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. -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of emf-evdl Sent: Thursday, 19 December 2013 12:32 p.m. To: Electric Vehicle Discussion List Subject: Re: [EVDL] Looking headway completed packs Buy direct from headway. http://www.headway-cn.com/index.html <http://www.headway-cn.com/index.html> Be warned, by the time you pay for shipping and any associated fees, you get a pack that has little or no warranty. Don't expect China to help deal with any warranty claims. After all is said and done, 38120S Headway cells aren't that much better than some CALB cells. Depending on how many Ah you need, if you can do 40/60/100, then CALB are a much better deal. You don't have to worry about all that bussbar. This is coming from someone who's built a few large packs using headway. I'd do it differently today. > On December 18, 2013 at 2:08 PM Peakfoto Digital Photo Still n Video > <[email protected]> wrote: > > > Where can I find completed headyway battery packs form china or something? > > I'm looking for 36 volts 8-10 ah pack . > > most amaercans dealers are spendy . > > _______________________________________________ > 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/20131218/6379 51e5 /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) _______________________________________________ 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)
