise for me is Samsung 29E cycle life which is significantly better after 300cycles than Panasonic PF, where PF is one of the best cells in this parameter. Unfortunatelly I do not have results for more than ...
by Pajda
Dec 23, 2017 5:56 am
Forum: Battery Technology
Topic: Any Tesla 18650 data sheets available from years gone by?
Replies: 18
Views: 748

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

At what discharge rate? Isn't part of the Tesla secret sauce simply over-provisioning. The more cells, the lower the discharge rate for any given power draw; the longer the life. My test methods are 0,5C CC-CV charge rate @ 100mA cut-off (standard charge rate by most manufacturers - I use this valu...
by Pajda
Dec 22, 2017 3:07 pm
Forum: Battery Technology
Topic: Any Tesla 18650 data sheets available from years gone by?
Replies: 18
Views: 748

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. I can confirm that BM cells in my cycle life tests behave almost identical to the Tesla 85kWh battery cells. These cells are state of the art, not because of their initial...
by Pajda
Dec 11, 2017 2:24 pm
Forum: Battery Technology
Topic: The 3500mAh heavyweight division: Sanyo NCR18650GA vs Panasonic NCR18650GA vs LG MJ1 vs Samsung INR18650-35E
Replies: 25
Views: 1426

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

The heat generation and voltage sag are caused by the cell internal resistance (IR). You can choose two ways how to deal with this issue. You can use high power (HP) cells with low IR such as your mentioned Samsung 25R. Then you can operate at 3-5C average discharge current without significant effec...