mark kibort

what does voltage have to do with kwh costs? either you use and replace the electrons or you dont, right?

mk

SharkSkin

Jeff, how do you convert electricity to equivalent fuel? What is the AH capacity of your batteries?

Also I'm curious as to why you wouldn't add more batteries -- do you just not need additional range?

6mil928

I thought this car was a straight electric not a hybrid?

Bill Ball

Correct.

nsantolick

I could be wrong here, but I thought that going from 110/220 volts of household current down to whatever the individual batteries voltage is, would require less kwh's than you were thinking.

I have no doubt that the cost to run the car off of electricity is waaaaaaaaay lower than gas would be. My guess is somewhere around $4.00 for a full charge, assuming 25 cents per kwh...

I like experimental cars like this, and see the wisdom of them, but I heard that our current "grid" just can't handle any real quantity of electric cars without major work. It's interesting that some of the very first cars made were electric though.

From what I have read, I think I'd like to see mini-nuke-reactors being set up all over the place, and electric cars being used everywhere, but I wonder just how realistic that would be...

I do wonder about the whole "environmental cost" associated with the manufacture of the batteries, and the disposal problems with them... I heard that the materials used to make them are mined in Canada, and shipped all over Asia, during different stages of production, then back here. When you look at that, then factor in disposal problems, I wonder if it really makes much of a difference environmentally...

I'm not certain of any of those things, of course, but I mention them in case some one cares to offer their opinions. I'm curious...

I do love those fender skirts. The Citroen SM, a car that I've compared to the 928 in the past came with similar ones. I'm not big into modifications of the cosmetics of 928's, but dam, I wish the car had came with them.

Does anyone offer fender skirts for an S4 anyway???













Nick - Hazleton, Pa - 89 S4 Auto

6mil928

Ok then he's saying he can charge up the car 4 times for $2.25. If the 40 miles per charge is accurate. I'm getting the bull feeling on this one.

SharkSkin

A Watt is a measure of power that factors in voltage, but can be regarded as voltage-independent. Basically one watt is one volt at one amp. A kilowatt-hour is 1,000 watts for 1 hour, whether that's 1 volt at 1,000 amps or 1,000 volts at 1 amp.

So if you charge at 120v and 1 amp for 10 hours, then discharge at 12v and 10 amps for 1 hour, all of the power is accounted for(except for the fact that there are always losses, and I'm trying to keep it simple).

mark kibort

I think Dave said it best. I dont know what the capacity of the battery pack is.

He told me, but I forgot. all I remember is that it was a bunch of 12v lead acids in series for a pretty high operating voltage. they do this, as to drive down the current requirements (cheaper components, as usually higher amperage is more costly than higher voltage). Plus, batteries last longer when they are charged and discharged at a lesser current rate.

With the move to lithium Ion batteries, the weight will be reduced, but cost will go through the roof. However, enviromentally, the LiPo batteries are recyclable.
The charging of the batteries is a little more critical for their life expentancy.

If you look at the Tesla specs, you can see that the battery capacity. I think i did a rough estimation that its Lithium Ion packs could do the car's near 270hp for about half of a 30min race. (assuming full throttle for half a race) . I dont think the motors or the drive electronics could survive this without overheating, but it was interesting to look at and certainly gives a ball park of recharging costs, as well as all out performance. (270hp is like 200kw, so the capacity has to be around 100kw hours, which would be around $25 for a full charge)
voltage of their system is 375volts, and the batteries are made from 6800 individual lithium Ion cells. 60x 113series packs I guess.

mk

jmccabe

Lets see... my lithium pack will have a capacity of 25kw. of that 20k is usable at 80% discharge. If I charge off peak at 5 cents per kwh , thats around $1.00 for 100 miles.(thats 1 cent per mile) not bad Even if I charge mid day at 20 plus cents per kwh thats only $4.00 per charge

sorry.. no bull here,
Jeff

jmccabe

one reason why I dont add more lthium...money ....allot more money. Also uneeded weight I dont drive more than 40 miles a day.

Jeff

SharkSkin

Makes sense, Jeff. Why spend money to reduce acceleration?

mark kibort

Not bad at all. $4 for 40 miles is 10cents a mile, and not too far off gas prices and equiv. to about 25mpg. however, at off peak, thats like 100mpg. not bad at all!!

Now, when are we going to build the 928 electric race car! all we need is 100kwh batteries electronics that could survive 200kw with a 50%/10second duty cycle

mk

6mil928

Didn't think about the peak and off peak prices. No matter what an electric 928 is still an accomplishment.