Thanks Russell, this is apparently exactly your line of research... Sometimes I forget to do the most obvious search, but you know in the age o= f automated computer 'intelligence' the human interface is highly appreciated= ! I will take some time to review the links you compiled for me and the searc= h results too. Really the most minimal way im proposing could even be accomplished with very few conventional components (Capacitor, FETs, diodes= , transistors). For example whenever the Battery reaches above a certain lega= l voltage the FET would be turned on to charge the Capacitor, if in turn it drops below a certain threshold it should switch of. If the Capacitor which could be the direct external connection of the cell ever gets discharged completely a diode (in the worst case) could prevent it from going too negative (would an electrolyte Cap self destruct with a small negative voltage?). I also like to hear comments about the general approach and requirements if a wide range of input voltages was supposed to be able to drive an EV (E-Bike is what I am designing for). Part of my own doubts are about the maximum current requirement when going uphill etc. Part of the issue is that I am starting to evaluate some inexpensive Chines= e LION cells, and of course my frustration with the stock controller that my e-bike (SX 36V) came with that has no flexibility around the original desig= n voltage! For the Bike I am now designing (inspired by Blade04 and erockit) http://www.youtube.com/watch?v=3DYPHThtr5GME http://www.youtube.com/watch?v=3DtzsHFka92X8 I don't even want to deal with battery sales, but leave that to a creative aftermarket! However the controller and motor needs to be specified right from the start! So here is the invitation to contribute and participate in the project! On Sat, Dec 18, 2010 at 7:09 AM, RussellMc wrote: > Just plugging > > High Voltage Redundant Cells EV Battery Controller > > into Gargoyle produced some remarkably good starting points > > ___________________ > > Lithiuate / Lithiumotive > DIY controllers. > Book > .. > > http://elithion.com/blog/ > > _____ > > An Intersil IC which sounds like it could have been designed in response = to > your spec > Announced November 2010 > > > > http://www.powersystemsdesign.com/intersil-introduces-hybrid-and-electric= -vehicle-hevev-li-ion-battery-management-control-solution?a=3D1&c=3D1153 > > http://www.greencarcongress.com/2010/11/intersil-20101105.html > > > > http://www.typepad.com/services/trackback/6a00d8341c4fbe53ef0133f59bd1439= 70b > > http://www.intersil.com/pr/shell/0,1091,2042,00.html > > http://www.intersil.com/auto/EV_HEV.asp > > Intersil Cell Balancing System > > Intersil's HEV/EV system solution features an automotive grade Li-Ion > battery management system and safety monitor. The automotive grade > (AEC-Q100), ISL78600 multi-cell solution is specifically designed and > tested > to address the safety, reliability and performance requirements of the > hybrid, plug-in hybrid (PHEV) and electric vehicle markets. > > Intersil's HEV/EV solution provides customers with ISO26262 (ASIL) > compliance to prevent battery pack failures. The solution also provides > built-in fault detection for all of its major internal functions and > detects > external faults such as open wire, over and under voltage as well as > temperature and cell balancing faults. > > The benefits offered by the Intersil HEV/EV system solution can > significantly reduce overall battery management system costs. > > What Tesla do > August 2006 > > > > http://webarchive.teslamotors.com/display_data/TeslaRoadsterBatterySystem= ..pdf > > LT read your mind > > http://www.edn.com/contents/images/6648791.pdf > > Nat Semi try to too > Large LiIon battery pack balancing > Part 2 > > > > http://www.automotivedesign-europe.com/en/large-li-ion-battery-packs-acti= ve-balancing-improves-many-parameters-part-2.html?cmp_id=3D71&news_id=3D222= 901231 > > > TI related and other. > App note black hole > > http://focus.ti.com/lit/ml/szza058/szza058.pdf > > * > Maxim evaluation kit et al > > http://www.maxim-ic.com/datasheet/index.mvp/id/6882 > > > * > > E. F. Piene, "Grid Connected Vehicles Capabilities and Characteristics," = in > Electric Vehicle Integration Into Modern Power Networks, DTU, Copenhagen, > 2010 > Really annoying ebook otherwise almost useful45 page presentation login > with > facebook to download move along there are easier ways to do this > presentation > > > > http://www.slideshare.net/EamonKeane/01-egil-falch-piene-grid-connected-v= ehicles-capabilities-and-characteristics-think-ef-piene20101 > > > > Whoops > !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! > Getting it wrong / lifetime > > http://www.mpoweruk.com/reliability.htm > > > E3 Car initiative > > > > http://www.ict4fev.eu/public/documents/dg-infso-cluster-event-2010/projec= ts/05_E3CAR.pdf > > > > Related > > http://www.ridemission.com/evt/drive-systems > > LiPo cells > MANY variants > > > > http://www.eemb.com/Li-Polymer_battery.html?gclid=3DCNLt9-6G9qUCFQRvbAodz= iZnqA > > > > > Russell McMahon > > > > _________________ > > ON Semi paper May 2009 > > On 18 December 2010 08:47, Tobias Gogolin wrote: > > > Proposing High Voltage Redundant Cells EV > > Have been thinking about the challenges and potential solutions for > > imperfect batteries and high reliability and range! > > > > I put together some criteria for a electric vehicle like it would like = to > > design or see available (ideally as an open source community project) > > > > - Add or remove batteries new and old without having to worry or balanc= e > > them all into a simple series chain! > > - Have every battery with its own intelligent charge and discharge > monitor > > that can bridge out that battery if it is too discharged or has reached > > full > > charge > > - Have the motor controller have a large range of voltage that it can > > switch > > toward the motor > > - Recuparative breaking charges a capacitor and a switching power suppl= y > > ups > > this to the voltage of the battery chain and its parallel buffer > capacitor. > > - Having a higher voltage chain keeps size of wires and switching FET > > losses > > smaller > > - have battery monitor circuits comunicate via a serial link possibly > > modulated in its current path > > > > I might be forgetting some, but I would like to receive comments and > > suggestions ASAP > > > > Thanks Tobias > > > > > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > --=20 Tobias Gogolin Tel. Movistar (646) 124 32 82 Tel. Telcel (646) 160 58 99 skype: moontogo messenger: usertogo@hotmail.com Blog: http://zeitgeistensenada.blogspot.com/ You develop Sustainable Ranch Technology at http://tech.groups.yahoo.com/group/SURA-TECH an Open Source Electric Motor/Alternator at http://groups.yahoo.com/group/Performance_Axial_Flux and an Open Source Motor Controller at http://groups.yahoo.com/group/GoBox --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .