914 EV discussion, Who's doing or done an electric 914? Options

[Joe Bob]

http://www.electroauto.com/gallery/vp914.shtml
http://electric914.wordpress.com/
http://www.evcl.com/914/

Electro Automotive has a kit for 14K...yikes.....
Otmar seems to be REAL busy building components.....

I'm thinkng of doing one for my twins..... (IMG:style_emoticons/default/blink.gif)
I have two years to get it done.....

[pjf]

I have to respectfully disagree with Banger's estimate of the cost per mile for an electric 914. The price of 20 6v lead acid batteries is more like $2000, not $3000. They are rated at 550 cycles at 80% degree of discharge which works out to $3.63 per charge. The pack will hold about 18kwh of electricity at .15/kwh equals $2.70. Total cost $6.33 for about 60 miles or $.1055/mile. Gas at $3 for 30mpg is $.10. Any estimate has some slop in it but I think electric cars using even low-tech batteries are now cost-effective.
The problem with the Ranger EV motor is that the converter is expensive and it runs at a much higher voltage. Higher voltage battery packs are more expensive.
I really doubt ElectroAutomotive's estimate of 100-150 miles. From the electricity usage numbers I got from someone running a car with the kit, it doesn't add up. AC systems are not that much more efficient. $15K for the ElectoAutomotive kit is steep, too steep for me. A DC system where you do things like build the battery boxes yourself can save you alot. I think the estimate is more like $8K. I haven't added up what I'll be spending but its not $15K I can tell you that.
I know that electric motors are rated with continuous HP rather than peak as is the case for gas engines but half the horsepower continuous is still not enough. I've asked someone who used the AC kit in a 914 and they agree. The flat torque curve is nice but it can't make up for the lower horsepower it would seem. DC motors can and are abused and in the extreme case racers get over 400hp from the 9" motor that I plan on using. I'm not going to go that far and with Otmar's controller are shooting for more like 200hp for short bursts.
I too think this will be a fun project. Good luck and let me know if I can help with anything.

[banger]

The price on Trojan T-105 batteries are around $150ea. This gives a pack cost of $3000 for 20. You could go for cheap wal-mart golf batteries, but then you get what you pay for. As for charging, the Trojans are rated at 220ah multiply this by 120v, and you get 26kw. Then take 80% of this and you have 20kw, now divide by the charger efficiency 94%, and you end up with 21.3kw. Multiply this by .15/kwh, and you get $3.15, then divide 50 miles, and you get 6.3 cents per mile for just the power.

The other problem has to do with the cycle life. If you have good batteries, and limit the depth of discharge, then you will get more cycles. But you also have to remember that the capacity is still declining with each cycle. Lead acid batteries last between 300 and 500 cycles. At this point you will be down to 50-60 percent of initial capacity. To prevent further damage to the battery, they should only be discharged to 80%. If you drive the vehicle every week day, and use only 1 cycle per day, then your batteries will last 18-24 months. If you drive it every day, then the time will be less. Also keep in mind that the batteries will decline with age whether they are used or not. The will also need to be charged as soon as they are used, since letting them sit will result in sulfation.

And for some background, I currently own 2 electric vehicles, and owned 2 others prior to the current ones. I have owned a 48V dc powered car, 120V DC powered truck and two 312v AC powered trucks. I can tell you all the ins and outs of owning and driving electric vehicles. My daily driver is 98 Ford Ranger EV, which gets driven around 30-40 miles per day.

I have to respectfully disagree with Banger's estimate of the cost per mile for an electric 914. The price of 20 6v lead acid batteries is more like $2000, not $3000. They are rated at 550 cycles at 80% degree of discharge which works out to $3.63 per charge. The pack will hold about 18kwh of electricity at .15/kwh equals $2.70. Total cost $6.33 for about 60 miles or $.1055/mile. Gas at $3 for 30mpg is $.10. Any estimate has some slop in it but I think electric cars using even low-tech batteries are now cost-effective.