Re: [EVDL] pouch cells
Sounds like LTO cell to me. Not standard LMP or LCO. Maybe some LiFePO4 variant. That spec tells it cycles well which is nice for such use. EV is not one of those applications. Nothing new under the sun I'd say. -Jukka http://www.google.com/profiles/jarviju#about 2015-05-12 5:56 GMT+03:00 Bill Dube via EV ev@lists.evdl.org: Dial it back just a bit. No need to be abusive. On 5/11/2015 7:59 PM, Michael Ross via EV wrote: You provided nothing that would help us answer your question. Not even the name of the reseller or manufacturer. What kind of inquiry is that? If you won't tell us, or show us, then there can be no real answer. 4000 cycles at %90 dod This is a mostly meaningless specification. Taking lithium cells to 90% DOD does absolutely nothing bad to them. What might mess them up regarding DOD is if they were not consistent in their capacity and construction - so that they would not age well together for the life of the pack. What you want to know with certainty, is the voltage at 100% SOC (or somewhat lower for a factor of safety). And then the temperature beyond which the cells should not go when at a high SOC. You need to know the recommended high cutoff voltage that is sufficient to protect the cells regardless of temperature. You need to be sure your charger never pushes the cells beyond the max SOC%. If you do push voltage and SOC% higher you need to know the activation temperature of the system (positive electrode and electrolyte composition) and never let the pack exceed that temperature when the cells at at a high SOC%. What will the life of the cells be? Unless a thorough study using high precision coulometry has been performed, then you will mostly have no idea the expected life of the cells. Traditional testing tells you nothing much about the expected life. The old methods take far too long to give results and no one ever runs them long enough to get an estimate that is very certain. On Mon, May 11, 2015 at 9:00 PM, ken via EV ev@lists.evdl.org wrote: I saw some pouch cells that claim 4000 cycles at %90 dod. any one tested theses. How are they for $ vs. power density. ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA ( http://groups.yahoo.com/group/NEDRA) ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA ( http://groups.yahoo.com/group/NEDRA) -- next part -- An HTML attachment was scrubbed... URL: http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20150512/1a6cb19c/attachment.htm ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
Re: [EVDL] pouch cells
http://www.electriccarpartscompany.com/-NEW-ENERGY-br-4000-CHARGE-CYCLES--20-AH_c_138.html I saw some pouch cells that claim 4000 cycles at %90 dod. any one tested theses. How are they for $ vs. power density. ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
Re: [EVDL] pouch cells
On May 12, 2015, at 12:33 PM, ken via EV ev@lists.evdl.org wrote: How are they for $ vs. power density. Middle of the road, and a lot more than a LEAF battery from Hybrid Auto Center. They're also rather below average in terms of $ / max discharge rate, and on the heavy side. b ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
Re: [EVDL] pouch cells
They are LFP so you have to be careful not to have them at 100% SOC and over 104°F or so. This will damage them. They suggest a charge up to 3.65V. I think that is too high. Guessing, anything over 3.45V is nearly pointless and just puts the cell in a more reactive (a bad thing) chemical state. They don't tell enough about the cycle life to guess what your actual cycle life will be. To run 4000 cycles, the cycle times were no where near the length of real life. A 1 hour cycle would take 167 days to complete. Probably the testing was at room temperature, which does not stress them at all. If you don't stress the cells then it doesn't tell you much, because nothing really goes wrong at 25°C. Your best bet is to stop charging them at a lower voltage (plan on less capacity). If you think the cells are going to be fully charged, then discharge them some if they are going to sit in a hot place. Cell temperatures will be higher than ambient - so again, you can't have them at a high SOC and in hot weather. Go up a steep hill fast, soon after you start riding; unless you know the charging cut off voltage is low and accurate. On Tue, May 12, 2015 at 3:33 PM, ken via EV ev@lists.evdl.org wrote: http://www.electriccarpartscompany.com/-NEW-ENERGY-br-4000-CHARGE-CYCLES--20-AH_c_138.html I saw some pouch cells that claim 4000 cycles at %90 dod. any one tested theses. How are they for $ vs. power density. ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA ( http://groups.yahoo.com/group/NEDRA) -- To invent, you need a good imagination and a pile of junk. Thomas A. Edison http://www.brainyquote.com/quotes/quotes/t/thomasaed125362.html A public-opinion poll is no substitute for thought. *Warren Buffet* Michael E. Ross (919) 585-6737 Land (919) 576-0824 https://www.google.com/voice/b/0?pli=1#phones Google Phone (919) 631-1451 Cell michael.e.r...@gmail.com michael.e.r...@gmail.com -- next part -- An HTML attachment was scrubbed... URL: http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20150512/aa022408/attachment.htm ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
Re: [EVDL] pouch cells
They also offer pouch cells, but this battery is aluminum encased so not a pouch. Cor van de Water Chief Scientist Proxim Wireless office +1 408 383 7626 Skype: cor_van_de_water XoIP +31 87 784 1130 private: cvandewater.info www.proxim.com This email message (including any attachments) contains confidential and proprietary information of Proxim Wireless Corporation. If you received this message in error, please delete it and notify the sender. Any unauthorized use, disclosure, distribution, or copying of any part of this message is prohibited. -Original Message- From: EV [mailto:ev-boun...@lists.evdl.org] On Behalf Of ken via EV Sent: Tuesday, May 12, 2015 12:34 PM To: Jukka Järvinen; Electric Vehicle Discussion List Subject: Re: [EVDL] pouch cells http://www.electriccarpartscompany.com/-NEW-ENERGY-br-4000-CHARGE-CYCLES--20-AH_c_138.html I saw some pouch cells that claim 4000 cycles at %90 dod. any one tested theses. How are they for $ vs. power density. ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA) ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
Re: [EVDL] pouch cells
On 05/12/2015 04:48 PM, Cor van de Water via EV wrote: They also offer pouch cells, but this battery is aluminum encased so not a pouch. I thought pouches were soft sided things and could be encased in a ridged housing. ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
Re: [EVDL] pouch cells
Got a link ? ( thanks ) On Mon, May 11, 2015 at 8:00 PM, ken via EV ev@lists.evdl.org wrote: I saw some pouch cells that claim 4000 cycles at %90 dod. any one tested theses. How are they for $ vs. power density. ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA ( http://groups.yahoo.com/group/NEDRA) -- next part -- An HTML attachment was scrubbed... URL: http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20150511/d7844bf7/attachment.htm ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
Re: [EVDL] pouch cells
You provided nothing that would help us answer your question. Not even the name of the reseller or manufacturer. What kind of inquiry is that? If you won't tell us, or show us, then there can be no real answer. 4000 cycles at %90 dod This is a mostly meaningless specification. Taking lithium cells to 90% DOD does absolutely nothing bad to them. What might mess them up regarding DOD is if they were not consistent in their capacity and construction - so that they would not age well together for the life of the pack. What you want to know with certainty, is the voltage at 100% SOC (or somewhat lower for a factor of safety). And then the temperature beyond which the cells should not go when at a high SOC. You need to know the recommended high cutoff voltage that is sufficient to protect the cells regardless of temperature. You need to be sure your charger never pushes the cells beyond the max SOC%. If you do push voltage and SOC% higher you need to know the activation temperature of the system (positive electrode and electrolyte composition) and never let the pack exceed that temperature when the cells at at a high SOC%. What will the life of the cells be? Unless a thorough study using high precision coulometry has been performed, then you will mostly have no idea the expected life of the cells. Traditional testing tells you nothing much about the expected life. The old methods take far too long to give results and no one ever runs them long enough to get an estimate that is very certain. On Mon, May 11, 2015 at 9:00 PM, ken via EV ev@lists.evdl.org wrote: I saw some pouch cells that claim 4000 cycles at %90 dod. any one tested theses. How are they for $ vs. power density. ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA ( http://groups.yahoo.com/group/NEDRA) -- To invent, you need a good imagination and a pile of junk. Thomas A. Edison http://www.brainyquote.com/quotes/quotes/t/thomasaed125362.html A public-opinion poll is no substitute for thought. *Warren Buffet* Michael E. Ross (919) 585-6737 Land (919) 576-0824 https://www.google.com/voice/b/0?pli=1#phones Google Phone (919) 631-1451 Cell michael.e.r...@gmail.com michael.e.r...@gmail.com -- next part -- An HTML attachment was scrubbed... URL: http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20150511/a1bbd41c/attachment.htm ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
Re: [EVDL] pouch cells
Dial it back just a bit. No need to be abusive. On 5/11/2015 7:59 PM, Michael Ross via EV wrote: You provided nothing that would help us answer your question. Not even the name of the reseller or manufacturer. What kind of inquiry is that? If you won't tell us, or show us, then there can be no real answer. 4000 cycles at %90 dod This is a mostly meaningless specification. Taking lithium cells to 90% DOD does absolutely nothing bad to them. What might mess them up regarding DOD is if they were not consistent in their capacity and construction - so that they would not age well together for the life of the pack. What you want to know with certainty, is the voltage at 100% SOC (or somewhat lower for a factor of safety). And then the temperature beyond which the cells should not go when at a high SOC. You need to know the recommended high cutoff voltage that is sufficient to protect the cells regardless of temperature. You need to be sure your charger never pushes the cells beyond the max SOC%. If you do push voltage and SOC% higher you need to know the activation temperature of the system (positive electrode and electrolyte composition) and never let the pack exceed that temperature when the cells at at a high SOC%. What will the life of the cells be? Unless a thorough study using high precision coulometry has been performed, then you will mostly have no idea the expected life of the cells. Traditional testing tells you nothing much about the expected life. The old methods take far too long to give results and no one ever runs them long enough to get an estimate that is very certain. On Mon, May 11, 2015 at 9:00 PM, ken via EV ev@lists.evdl.org wrote: I saw some pouch cells that claim 4000 cycles at %90 dod. any one tested theses. How are they for $ vs. power density. ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA ( http://groups.yahoo.com/group/NEDRA) ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
