I did a similar approach as SteveS. I used the standard 47 tooth sprocket in the back with a 13 tooth driver, and used a gear reduction with a jackshaft to get the final GR into the 5s. This also solved the PMG-132 rotation issue... excessive brush wear is reported with CCW. Fianally this also allowed the motor to be placed higher in the chassis, and better battery placement/balance resulted.
Jeff On Fri, Nov 7, 2008 at 10:53 AM, SteveS <[EMAIL PROTECTED]> wrote: > Do you know what kind of current you pull no load (wheel off ground)? > > My bike is probably heavier; I'm probably heavier (190), and I think the > shaft drive is somewhat less efficient; but I don't think that's all enough > to explain the difference. > > Well in any case I don't think I have any good reason not to add a gear > reduction. When I built my E-mini-bike I tried to use a single gear > reduction and it barely would go after pushing it off stopped. When I added > a 3:1 jackshaft it actually started performing nicely. It made a huge > difference. > > - SteveS > > damon henry wrote: >> >> Your current numbers look much higher than I would have expected. Years >> ago when I first put together my motorcycle, after I had the motor and >> sprockets mounted, I took it out for a couple of test runs with a battery in >> my lap and a pair of jumper cables. With one 12 volt 16 ahr Hawker it >> pulled about 20 amps and barely crawled along at perhpas 1 -2 mph. Two >> batteries in series bumped the current up to about 40 amps and a brisk >> walking speed 3 in series up to around 80 amps although I don't think I ever >> let it get up to speed as the battery terminal started getting real hot and >> the jumper cable tried to weld in place before I could pull it off. Since >> there was no controller, the battery amps and motor amps were the same. >> The closest point of comparison between your chart and my experience is >> probably with me riding with the two Hawkers and you running at 5 mph. I >> was on the pavement and you in the grass so that counts for something, but >> to make the numbers easy, if my batteries were sagging to 20 volts and >> pushing 40 amps it took me about 800 watts to move at roughly the same speed >> you were going with 2667 watts. Something in your setup is much less >> efficient than mine. Typically 2667 watts would be enough to hold me >> cruising at 20+ mph. >> damon >> >> > Date: Fri, 7 Nov 2008 08:31:47 -0500 >> > From: [EMAIL PROTECTED] >> > To: listserv@electricmotorcycles.net >> > Subject: Re: [ElectricMotorcycles] BMW update - data >> > >> > I hope I'm not double-posting; I think the first email was sent from >> > the wrong address. Anyway.... >> > >> > I realized I should have taken data before taking my direct drive apart. >> > So I put it back together and connected my Palm AXEmon to the Alltrax. >> > This is all with a 36V pack made up of 3 12V Hawker SBS-60 (60 A-H) >> > SLAs. Here's what I found: >> > >> > MotI: Motor Amps >> > BatI: Battery Amps >> > Watts: Watts (Battery Amps x Battery Volts) >> > % : Percent throttle >> > Condition: I ran three tests: the motor by itself in the frame, motor >> > connected to drive train with wheel lifted up, and actual runs over >> > fairly flat grassy area >> > >> > MotI BatI Watts % Condition >> > 23 2.3 85 10 Motor only, no load >> > 32 8.0 290 25 same >> > 32 3.2 117 10 Motor,shaft,wheel raised up (no load) >> > 59 14.7 528 25 same >> > 312 78.0 2667 25 Running on flat grassy area - maybe 5 MPH >> > 473 165.5 5397 35 same, but faster speed - maybe 10 MPH >> > >> > I found it didn't take much to rail out the controller (500A). The >> > brushes were pretty warm after a few minutes of riding around at low >> > speed. >> > >> > Has anyone else taken data under no load? Do the numbers look >> > reasonable? >> > >> > Thanks, >> > >> > SteveS >> > >> > >> > >> > . >> > >> >> >> ------------------------------------------------------------------------ >> Get 5 GB of storage with Windows Live Hotmail. Sign up today. >> <http://windowslive.com/Explore/Hotmail?ocid=TXT_TAGLM_WL_hotmail_acq_5gb_112008> >> ------------------------------------------------------------------------ >> >> >> No virus found in this incoming message. >> Checked by AVG - http://www.avg.com Version: 8.0.175 / Virus Database: >> 270.9.0/1773 - Release Date: 11/7/2008 9:08 AM >> >> > > >
