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jmead

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I would think you could get a lot of efficiency by running a diesel engine at its peak efficiency into a generator turning its peak rpm which in turn would supply the propulsion. Pretty much eliminating batteries entirely except for quick bursts. I guess that is what you guys are trying to get at though. How much does a diesel generator weigh?

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Hmm... if these numbers add up, does this mean we could do around 70 miles to the gallon without ever plugging it in?

 

Why would you want to? If you can drive 50 miles for $1 in electricity, or $2.50 in diesel fuel, why would you ever want to use the fuel? Unless you were traveling long distance and carrying enough electricity isn't feasible.

 

Is plugging in that big of a problem? Why is plugging in a huge hassle, but driving to a gas station, waiting in line, pumping this smelly fluid whose fumes cause cancer and are extremely flammable is the better of the two choices? I don't get it, I wont miss filling up every few days at all.

 

Ok, for some reason a part of me doesn't want to believe it'd really be that efficiant, because if so we could reduce the battery weight significantly and just run it mostly off a generator and still get insane milage, and the distance able to be traveled would compare or BEAT the average car. You'd only need a 5 gallon tank to give you a significant range, and reducing the battery size would help offset the weight of the generator and gas tank.

 

This efficiency isn't anything special, it only seem like it compared to the horrendously inefficient vehicles we are used to. Its important to note this figure it based on 50mph, at 70 its probably half that. Air resistance goes up as the square of your speed, so there is a gigantic difference in the power required to drive 60 vs 80. That isn't much better than what a geo metro can get driven at the same speed, without any electric assist at all. Even in my car rated 32mpg highway if I slow down to 50mph I can get in excess of 45mpg, and its a 3000 lbs non-aerodynamic box, with an engine 20x bigger than necessary to maintain this speed.

 

A prius driven by a energy conscious individual can get over 100mpg without ever being plugged in.

 

The generator is really an afterthought for that 2% of the time when the batteries aren't enough to get where I'm going, I see no reason to use it more than is needed.

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I would think you could get a lot of efficiency by running a diesel engine at its peak efficiency into a generator turning its peak rpm which in turn would supply the propulsion. Pretty much eliminating batteries entirely except for quick bursts. I guess that is what you guys are trying to get at though. How much does a diesel generator weigh?

 

This is the basis for much of the efficiency increase over a typical car engine running at a fraction of its peak output most of the time. A small engine can run at peak constantly, can be smaller, weigh less, can be tuned for use at that particular speed increasing effeciency even more. But if you look at total fuel burned vs total distance traveled the batteries are going to win every time (including fuel used to generate your electricity)

 

The electric motor/batteries are over 80% efficient, all the time

 

An engine is at most 30% efficient, peak.

 

The goal is not to eliminate the need for batteries. It is to eliminate the need for an engine. Once I can afford a 30kwh pack of LiFePO4 that generator is toast, and I'll never look back. If I didn't commute over 50 miles every day, and have a girlfriend that lives 90 miles round trip away during the year, 300 miles during the summer I wouldn't even consider it.

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The generator is really an afterthought for that 2% of the time when the batteries aren't enough to get where I'm going, I see no reason to use it more than is needed.

 

I was thinking from a weight stand point. I totally understand and agree with your reasoning to keeping it 100% electric only most of the time, for those that want to either keep the weight down or travel farther distances a generator would give you a great range with possibly better effiency than a similarly powered petrol engine.

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I was thinking from a weight stand point. I totally understand and agree with your reasoning to keeping it 100% electric only most of the time, for those that want to either keep the weight down or travel farther distances a generator would give you a great range with possibly better effiency than a similarly powered petrol engine.

 

From the power per unit of weight perspective an engine can't be beat.

 

One pound of gas contains 17500 BTU of energy, which is about 308,000 watt/minutes, or 5,133 watt/hours. My whole 720 lbs pack of batteries holds 10,500 watt/hours, or about the same as 2 lbs of gas. 1 Gallon weighs 6 lbs, so my batteries hold the equivalent energy of 1/3 a gallon of gasoline.

 

But I can travel 50 miles on that amount of energy, where a gas car that gets 30mpg can only travel 10 miles.

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I really love the idea and it does seem to be that complicated . Id try that in a samll size pickup like a nissan or any other small size pick up being able to place some batteries up front and some in the bed would be very nice . Use the electric car for short distance and the gas powered for long trips . Id be worried about water splashing under the car and winter at -40 celsius though .

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Here's another reason to convert to electric drive: No more exhaust fumes entering the car. Unless, of course, you're running a genset. jmead and others doing this conversion, I applaud your efforts, and I considered this at one time, but for my purposes (I need my Z to be able to travel long distances) I need to find a clean-running, fuel efficient gasoline engine to replace my tired out, stinky, gas guzzling L-28. But keep up your good work, as batteries are improved upon, you'll be able to improve the range of your EVZs. BTW, have you considered Optima batteries? They might save a considerable amount of weight, and they can be mounted on their sides. On the other hand, their cost is about twice that of lead-acid batteries.

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Here's another reason to convert to electric drive: No more exhaust fumes entering the car. Unless, of course, you're running a genset. jmead and others doing this conversion, I applaud your efforts, and I considered this at one time, but for my purposes (I need my Z to be able to travel long distances) I need to find a clean-running, fuel efficient gasoline engine to replace my tired out, stinky, gas guzzling L-28. But keep up your good work, as batteries are improved upon, you'll be able to improve the range of your EVZs. BTW, have you considered Optima batteries? They might save a considerable amount of weight, and they can be mounted on their sides. On the other hand, their cost is about twice that of lead-acid batteries.

 

Optimas don't have the storage capacity needed. The lead acid batteries that are used in most cases are not the size of a conventional underhood battery, but about 3 times that size, physically.

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Here's another reason to convert to electric drive: No more exhaust fumes entering the car. Unless, of course, you're running a genset. jmead and others doing this conversion, I applaud your efforts, and I considered this at one time, but for my purposes (I need my Z to be able to travel long distances) I need to find a clean-running, fuel efficient gasoline engine to replace my tired out, stinky, gas guzzling L-28. But keep up your good work, as batteries are improved upon, you'll be able to improve the range of your EVZs. BTW, have you considered Optima batteries? They might save a considerable amount of weight, and they can be mounted on their sides. On the other hand, their cost is about twice that of lead-acid batteries.

 

Optimas were my choice originally, but after doing some research I found they have been having quality control issues and were not performing as well as they did originally. The Odyssey batteries I settled on are very similar, except they use a flat plate configuration instead of spiral which allows a greater capacity in the same physical size. My batteries are only slightly larger, but have 73AH compared to the 55AH of an optima. Very similar discharge/charge characteristics though, with greater expected life cycles and a superior warranty too, all for about the same price. I am very happy with my purchase.

 

They do look like normal batteries though, not nearly as futuristic in appearance as the "6-pack" design in my mind. I'd like to experiment with orbitals but I couldn't find anyone to sell me any? My next project will be higher voltage, something like 240v of orbitals would be perfect.

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Just looked at the wiring a bit closer. Some of those positive terminals are very close to the steel retaining bars... might want to insult them considering that if they touch you have about 700lbs of batteries to blow. Heh.

 

Yeah, I don't like that either. I have already modified their placement a little bit, moved them closer to the middle, in order to minimize that risk. They are clamped down with several hundred pounds of force, as much as I was comfortable wouldn't crack the battery cases. I'm in the process of installing rubber strips between the clamp bars and the batteries which will compress, spread the force out, and hopefully ensure that the bolts do not loosen under vibration. Still, I think I would like further protection against this potentially catastrophic occurrence. My list of options:

 

Weld cross pieces to lock the bars in alignment with one another, so even if one bolt should loosen there is no chance of the bar flopping around and coming in contact with a terminal

 

Weld the bolts that hold them underneath the batteries perpendicular to the brace so that the threaded rod holding them resists movement in either direction

 

Insulate the bars in some way (they are already slated to receive several coatings of POR-15, a rust inhibitor which is also non-conductive). Aesthetics are important and I can't think of any insulation which wont be ugly.

 

Insulate the terminals so that even if the bars did come loose and make contact with a terminal there would be a layer of insulation.

 

A dead short across multiple batteries would be very, very, very bad. They are rated to have a short circuit current of 3,500 amps. Pretty much enough to vaporize anything that gets in the way. I'd rather now find out what that looks like.

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I would just shroud all the positive terminals using that squareish shaped rubber cover that is on many car positive cable hookups.

 

This is all I could find on a quick search of Google:

 

http://www.solarseller.com/battery_terminal_cable_lug_covers_and_protectors.htm

 

I would go ahead and actually insulate the bars on second thought as well... Someone must sell a spray on insulator. Reason being... if water were to spill onto the tops of the batteries, which shouldn't, but could happen. That would be an issue.

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I would just shroud all the positive terminals using that squareish shaped rubber cover that is on many car positive cable hookups.

 

This is all I could find on a quick search of Google:

 

http://www.solarseller.com/battery_terminal_cable_lug_covers_and_protectors.htm

 

I would go ahead and actually insulate the bars on second thought as well... Someone must sell a spray on insulator. Reason being... if water were to spill onto the tops of the batteries, which shouldn't, but could happen. That would be an issue.

 

Not too worried about water, it wouldn't cause too many problems as it is not terribly conductive normally. Now, if salt water were to be dumped on the batteries that could be bad, but in that case each battery would short against itself and the exposed metal wouldn't pose any additional hazard.

 

I do think you're right through, those terminal boots are the best solution. I am placing an order for 13 reds and 13 blacks as we speak. (While I only have 12 batteries at the moment my controller supports up to 13, so its just a matter of time before I need that extra anyhow, who could resist ~8% more power?)

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who could resist ~8% more power?)

 

No one on this forum!

 

Ha.

 

I think a nifty idea might be to have a "cruising" battery pack and have those be high capacity but low discharge batteries. Then have a set of packs for "WOT" where they can discharge quick and give you some speed. Might have interesting results.

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believe it or not i seen one of those today while at sherwood mall. It was green though.

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The problem with those electric cars are that they ALL look like s**t

 

Yeah, I'm not a big fan of the xebra. Making slow, underpowered cars that just look like a novelty to most people does the image of electric cars a huge disservice in the long run. But I guess cheap transportation isn't a bad thing, and the more choices there are the better, even if I'd never be caught dead in one myself.

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This past week I just saw a show on TLC called Mr Electric Gadget or Dr Electric Gadget.

 

He has a shop out in CA and does electric cars. That show was about doing a 1967 Camaro for some rock/alternative band singer. It was pretty cool but the best part was when they sent it to the paint/body shop the guy had 2 S30s in there getting restored.

 

This Camaro smoked the tires pretty impressively during the final ride sequence.

 

Tom

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