I never have tried it but I am told that universal joints in a automobile drive cannot survive the side stress of a 109 HP electric motor (One AC-51) so you cannot put a sprocket on the drive shaft...
Dennis Lee Miles (*[email protected] <[email protected]>)* * Founder: **EV Tech. Institute Inc.* *Phone #* *(863) 944-9913 (12 noon to 12 midnight Eastern US Time)* *Educating yourself, does not mean you were **stupid; it means, you are intelligent enough, **to know, that there is plenty left to learn!* * You Tube Video link: http://youtu.be/T-FVjMRVLss <http://youtu.be/T-FVjMRVLss> * On Fri, Jul 25, 2014 at 8:07 PM, Cor van de Water via EV <[email protected]> wrote: > Ben, > It is not the motor asking for a certain amount of electricity, > the setup: battery - controller - motor > places the motor in the dependent position, how much that the > *controller* allows to flow from the battery. > So, the short of it is that if the battery cannot deliver as much as the > motor could be taking, then it is the task of the controller that limits > the current (or voltage) to the motor. This means - *you* need to > program the controller to limit the output to the motor to a safe level > for both > motor and batteries. > NOTE that if the batteries are capable of delivering more power than the > > motor can handle, again it is the controller that regulates a safe > amount to be delivered, though the controller can be setup to deliver an > instantaneous large amount and throttle back to avoid overheating or > otherwise damaging the motor. > > Direct Drive tends to "lug" the motor, meaning: low RPM and high torque. > Torque is produced from current through the motor. > > NOTE that for high motor current, it is not required that the batteries > are capable of the same current, as the controller can "multiply" > current at lower output voltage, so the controller and motor must be > capable of handling high current for a direct drive setup, or else you > will be very disappointed by the result. > > For example, if the motor is capable of "only" carrying a peak 1000A > while the voltage on the motor is always below 30V because it is running > at such low RPM, then there is no way to force the motor to deliver more > than 30kW > even though your battery pack may be 144V and 200kW! > Note that if you can put a 2:1 gearing between motor and shaft, your > current goes down 2x and voltage goes up 2x so that means 500A 60V, much > more reasonable! > > If your motor allows a peak of 2000A and at the normal driving speeds > can > take aound 50V then you are already in the 100kW range, but now there > are very few controllers that can dish out 2000A, in fact I only know > one affordable version and it is the Zilla 2K which is a DC controller. > For direct drive it will likely need a pretty beefy DC motor, especially > the brush setup needs to survive the 2000A currents, but drag racers > have shown that it can be done. Forced cooling of the motor and brushes > is a must! > > My previous EV was a US Electricar truck that was a factory converted > S10. > It retained the manual gearbox but there was no stick - the box was > permanently locked in 2nd gear as a fixed reduction, so that the entire > setup allowed the AC motor to spin faster, 1000 RPM for each 8 MPH. > The truck topped out at 72 MPH since the motor redline was 9k RPM. > > I am guessing that the question is if you can place the electric motor > *before* the transmission? > Or find the highest reduction diff for your Mustang that you can find, > you need to keep the Revs up to keep the electric motor alive! > > Another alternative would be to place the electric motor next to the > drive shaft with a sprocket on the motor axle pointing forward (next to > the output from the transmission) and a 4x larger sprocket on the > transmission output. > That 4x reduction from the motor will allow you to spin the motor at a > decent RPM because the drive shaft typically does around 1k RPM at > freeway speed, so your motor is then doing 4,000 RPM. If that reductoin > is built-in to the motor, all the better. > > Success, > > 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: Ben Goren [mailto:[email protected]] > Sent: Friday, July 25, 2014 4:21 PM > To: Cor van de Water; Electric Vehicle Discussion List > Subject: Re: [EVDL] Hybrid Mustang: batteries > > On Jul 25, 2014, at 3:21 PM, Cor van de Water via EV <[email protected]> > wrote: > > > Why on the world would you need over 200kW unless you are doing a race > > car? > > Well, each AC-51 is rated for ~80 kW; I'm assuming a pair is ~160 kW -- > which is about the same as the 260 motor in the car already. Seemed to > me that that it doesn't make sense to have the motor(s) wanting more > electricity than the batteries can deliver, so I've been trying to reach > at least 180 kW...but maybe that's not the way I should approach this? > > Um...maybe I should back up again. > > The only practical place to add an electric motor is along the > driveshaft, after the transmission and before the differential -- which > means a direct-drive setup. It's my understanding that that means lots > of electric motor to be able to live with the gear ratios, with a pair > of AC-51s or WarP 9s as the likely candidates. Based on that, I assumed > that the batteries would, in turn, have to supply as much electricity as > the motors could take -- else there wouldn't be a need for so much motor > in the first place. > > > My suggestion: use half your pack size (are there 90 Ah cells that you > > can use instead of 3 strings of 60?) which gievs half the cost and > > capacity, as you indicated that is what you need. > > See, this is why I'm bugging y'all. As many times I've been over the > various pages, I've often been looking for something different each > time, and I've apparently missed something yet again. <sigh /> > > No 90 Ah cells are leaping out at me with a quick search, but I now see > CALB 70 Ah 10C cells for $80.40 here: > > http://www.electriccarpartscompany.com/70Ah-32V-10C-br-SE70AHA-br-CALB-E > V-Lithium-LiFePO4-Prismatic-Cell-Batteries-br-USA-or-China-Stock-br-44L- > 24W-81H-in-br-113-60-206-mm-br-55-lbs-25-kg_p_287.html > > Two strings of 45 gets 200 kW with 20 kWh at 500 pounds for $3900 -- > something *much* more reasonable than anything I had calculated earlier. > > So...maybe this isn't hopeless after all. Thanks! > > ...and now back to do yet still even more research.... > > 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) > > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20140725/02428375/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)
