Advice needed for making of an EV/Hybrid

cobb

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I am thinking about getting my drivers license this fall/winter and was offered a car. I was offered a geo metrl xfi from my dad that needs a new engine. I thought I would see about making it an EV after a few conversations with email to darell a super terriffic super guy and Daniel the hybrid freak.

I see a few kits online, deluxe ones from evparts for 12 grand and cheap ones from 1999 http://www.e-volks.com/about.html2.html

I guess I should start with my use. For one, I want to go to work and back. 11 miles one way by the interstate. I see from the cheap kit the speed is limited base on bank configuration or max voltage, which also effects range. Faster you go, less miles you can travel as it takes more power to travel faster than slower. I want to travel 67 miles by highway i295 65mph speed limit to visit my folks. I know for sure a generator would be needed to supplement my needs, yet make it efficient.

Another concern is charging it. If my apartment complex wont help me, I would need to plug it in at work. That would limit my range on weekend, unless its a hybrid.

Another issue is heat. Do I need a functioning heater to pass inspection or does it just need to blow air? I can install an electric heater and a fan elsewise.

I am thinking about the cheaper kit with the PWM so I can regen charge. Use a bank of batteries for the speed limit I need to travel 8, or half that (2x4 in parallel) for city use but use two banks. Then switch it from parallel to serial for highway and after a few miles pull over and start the generator or after so many miles start it before I arrive at my destination. Guessing I could get electric start and make the switches accessible inside?

One concern was where to mount the generator and how to tell an efficient one, plus battery charging. My dad said a gas engine could not be mounted under the hood, it would need a remote tank in the back. A gravity fed system wont work and would need a pump, I think a big mess. Another is charging, I guess I would need 2 chargers. One for the grid and one for the generator.

Another concern is, how do you tell an efficient generator? I ran the numbers on the models in the northerntool catalog that listed tank size, run time on half load and total output divided by 2. I divided the tank size into run time and that by the wattage at half load. item #165912-2601 came to a .0001516 the lowest number of all the generators. The diesel one item#165939-2601 was second and the little 2000 watt honda red enclosed generator came in third.

So, the idea is to get that said kit with pwm, mount 8 batteries, 2 banks of 4 in parallel or serial model for 8. Then the generator under the hood with electric start (I hope) and to crank it on my way to or near by when needed to extend my range for my weekend highway driving. Daily driving, just plug it in at work to charge it. I was going to get the extended fuel tank, 6 gallons i think for the generator and fill it as needed. I would only use the generator to extend my range or emergency, I would charge off the grid elsewise. Just got to find a 1200 watt charger to use onboard and maybe a 220/110 charger for the grid. THe shop actually has 440 outlets too.

Thanks for any advice/help, etc.
 

gadget_lover

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Wow! That's quite a project that you are taking on. I envy your decision to create a series hybrid.

I'm fairly sure that a working heater is not required in any car in any state. It's great to have, but not strictly necessary. Don't underestimate the abount of heat the motor and controller will create. That heat might be ducted into the cabin.

When it comes to cheap VS expensive, make sure you get to talk to folks that have used the system. There is generally a reason that people can sell the more expensive versions.

If installing a fuel pump seems like a big deal, the installation of a 15kw motor and asocciated batteries might also be too much. Get a copy of the installation instructions before buying a kit. Beware of any claims that you can be "on the raod in hours". It will take hours just to make the brakets for all the batteries.

The hybrid idea is really cool. Picking the right size is a problem. If you have the battery capacity to travel 30 milesat 60MPH with a 15kw load, then extending that to 60 miles means that your generator has to provide 15KW for 30 minutes, or 7.5 KW for the whole 60 minutes. A 7.5 KW unit is pretty big. It will drink some gas and will need cooling as well as an exhaust system. Even so, you can get a 10KW unit for around $1000. Some folks have gotten past the problem of the onboard generator by putting the generator on a tiny 3 foot by 4 foot trailer and towing it behind on long trips.

To get unlimited range you would need a generator that will steadily produce the maximum power required by your motor (including losses). Figure a 15KW or bigger for unlimited range.

The controller and the motor are really the keys to efficiency. The cheapest will not always give you the most distance per watt. There are other things to consider (that I used to know 25 years ago) about which are smooth and which will tend to lurch. Some will allow you to use a single gear and others will require a transmission.

Regenerative braking requires a lot of careful design, since the degree of braking will depend on how much juice can be pumped into the batteries. Too much, too fast and the batteries break down prematurely. It's quite doable, but the controller has to be properly designed and matched to the battery bank.

E-volks.com says they have turnkey Geos on their site. That should mean ready to drive. Maybe they would take yours as a trade-in?

Daniel
 

cobb

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THanks. I never considered towing the generator, however mounting it on a shelf behind the car is an idea. I maybe able to mount it low enough to use the existing gas tank. Not sure how to hook a 5hp motor to a cars 8 gallon tank. Bet some adapters would be needed and a cut off so bouncing around it wont waste gas when not needed. My grand idea was to use the stock gas tank in the generator to leave it running a few hours. Rather on the road or when I need to juice up, but no outlet is near. Then when it ran out 2 hours or so later, it stopped. I would use a simple switch in the gens tank to let me know its full and use a transfer pump to use the cars gas from the cars gas tank to top it off. The other idea was to remove the cars gas tank for more battery room and buy the optional 6 gallon tank for the generator and mount that under the hood.

Another idea was to use a 120 volt electrical system and use a bridge or rectifier on the generators output and use it for direct charging.

Another thing that wasnt addressed is the 12 volt power for the cars lights. Not sure if it has an air bag, but I do recall it having running lights, except when its in nutral. I think I saw a 96-12 volt converter somewhere.

I thought I would just buy a 12 volt accessory heater, kind of what i use on the old wheelchair. It had a 240 watt unit.

I guess the biggest hurdle is the generator. You think I will need a larger one and am not sure if larger is more efficient or if any are at full load, vs half load. The longest I willdrive is the 67 mile trip one way. Not a problem at all to pull over and shop at wally world or take an extended smoke break. :)

I hate to have something larger than the stock engine and tranny. I mean it has a 1 liter 3 cylinder motor. Also, I am lead to believe not many of the motors are that efficient. I think the OHV are and seems the OHC a bit more. Of course a diesel running biodiesel would be better, but not sure a they sell that or if i could make it.

I was thinking about the batteries too. May not be enough room for 8 batteries and a generator under the hood. I thought about putting 4 in the rear and 4 under the hood, but dont want to cause an imbalance with the voltage drop per length of cable used. I guess I could put 8 in the back. Its a 4 seater car, however the back seat was folded down and the two front were only used. I would just remove the back seat and get a box welded in to house all 8 batteries.

I think this kit requires you to drive as if it was gas. I see a few kits that require a 10 to 1 final drive ratio and suggest you leave your manual tranny in 2nd gear. Now that I think more about it, maybe I could just leave the batteries in series for 96 volts? I know amperage would measure load or efficiency, just trying to decided how I would need to drive it. Low or high revs? Low or high gear?

I would need to get a shop to help me. I could remove a lot of crap under the hood and loosen the engine. Depending on if the engine drops out or raises out I maybe able to remove it and install the electric motor. I would need to get the battery boxes welded in. I think a local metal shop exist where my folks live and a universal shop. Would also need some cable cut, crimped and lugs attached. Dont think the cheap kit comes with cable like the more expensive kit does.

Its something i want to seriously consider. I dont want to put too much money in it. I mean, whats a prius cost? 18 grand? The professtional kit was 12 grand. Then I would need labor and 12-10 group 24 batteries deep cycle.

Well, going to sleep on it.....
 

gadget_lover

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The need for a larger genny is based on your stated commute and the e-volks information. They list the motor as 15kw at 70 MPH in a Geo. That means your 65 mile trip is just about 15KWH. You said the stock setup would get you 30 miles at 65MPH. The generator would then have to provide the rest of the power, about 7.5khw. If the gen is running the whole time a 7.5kw gen will do the job, but the batteries will be drained when you get there.

About charging while you shop....
Lead acid batteries last longest when the charging is strictly controlled. You typically charge them at some fraction of the current that you can draw from them. This means that you could deplete your batteries in a 30 mile highway run and then spend 4 to 12 hours charging them again (depending on the battery construction and charger).


About generator size. There is a formula that tells you the number of KW that can be generated per HP of input power. A 10KW will typically have around a 15 HP motor. Physically, its pretty big. For an idea, look at http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=54648. The cradle is about 3x3x4 foot. 250 LBS. To use your 2kw, 5HP example, you'd have to park for 7.5 hours to fully recharge a 15kwh battery pack.

You can usually connect your 12 volt accessories to a single battery in the string. I don't know if there are technical reasons to avoid doing that.

Yes, a Prius (used) is only 14 to 18K dollars. Occasionally you see wrecked and rebuilt (salvaged) Prius on E-bay for fair prices.

If you are careful, and get real prices for everything, your Geo-EV may be quite a fun project.

Daniel
 

cobb

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Interesting..... I know from use of electric wheelchairs and scooters it takes little power to go from dead to driving, although still low is what the power meter reads and soon as you roll it starts to walk over to low again.

Man, sounds like I need three battery chargers? One for the grid, one for half power and one for dump mode or 15kilowatts. THats likely a bridge hooked tothe output.

I am still unclear about the efficiency of the generators. Are they more efficient at half or full load? Would it matter that its gas or diesel in that case? I lean diesel, however the generators i crunched the numbers on showed it was second place to said honda generator in my first post with the OHC engine.

Now the trip wont be 65mph for 67 miles or so. THe fastest I would need to go is 65 on part of my trip that crosses i295. I could do it on 64 or 95, however most folks run 95mph there. I think the fasted range is 60mph Then I would cross 460 and the speed limit there ranges from 55-35mph . Lastly some backroads before I arrive home. I may pull over and take a break as its an hour and half ride.

I dont know, the less I see how usable an ev or serial hybrid is, I may just see about fixing, rebuilding, buying new, rebuild or used motor for the car. At least then I would have my AC. This 90 degree heat, I sweat, a lot. I have some friends who can make a t shirt crusty in 6 weeks. I can do it in a few hours. I drunk 176 ounces of fluids Saturday at the field day of the past show the 8 hours I was out there and only had to urinate once. I sweated the rest out. I drink a lot and sweat a lot on a regular bases standing on street corners and on the buses that have the ac on with winders open, heater on or the ac is off cause its broke. THose fiber glass shells heat up very fast and stay hot.

My boss gave me a ride home and man, his ac will freeze you out of his car, some chevy suv thing. I loved that. I rode with my dad Sunday to visit my mom in the hospital. Not only does his only 81 mercedes 240 D have a marginal AC, but so had my moms suzuki suv hes been driving the past year. My dad manages to manage his ac usage so it fails and repairing it makes little to no difference. Of course he seldoms uses it. My uncle left it on full blast year round and it always worked for him, never needed it serviced far as I can remember.

Yup, driving the geo with its ac in operation while it gets 50 or so mpg sounds great. Not like its a gas hogg to start with.

Just seems this maybe more difficult or costly than I thought.
 

gadget_lover

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Yes, it's always more difficult and more costly. I think that's a law of nature. :)

The generator efficiency depends on the specific design. To reach peak efficiency the electrical load must match the generator, and the generator muct match the motor. The motor speed must be just right for the motor AND the generator to reach max efficiency.

The typical gasoline driven car is designed to be a multi enviroment, multi task vehicle. It is vastly overpowered for use in the city, and it's much too big for use by a single person for local transport.

I'd suggest you consider using the Geo-EV for your local trips and either buy, borrow, or rent a second car for your twice a month trip to your parents. Or car pool. Or invite them to your place. You'd be surprised how many ways you can make it work.

Because you are looking to do the project on the cheap, you will find there are limits to what you can expect. If you were spending a bit more, you could reasonably have a 100 mile round trip range with a standard BEV. You might sacrifice some passenger room, but that's not unusual in an EV convesrion.

This quote from:
http://www.eere.energy.gov/vehiclesandfuels/avta/light_duty/fsev/fsev_history.shtml

The Geo Metro, converted by Solectria Corp., is an electric-powered 4-passenger sedan powered by an alternating current motor and lead-acid batteries. It has a range of 50 miles, and it can be recharged in less than 8 hours. During the 1994 American Tour de Sol from New York City to Philadelphia, a 1994 Solectria Geo Metro cruised over 200 miles on a single charge using Ovonic nickel metal hydride batteries.

That gives you a feel for what you can expect from a small car like that. If you decide to jump into a conversion, I woudl think that learning to weld would be a big help, since it would allow you to create custom battery holders so you can wedge teh batteries in where you want them.


Daniel
 

HarryN

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I have thought about building an EV a number of times, but taking on the complexities of a hybrid on a limited budget is a bit daunting.

The key to success at this stage is - keep it simple. I suggest that if you want to take advantage of the EV aspect, focus on that, and just plan on using your Dad's car when you really need a longer distance vehicle. Skip the generator, etc unless you want to just drag along a standalone one which drops in your trunk and you stop at a rest stop periodically to charge up. (maybe a 3 - 5 hp one for emergency use)

This project would be a lot easier if you were using a rear wheel drive car, but if not, consider trying to remove un needed components, such as the transmission and run the motor direct drive if you can.

I would use a larger motor - maybe closer to 50 KW - 15 kw might maintain 70 mph, but it will take forever to get there - really an usafe situation. It will not use more power than the smaller motor, but will run at a cooler temperature.

Your power losses will be less by running at the highest possible voltage from your battery array, but it might be worthwhile to run it the same way that an RV does - in parallel. That way, if one "set" of batteries goes dead, you have the other to draw from. Try to run using a DC voltage that is used in an industrial application - this will make it easier to obtain parts.

Strip out the gas tank and use the space for batteries, etc. You will need it.

It might be worth your time to consider a hydraulic motor system attached to your electric motor to actually carry the torque to the wheels. Hydraulic motors are very compact and have a lot of torque. They often tend to be less sensitive to the shock than an electric motor.
 
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cobb

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My folks live 67 miles from me one way. I may see about buying his 240d mercedes instead. It runs, diesel powered and has a marginal workng AC system. Its a large, light weight made, marginal heavy car. No plans to make it an EV or hybrid. I rather gut it and make it a sleeper. I can just picture a blower sticking out the hood of the car.

I think the geo is not the right platform for what I want to do. Sounds like i need a pickup truck. This way I would have the capacity to carry a larger generator and banks of batteries for range and cargo area. They make kits for s10 trucks. I could have two banks of 12 cells in parallel for doubled range then a 15 kilowatt generator for more or when the power fails in a truck.

The kit they sell looks great for a old vw bug and maybe a city geo. I would be fine city wise, but I would have problems with my weekend excursions.

Another option is to hit the boss up for a company truck. He issues them, just have to pay for gas. I really enjoy working and what little driving I have done with the f750 skunk lift truck. Its easy to get in and out of, nice seats, good visability and a cold AC system.

Thanks for the help. I think even Darell has a gas powered car for his trips his EV wont do. I had joined a yahoo ev group, but it was all wanna be members and one who just bashed Bush constantly. I posted my question. Infact a few times with different variations as many posts never made it.
 
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