The 1994 US Electricar factory conversions of S10 and Prizm had a selectable (as well as programmable) regen amount, it was possible to get an axle-crunching regen since a typical AC drive can generate a braking force greater than the max acceleration, for two reasons: - during acceleration, inefficiency in motor and drivetrain cause a lower power at the wheels than the max that the controller can develop, while during deceleration (regen) the losses work the other way: the power removed at the wheels is larger than the electrical power generated by the motor into the inverter, the deceleration force can easily be almost twice the acceleration force, for the same power going through the inverter! - secondly, during charging the battery voltage is higher than during discharging while many ocntrollers have a current limit only, so a higher pack voltage means higher power capability of the controller than during acceleration. The combination can cause the deceleration force to be easily more than twice the acceleration force, depending on pack voltage swing and efficiency of the drivetrain (motor + gearbox + diff + CV + ...)
Most factory EVs will limit the regen power to a fraction of what the controller can handle, to keep batteries within their spec'ed rate of charge Regards, 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 John Lindsay Sent: Friday, January 17, 2014 2:41 PM To: Electric Vehicle Discussion List Cc: Electric Vehicle Discussion List Subject: Re: [EVDL] BMW i3 Ross Blade's commercial conversions BEV.com.au used an Azure controller that does this style of regen. The first time someone drives it they usually trip the cutoff when they take their foot off the pedal. I rarely touch the brakes while in motion. John Lindsay > On 18 Jan 2014, at 1:37 am, Ben Apollonio <[email protected]> wrote: > > As far as I know, Tesla actually pioneered that approach to regen, but I've seen many reviews of the i3 where people think it's a novel idea. At first I didn't like the feel, but after further thought, it's far superior than the Prius model (light regen to simulate engine drag, plus additional regen on the brake pedal). Not only is driving smooth and easy, but you know exactly where the line is between regen and friction brakes. You also get a more responsive brake pedal. > > -Ben > > On Jan 16, 2014, at 4:22 PM, Rush Dougherty wrote: > >>> Indeed they did! I posted the controller from a 1902 Baker on my web page >> at >>> http://www.sunrise-ev.com/Controllers.htm. It had a compound motor, and >>> used both regenerative and dynamic braking. In fact, it had no mechanical >>> brakes! Just a mechanical parking brake. >> >> I drove the BMW i3 yesterday. It has very strong regenerative braking. The >> more you let up on the go pedal (what do we call the accelerator pedal for >> an EV?), the stronger the regen is. If you don't tailgate the guy in front >> of you, you don't need to brake, it will regen to a stop. And to 'coast', >> according to the display on the dashboard, there is no usage of the battery >> pack. >> >> I really liked it if only for that one reason. >> >> And it has Excellent acceleration... well, I also really liked the >> acceleration... >> >> Rush >> www.TucsonEV.com >> >> >> >> >> >> >> _______________________________________________________ >> Unlimited Disk, Data Transfer, PHP/MySQL Domain Hosting >> http://www.doteasy.com >> _______________________________________________ >> 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) _______________________________________________ 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)
