Oops, sorry I should have made clear that after reading the previous post, I triggered on the name HobbyKing...
Cor van de Water Chief Scientist Proxim Wireless Corporation http://www.proxim.com Email: [email protected] Private: http://www.cvandewater.info Skype: cor_van_de_water Tel: +1 408 383 7626 -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Michael Ross Sent: Thursday, December 19, 2013 12:46 PM To: Electric Vehicle Discussion List Subject: Re: [EVDL] Looking headway completed packs Cor, Who is them exactly? I am not sure in the context of this thread who you are referring to. Thx, Mike On Thu, Dec 19, 2013 at 3:41 PM, Cor van de Water <[email protected]> wrote: > One word of warning, > I have ordered a set of (admittedly cheap) LiPoly packs for my eBike > from them 2 years ago. > Since power requirements was not high, I settled for 10C packs of 4S > 10Ah. > When I received my 4 packs, one had a cell that was either completely > self-discharged or was never initially charged, it was at 0V. > Another pack had a different issue, I think it was a wire for the > BMS connector was not properly crimped or something like that. > The internal resistance of the cells was such that in order to get the > current required for 10C, you would need to charge to max cutoff (4.2V) > and then load the cells to 10C which would send them to around (and some > below) the min cutoff voltage (2.5V). In other words - these were at > best > 2 or 3C and even then there was more than 2x spread in voltage drop from > internal resistance between cells. > So, be aware of getting something from a company that can be a > hit-and-miss > as evidenced by many similar stories on the RC lists - they might have > improved since then, this was 2 years ago. I wasted $200 on a combined > 25.6V 20Ah pack that although serviceable in my eBike due to low power > requirement and my hand-balancing of the cells, would be unusable when > attempted to be used at actual 10C or unsupervised charging. > > Cor van de Water > Chief Scientist > Proxim Wireless Corporation http://www.proxim.com > Email: [email protected] Private: http://www.cvandewater.info > Skype: cor_van_de_water Tel: +1 408 383 7626 > > > -----Original Message----- > From: [email protected] [mailto:[email protected]] On > Behalf Of George Tyler > Sent: Thursday, December 19, 2013 12:12 PM > To: 'emf-evdl'; 'Electric Vehicle Discussion List' > Subject: Re: [EVDL] Looking headway completed packs > > After working on this 48V pack of 48 cells I am inclined to agree that > fewer > Calb cells is more attractive, you can get them from Evlithium too. The > headway cells (38120P with screw terminals) I bought from them were > cheaper > than buying direct from headway. The ones in this pack I am working on > have > welded tabs, not friendly to work on. You can get plastic holders for > these > cells that you build up like Lego, those with the straps and screw > terminals > are much nicer to work on, neat too. > I did look at calb, but the 38120P cells have a 20C discharge > rate, > to get the same allowable discharge current from calb you need something > above 100Ah I think it was. I have been looking at R/C packs from > Hobbyking, > you can get these in up to 130C discharge rating. I had a Diahatsu > charade I > was driving 5 kms to work and the same back, so I wanted a low capacity, > high rate battery. I had health problems so did not finish the project > though. > -- Put this question to yourself: should I use everyone else to attain happiness, or should I help others gain happiness? *Dalai Lama * Tell me what it is you plan to do With your one wild and precious life? Mary Oliver, "The summer day." 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) 550-2430 Land (919) 576-0824 <https://www.google.com/voice/b/0?pli=1#phones> Google Phone (919) 631-1451 Cell (919) 513-0418 Desk [email protected] <[email protected]> -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20131219/e5b9 8d0b/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) _______________________________________________ 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)
