Lee; As a builder/driver of a 65 Datsun truck for almost 6 years, I'd like to chime in on this.
When I first started design of my truck, I really considered making it direct drive based on the following: - Light weight, small frontal area, 4:88 rear end gears, 1200A Raptor controller. I ended up retaining the transmission based on a lot of comments against direct drive that I received from the list. In hindsight, I wish I would have gone without it. Besides the money saved on transmission repair, clutch, pressure plate, flywheel resurfacing, throw out bearing, adapter, etc, I would have also saved the weight, and more important rotational weight. As of today I'm averaging 247 Whrs. per mile for almost 200 trips I've driven the truck in 4th (1:00), checked brush temperatures, and haven't seen any issues. I can't imagine how better the performance would be without all of the rotational weight. I took identical trips using 3rd and 4th, versus only 4th and could not see any significant difference in Whrs. per mile. If I was doing another Datsun truck with 4:88 rear end gears, I would definately set it up as direct drive. Just make sure to have enough controller, 1000A or greater, and the battery pack to support it. I would probably put a cooling blower on the motor just to be safe. This could be set up on a thermostat, to only come on as needed. 2.5 years ago, I gave up the lead for a (50) cell pack of 180 Ahr Calb cells. Had to swallow real hard when purchasing, but It is sure fun having 80 - 100 mile range. My lead only gave me 25. It will also be cheaper in the long run, if I get the 2000 to 3000 cycles versus 400 for lead. Time will tell on that. Dennis Elsberry, MO ________________________________________ From: EV <[email protected]> on behalf of Lee Hart via EV <[email protected]> Sent: Saturday, May 28, 2016 10:52 AM To: Electric Vehicle Discussion List Subject: Re: [EVDL] Conversion planning EVDL Administrator via EV wrote: Alan Brinkman via EV wrote: >> Some of the older Datsun mini-trucks had a rear axle ratio that >> would have the drive shaft spinning faster and some conversions did >> without the transmission. The few I looked at on the EV Album had a >> 4.88 rear end. I also like the old Datsun mini-pickups. My first EV conversion was a 1974 Datsun pickup. It had a 4:88.1 differential as I recall. I used a surplus aircraft starter-generator as my motor. These tend to like high RPM, so this was a good ratio for it. I kept the clutch and transmission. As it turned out, the clutch wasn't needed, as I mostly left it in 3rd gear all the time. > I don't know if this will help, but most of the Comuta-Cars used a > 5.17 rear axle (Dana model 12). Some shipped to hilly regions had a > 6.83 axle (Dana model 18). For a direct drive on-road setup with a DC series motor, you will want something close to 5:1. That puts the motor RPM in a good range -- not so low that current is excessive, but not so high that there's no horsepower at freeway speeds. Most cars and trucks have much lower differential ratios (between 2 and 3). With them, you need to keep the transmission or some kind of gear reducer. Your transfer case might work, but I suspect it has straight-cut gears that would be noisy, and it might not be designed for sustained use at high RPM. > I had a 5.17 in mine and it was really too high a gear for the GE > motor they used, IMO. That's correct. The CitiCars had undersized motors for the application. A direct-drive EV requires a bigger motor, so it can provide the high starting torque needed at low speeds without a transmission, but still have sufficient horsepower at high RPM for high speeds. > An interesting option might be to try space-saver spare tires. These are crummy tires, only designed for emergency temporary use. If you want small cheap tires, try trailer tires instead. -- "IC chip performance doubles every 18 months." -- Moore's law "The speed of software halves every 18 months." -- Gates' law -- Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org Read EVAngel's EV News at http://evdl.org/evln/ Please discuss EV drag racing at 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 Read EVAngel's EV News at http://evdl.org/evln/ Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA)
