jmead
-
Posts
169 -
Joined
-
Last visited
Content Type
Profiles
Forums
Blogs
Events
Gallery
Downloads
Store
Posts posted by jmead
-
-
And would solar panels be enought to have such a generator going ? Or a diesel generator that you configure to work with fryer oil .
20,000 watts would require about 2000 square feet of solar panels, in bright sun. I think the most you could reasonably fit on a datsun would be around 40 sq ft.
You could achieve that output with a diesel, but it would have to be about twice the size of the one I'm using.
If I were building the car for sustained highway travel (at higher speeds) I'd probably go with a 3cyl metro engine. They put out about 50hp peak, so it would be comfortable running at a sustained 15-20kw. At this point there really isn't any advantage to electric though. Your taking fuel (chemical energy), converting it into rotary motion (mechanical energy), into electricity (electrical energy), and then using it to propel the car (mechanical energy). An electric really excels at city driving where your speed is always changing, lots of sitting motionless, quick stops followed by quick accelerations etc.
Up to a couple hundred miles you may see some benefit because a percentage of the energy is still coming from the batteries instead of fuel, but you also have to consider the penalty of the increased weight and the energy conversion losses.
-
In theorie what would it need to be forever going ? meaning no charging ever except when you have the time to plug it ?
You just need a generator with an output sufficient to maintain whatever speed you want. For long distance highway travel I think about 20kw would be just right, which would require something like 30-40hp.
-
Did anyone else see the interesting Electric Powered 280 Z at MSA?
It was built by a shop called "Operation Z", which is located in Northridge, Ca. It had a 9" motor with 144 volts but the batteries were wet cell to keep the cost down. It had a 5 speed trans and they turned the motor on for me and ran it. There must have been a clutch to do that.
I liked it except it was too quiet.
Can you turbo an electric motor?
My motor has a turbo
-
Hate to sound like a kid but "do you have any more Vids" im a sucker for stuff like this
I'm working on it. I'm finishing up painting all the fresh steel under the hood, re-wiring for the voltage upgrade, upgrading the whimpy 400A fuse to a 800A unit, and replacing the controller with a unit that gives me control over current limiting, throttle ramp, etc. Plus it might actually be legal to drive on the road after this afternoon! But that also means I'll only have 10 days to finish the rear brake upgrade, headlights, horn, and turn signal upgrade before I need to get it inspected. Long story short - More vids in a few days.
I will be sure to record the first actual drive, and it would be priceless to capture the look on the guys face when he pops the hood to inspect it!
-
I now have protective boots around all the battery terminals. Bad things are much less likely to happen now. I will be getting my controller back in a few days (now with user adjustable current limit, throttle ramp rate). By that time I hope to finish the POR-15 treatment of all exposed steel, additional bracing/bracket for 13th battery, main contactor installation along with mid-pack 800A fuse, DC/DC converter installed and running 12v loads with a small battery to provide pull in for the main contactor to energize the other systems. I will then re-assemble the battery pack and hopefully take it to the strip. Then I shift my focus the charging/balancing stuff and the APU in the back.
-
Up till now I have had little know how about EVs and the build requirements. This thread has brought total light to the subject! Thank you very much!!!
You must have been pumped when you drove the Z out of the garage! Congrats!
When you are all done...if you are ever done making improvements...Id would love to see a build sheet...a summary of parts and aprrox cost.
And I too would like to know more about the all important charge time!
I'll tell you a secret, the video of the "maiden voyage" isn't the actual first time it moved. When I realized I was close to that point I stayed up all night working on it. It was around 5am that I finished and I just had to see it move before I went to sleep. The video wasn't until the next morning when the camera woman was with me.
I will post the log of all my expenses on the blog when I'm pretty sure its complete. Right now its around $6.5k.
-
I see that the batteries you use are rated at 930CCA. What is the general ambient temperature in your climate that you operate your car in and what is the CA rating of that battery at that temp?
The reason I ask is because I am seriously looking at buying a 240z to restore for a driver. I restore cars and have the means to do anything to a car.
And while I have looked extensively into E-85 and will probably convert all of my internal combustion engines over to run higher compression and run a richer mixture to run the moonshine if I want to, I would absolutely LOVE to have an electric Z if I can do it practically.
My only problem is that we see below freezing temperatures here in Denver, which might kill the deal for me, depending on if the pack can withstand CCA efficiently enough to do at least a 30 mile trip between charges.
Also, do you have a closed circuit to run your accessories, lights, signals, wiper motor, etc, or are you running them on the same pack? I would also assume that the car has no heater, but if it's going to be D.O.T. approved, you need lights and wipers. I would imagine that a car like this would benefit immensely from LED lighting all the way around.
I think I could come up with a cheap propane heater for the winter here, but is there a way to use the heat from the motor? Maybe with the water cooling you mentioned?
I understand that any other draw on the batteries takes it's toll on range and efficiency. I'm just trying to mow all of this over in my mind to see if it's practical for me to build. The main focus would be for a driver, with moderate performance attributes, similar to the torque ratings you have.
If I were to build something that could get a 50 mile range in cold weather between charges, what type of battery would you suggest?
In NY the temperature swings around alot, from 100s in the summer (sometimes) to below freezing in the winter. That is one reason I chose these particular batteries, unlike "flooded" lead acid batteries which actually have liquid inside of them that can freeze when discharged, the AGM have something more like a gel. They are much more cold tolerant than a normal EV battery.
There are several tricks the EV folks have come up with to deal with cold conditions that you don't see on my conversion. Its pretty common to insulate the batteries with a layer of styrofoam insulation. The batteries have alot of mass, and therefore thermal mass, so as long as they start at a good temperature they will stay that temperature for a pretty long time. Long enough to do what you need to do and get it back in the garage. Another system (often used in conjunction with insulation) is to add small flexible self-adhesive sheet heaters to the pack. Sometimes this lines the bottom of the battery box, or sometimes stuck to each individual battery. A small thermostat keeps the batteries warm while it is plugged in so they are ready to go. As far as I know these aren't used while driving.
Even batteries that don't like the cold will still work, they just don't give you as much usable energy when warm. In fact, EV drag racers use this same principal and heat their batteries up even more on purpose (through lots of high amp discharges and quick charges) to get them to produce even more current for their short runs. If you need 30 miles of range when cold all you need to do is plan things out so that you'll have 50 miles of range when warm.
I am running all the accessories from the traction pack. I am in the process of installing a device called a DC/DC converter which takes the high voltage from the pack and turns it into the 12v needed. Compared to the huge amount of power needed to move the car (something like 100A at 156v on the highway) the draw of the headlights and such (maybe 2A from the pack) probably wont make a big difference. I decided it was better to add another battery to the big pack and use some of the total energy for the accessories than to have a battery just for them that will end up being barely discharged most of the time (dead weight).
I'm planning on installing an electric heater. People often hack apart those 3000 watt space heaters and install the heating elements where the heater core used to be. They work equally well on AC or DC.
-
sorry for the dumb question, but did you explain how it does get charged, or how long it takes to recharge using household energy sources?
I've skirted around the issue because I'm not totally done with the charging setup. These batteries are capable of being charged incredibly quickly, even in less than 1/2 an hour if you could supply enough juice. It all comes down to how much energy you can safely draw from your source and controlling it while it is being fed to the pack. I am planning on charging at home from a 240vac 30amp circuit. Assuming I can get 25 amps of charge current actually making it into the batteries, my charge time for the 75 amp-hour pack will be around 3 hours. If I were charging from a 120vac 15amp circuit it might be closer to 5 or 6. This is for a 100% drained pack, if all you've done is drive it down to the grocery store you could probably replace that energy in just 15 minutes.
Perhaps in the future I could upgrade to a 50 amp circuit and cut it down to a little over an hour.
The electricity is fed into the whole string of batteries at first. But each one is slightly different and one will finish charging before the rest. I'm designing a system so that a battery monitor sees when this happens, shuts of bulk charging and then goes around with a smaller computer controller charger and tops each one up until they are all exactly 100% full. It isn't necessary to let this happen before you can drive it, its more of a background system to keep the batteries all happy and balanced without any work on my part.
-
Does your controller do regen? If you don't have a clutch maybe you could use the old clutch leaver as a regen leaver?
No regen. It'd be nice but there is no 500+ amp controller available with regen, and they have a habit of dying an early death I've heard.
-
Voltage upgrade. I've purchased a 13th battery, making for a total of 156v now. This takes me from 144,000 watts to 156,000 watts, or 166hp mechanical (based on 80% efficiency). Total pack capacity is 11,700 watt-hours now from 10,800.
I am in the process of welding in the new battery steel, painting the new steel surfaces with POR-15 to prevent them from ever rusting. I'm also installing the DC/DC converter to run all the 12v appliances from the 156v traction string.
And I've found a drag strip within 7 miles of my house, perfect! Cruise to the strip, make a few blasts down the track, cruise home without dropping below 50% charge.
-
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.
-
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?)
-
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.
-
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.
-
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.
-
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.
-
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.
-
so you would need 3/4 of a gallon of gas to run the generator for enouph time to fully charge your batteries.
and once the batteries are charged you can drive 65 miles on them.
so you'r basically doing 65 miles with 3/4 of a gallon of gas?
no need to charge the batteries with the generator, you could simply drive the car using the electricity being produced by the generator. At 10kw it'd only be enough to travel maybe 50mph or so on level ground. If you were traveling faster than this, say you were going 70 and consuming 17kw of electricity, the first 10 would be provided by the gen and extra 7kw would be coming from the batteries.
-
Earlier you were talking about using a generator to charge the batteries for long distance driving. How much gas do you think the generator would use in order to charge the batteries in your car (when the car is just sitting)?
And then let’s say you’re just driving and you run out of battery power and you decide to turn on the generator. How much gas would it be using as you drive down the freeway? I know these are questions that you won’t have a sure answer but I would just like to know your educated guess.
Keep up the good work though. This is VERY interesting!!!!!!!
Plugging some quick numbers into the incredibly handy EV Calculator I see that the a 10kw output should be capable of sustaining a cruising speed of 65mph on perfectly level ground. In this scenario the batteries will be used only for additional load (incline, headwind, increased speed), and they will receive the surplus output when load decreases (downhill slopes, tailwind, decreased speed).
If I then extrapolate this with data available on diesel generator fuel consumption, which appears to be 210-240 grams fuel per kWh. Therefore 1 hour at 10kw will consume 2400 grams = 5.3lbs of diesel fuel. Diesel weighs about 7.2lbs per gallon, so this equates to .75 gallons of fuel to achieve 65 miles.
Good enough for me...
-
Ok, so who's gonna be the first to put twin 11 inch transwarp motors in their Z?....
Almost sounds as yummy as twin VG30E motors... Range won't be as good with the electric though.
Each is capable of 600 ft lbs! Combined with a 2000 Amp zilla EHV (extra high voltage - 348v) you'd have 1200 ft lbs of go.
Thats alotta go
-
Since you're only using 1st and 2nd your cruise transmission ratio is 2.197.
Going direct drive you'd need at least a 7.xx+ rear diff to get close to the final ratio you currently have with 2nd gear.
I like the idea of direct drive, but it seems it might be a bit too much stress long term on the motor correct? I also just love the idea of having the entire motor in the trans tunnel. Open up the hood - "What motor?". Weight placement would be pretty good.
I may need to go to 3rd for highway use, I haven't taken it up that far yet (not registered, working on it), so I don't really know. Ideally your rpms are around 3-4k at cruise, this is where the motor is most efficient. Direct drive is more stress, but it depends on the setup. If you've already got way more motor than you need, something like twin motors or an 11", that extra few hundred amps starting out in 3rd (close to what a direct drive would be) doesn't make a big difference. But with the 9" I've got it would be pushing things. Maybe because it is such a light car I'd be OK, but since I live in a very hilly area I'd be afraid of frying my motor up a long hill. Now I can just watch my amps and drop it down a gear (higher revs for same total power = less amps) if they are too high for too long.
The transmission tunnel is the perfect location. Twin motors direct drive to the diff and located right between the seats would be the perfect setup in my mind. You could then just place batteries wherever you wanted to get the weight balance perfect and the center of gravity as low as possible. It'd annihilate anything on the road.
-
Did you ever consider using something like a FWD tranny and mounting the motor in the back? That way you would have more room under the hood to mount the batteries lower and farther back.
That would be ideal. I really contemplated turning the differential around so it was facing the rear of the car and directly mounting the motor to it. It seemed like too much of an engineering hassle though. Mounting the diff would be difficult, and a FWD tranny would require some major hacking to get in the back of a Z.
It would also be possible to get a "transwarp" motor which just a normal motor with a slip yoke instead of the shaft. This allows you to connect straight to the driveshaft and mount the motor in place of the transmission. The engine bay would be totally free for batteries this way too.
-
wouldnt a automatic or even an CVT transmission work on an engine like that i know youd need a tranny cooler and a T converter but is it doable ?
A few EVs have been made with automatics, but its not a popular choice. An auto needs to idle to keep the fluid pressure up, and the fact that motor's don't idle is a big benefit (in my mind), but there is no reason they can't. Also total transmission efficiency is lower, and you barely ever need to shift anyhow....
And CVTs are cool, but inefficient. I did see plans for an EV that used a CVT instead of the expensive (and most likely components to break) motor controller. Instead of the controller regulating voltage/amperage, you just applied full voltage to the motor and used the pedal connected to the CVT to control speed (and therefore amps).
I don't know if that made any sense, but I think that is a very cool idea. I'd like to build something using that concept (maybe a dune buggy) because it would cost half as much without the controller, but I need to find a CVT that has a manual control cable first.
-
The guy that is or will be helping me, has been looking into using Li/ion batteries in the AA or AAA size, which we will then place into our own cases, replaceable as modules.
I'm likely going to start with conventional batteries to get it going and then switch out later, once the initial cost of conversion is dealt with.
As fas a wh/lb goes lithium are unbeatable, I attempted to buy several thousand 18650 cells not that long ago to do the same thing, but the deal fell through. The amount of man hours needed to build a pack of sufficient size is huge, don't underestimate the amount of effort required. I'd definitely go lead acid at first. You'll get a few years to work the lithium angle, and prices are always coming down.
I'm more interested in the choice to use the tranny, especially without the clutch. I've held onto my clutch for now, because I figured it would be easier to drive with, especially while down shifting. I can drive no problem without using the clutch, but still need to work on my clutchless down shifting, I would imagine this would be more difficult (for me) than with a gas engine, since I'm used to the rate of decay or RPM on a gas engine, especially with a heavy flywheel, with just the coupler, the rate of decay should be higher, making that time to slip into the lower gear shorter.
I'd rather run without a clutch, since that's added weight that will eat power, on accel, but may help once your rolling along.
I don't have a flywheel, partially for that reason, more inertia coupled with the motor. I can't say how it effects shifting, but it does seem like it would take longer for the syncros to change match the motors speed.
I'm even considering doing away with the tranny, and going with a taller gear, to save weight, but I'm not sure how towing will be effected by this. Hmmm, removing 1st and 2nd gear, and leaving only the last 3 gears for towing accel and cruising may be an option.
Seems like the last 3 are even less important the first. It seems like you really only need 2 and 3, though 1st is nice to have for very steep grades/very slow speed.
Direct drive does sound interesting. I bet the ~5% parasitic loss difference would end up being more noticeable than the ~50lbs of weight difference, together they would probably be significant. But that gain in efficiency at cruise is offset by a loss at low speeds.
Electric 240z Project Pics
in Other Engines
Posted
Anything over 200 miles is beyond the capability of even cutting edge technology on battery power alone. With the affordable tech even 100 is near impossible, unless you design a car around the batteries (john wayland's truck "red beastie" can do 100 miles on lead acid I believe). I think the best bet for that range is a hybrid, similar to what I'm planning. You can't beat fuel for kw/lb.
A BMW wagon would be a very cool project. Lots of room for batteries, but with alot more style than the rusty ford wagon that seems to be so common.
Those LiFePO4 look very interesting, I had no idea they had made it to industrial use in forklifts and such yet. hopefully it won't be long before you can score them in junkyards and second hand with thousands of cycles remaining for a fraction of the cost new. It seems to me that LiFePO4 is the future, and we're on the verge of the transportation revolution because of it. They just need to crank up the production to millions of units and get the price down. I can't wait for the Lithium Z.