Run on the freeway at what speed? 65 mph? If so then that's about right.
On flat ground at 50 mph with no wind your car should draw about 100 amps give or take (educated guess). The power requirements are not linear, they go up as the square of the speed. That means that it takes approx 70% more power to go 65mph than it does to go 50mph. Throw in some wind or a gentle hill and it could easily be 200 amps at 65 mph. Now if you are drawing 200 amps at 45-50 mph then you have a problem (assuming you're not going uphill) Mark Dodrill wrote: >The main reason I think it's the motor where the problem is that it can >easily take 200+ amps to run on the freeway, even in the correct gear, and >it will get very hot (180+ degrees at the case) after doing that. > >Basically, I want to do two things: 1) Install a fan to help make sure the >motor stays cool, and 2) Try to determine how much loss I'm having with this >motor to try to determine how much more efficient my car would be with a 8" >ADC, instead of this one. > >By the way, I have my charging info on my web site: >www.dodrill.net\pulsar\Charge_Log.xls for the Excel spreadsheet, or >www.dodrill.net/pulsar/Charge_log.txt for the text version. Maybe looking >at that would give some wisdom... > >Thanks for the help. > >Mark > >-----Original Message----- >From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On >Behalf Of Chuck Hursch >Sent: Friday, September 27, 2002 11:34 PM >To: [EMAIL PROTECTED] >Subject: Re: How much power am I losing? > > >Mark Dodrill wrote: > >[snip] > >>Since it is a 6.7" ADC (a bit small for my car), I suspect that >> >I'm having > >>a lot of electricity turned into heating up the motor instead >> >of having > >>the motor run faster (since I'm at the upper end of the >> >power/torque it > >>will do). I'm wondering how I can measure this loss. If I >> >were to measure > >A small motor may not be so inefficient as you think. I'm >recalling that Mike Slominski's EV Rabbit (which was known to go >close to 125 miles on a charge with a 96V pack of Trojan T125s) >had a small ~7-in GE motor. Yeah, I know, there were a lot of >things that went into making that car more efficient, such as >less weight (2700lbs instead of the average 2800-3000lbs Rabbit >conversion weight), battery pack all in one big block (so less >temperature variation and better pack balance), driving >technique, etc. But do recall walking away with the impression >that higher voltage on a smaller motor may be better, within >thermal capacity limits of the motor. Something about the >windings being more fully saturated? Anybody know more about >this? > >Chuck Hursch >Larkspur, CA >www.geocities.com/nbeaa > > >
