View Single Post
Old 05-23-2012, 05:44 PM   #6 (permalink)
fb_bf
Electric MG Midget
 
fb_bf's Avatar
 
Join Date: Apr 2012
Location: Colorado
Posts: 48
Thanks: 0
Thanked 44 Times in 14 Posts
Quote:
Originally Posted by j8reign View Post
Thanks, much appreciated. At this point, I've located a very cheap source for LiFePo4 cells, or at least they seem fairly cheap, so my plan is to go with 48 cells, making a total of 153.6 V/160 AH/24.58 KWH... seems like a good setup? I've run the calculator @ EVsource and brought the projected weight of the vehicle up to 2200lbs. to allow for the weight of the battery pack, motor, and other components. The calculator projects that at 80% DOD, I'd get around 89.37 miles per charge. Does this seem correct to you? Thanks for the input!
Yes, that does sound very close. The weight will show up in around town driving. My route energy use calculator showed my daily commute energy use would change by 3% for every 100 lbs added or subtracted. That will vary with how much stops and starts you have. My pack seemed well balanced and that is why I got 112 miles out of it. I charge at 3.6 Volts tops, and stopped driving at 2.7 volts on my lowest cell while under 100 amp load. I would guess 144 volts and 160 to 180AH will also work very well. With a warp 9 impulse motor you'll be able to get about 92 ft-lbs torque at 550amps, and you can deliver that many amps out past 4000 RPM. The RPM limit is 5000, so you'd have full torque from 0 to very close to max RPM and stay very close to the 3C max current draw out of most LiFePo4 cells. What cells are you considering anyway?
__________________
Frank '77 Electric MG Midget www.electricmgmidget.com
  Reply With Quote
The Following User Says Thank You to fb_bf For This Useful Post:
j8reign (05-23-2012)