# Real World Practicality of an EV Conversion



## crunching_numbers (Oct 25, 2012)

Hi everyone, I'm a noob to the site and electric vehicles in general, so I thought I'd seek out some advice. I've read the wiki, browsed through the EValbum, did some quick calculating and I'm left wondering, how is an EV conversion a practical, economical alternative to gasoline? Perhaps my numbers are wrong, but from my perspective it doesn't appear that I can save any money converting to electric.

My observations so far are that most EV's seem to fall into one of two categories: extremely minimal range or extremely high cost to convert. Neither is practical for me. I must admit, when I started looking at electric as an alternative to gasoline the $0.70/gallon equivalency of electricity looked pretty hard to go wrong by. (I reached that number by using the EPA equivalent of 33.7 kWh = 115,000 Btu = 1 gallon gasoline multiplied by my current electric rate of $0.0938/kWh and dividing by 4.5 to factor in the difference between a 20% efficient ICE vs a 90% efficient AC motor.) However, it seems the "tank" is the limiting factor in an electric car, as opposed to the fuel. Perhaps I am just looking at the wrong batteries? I will delve into my calculations below, please tell me if I'm way off on something or if my conclusion that electric cars cost just as much to drive as a gasoline car is accurate.

Assumptions:


The best car to convert is a light car with a low drag coefficient and frontal area (generally speaking, this is also probably a car that gets good gas mileage in original form).
LiFePo batteries are superior to Lead-Acid batteries in capacity to weight ratio, efficiency, and lifetime cycles vs cost.
AC motors are more efficient than DC motors.
Most EV's consume on average 300-350 watt hours per mile (I reached this assumption after browsing the EV album to find nearly every car or light truck with a listed wh/mile rating falling between 300-350).
 
My Needs:


>50 miles of range throughout the lifetime of the battery pack. My commute is 45 miles round trip and I would like a little breathing room if I want to run the the grocery store or something before/after work.
Capable of reaching 65-70mph in a reasonable amount of time (<12 seconds) and reliably maintaining that speed (approximately 1/3 of my 35 minute commute is 65mph).
Capable of operating reliably between -20 and 110 degrees Fahrenheit and maintaining range. (I live in Wisconsin, I realize I will most likely need a heating/cooling system for the battery pack.)
Offer a low enough cost per mile vs gasoline to pay for the conversion within a reasonable amount of time (5 years?)
 
So here is my theoretical comparison. Vehicle will be a 99 Dodge Neon for comparison purposes.



Approximate Curb Weight = 2450lbs
Drag Coefficient = 0.33
Manual Transmission, approximately 3000rpm @ 70mph in 5th.
33 mpg average on gasoline as a baseline (real world average, this is my car
11,250 per year (Calculated as 45 mile round trip, 5 days/week, 50 weeks/year)
Cost to drive $1,734.09/year (calculated at 4.50/gallon with $200 added for engine maintenance, both estimates are higher than current costs)
 
Proposed EV Conversion:


AC motor & controller
DC to DC Converter
BMS & Charger
96 volt LiFePo Battery Pack consisting of two series of 30 3.2 volt, 100Ah CALB cells
Additional small parts required for the conversion and any custom fabrication
 
I chose the battery pack using the calculations outlined in "Sizing your Battery Pack" on the Wiki. I chose 96 volts on a whim, mainly because 30 is a nice round number (30x3.2volts=96volts), I've seen other cars in the EV album using this voltage, it falls in the voltage range of some of the AC motors I'm looking at, and, quite frankly, I could not afford any more batteries (even this is a stretch). So 96 volts multiplied by 200 Ah (since I'd be using two parallel series of 100 Ah cells) equals 19,200 Wh, or 19.2 kWh. I then multiplied that value by 0.8 for an 80% DOD for 15.36 kWh. I then divided by 1.05 to account for the Peukert effect on LiFePo batteries for approximately 14.63 kWh of usable energy (rounded up slightly). I also multiplied by 1.1 to assume 10% energy recapture using the AC motors regenerative braking. This left me with around 16.09 kWh or 16,090 Wh, divided by an average consumption of 300Wh/mile equals a 53 1/2 mile range. Whew. Follow me so far?

Calculating the cost to drive:
I used 300Wh/mile and multiplied by 11,250 miles, then divided by 1000 to convert to kWh and multiplied by 0.9 to assume 10% energy savings using regenerative braking with the AC motor (which I've read is a high estimate). I came up with 3037.5 kWh for my yearly consumption, which I multiplied by my current rate of $0.0938 for a yearly cost of $284.92 for the electricity. This is assuming the 300Wh/mile average is calculated at the outlet, not at the motor (in which case it would cost more due to losses between the outlet and the motor).
The LiFePo battery pack is supposed to last for 2,000 80% DOD cycles with a proper BMS installed. I would commute 250 times per year based on our 11,250 mile benchmark, so the battery pack should last 8 years (2,000 divided by 250). The cheapest LiFePo CALB cells I found cost $1.35/Ah, or $135 for one 100Ah cell. This puts the total cost of the battery pack at $8,100.00, which I divided by by 8 years for a cost of $1012.50 per year. So the cost of the "fuel" and the "tank" for and EV conversion at our benchmark miles per year is $1297.42.


I just want to say, thank you very much if you're still with me! So, according to my calculations I would only save $436.67 per year with gas at $4.50/gallon (which it isn't here yet, closer to $3.60/gal for premium right now) commuting with an EV as opposed to the original gasoline powered car. This does not factor in any other maintenance to the electric system. I haven't even begun to price out the rest of the parts needed for the conversion, but I would say a conservative estimate for an AC motor, controller, BMS, charger, DC-DC converter, miscellaneous parts, custom fabrication, custom heating/cooling system for the battery pack, and additional parts required if I want power brakes, power steering, heat, or air conditioning, to be in the neighbor hood of $6,000 or more. And we still haven't accounted for the hundreds of hours to complete the conversion. At that rate, I would need to drive the EV for NEARLY 14 YEARS before I break even on my investment, giving up the convenience of a gasoline powered vehicle for every one of them.


My conclusion: EV conversions at current fuel prices, with current EV technology and prices = COMPLETELY IMPRACTICAL.


Please do correct me if I have made an error anywhere along the way, as I would love to believe this technology is actually economical and practical. Unfortunately the numbers say the exact opposite... YMMV.


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## Joey (Oct 12, 2007)

It is pretty tough to come out ahead when you are comparing a mass produced gasoline car (with all the economies of scale) to a one-off custom electric conversion. You can tip the scale by finding used parts, and building some of the open source components yourself. 

The conclusion is, at this time, most people are going electric for more than just the economic payback. When I look around at the cars around me on the road, very few are the most cost effective solution available for getting from point A to point B. Other factors are at play. I like that I'm going to by buying less oil from countries that are less than friendly. I like the silent ride and low end torque of an electric drive. Eventually I can produce the power myself, if I put enough solar on my roof. I like projects and working in the garage. My car will break even after 280,000 miles, but the payoff will be when I take my first ride in a car that I converted myself.

It seems like you have done a fair bit of research. I don't want to discourage anyone, but if you only want economic payback, a conversion might not be the right solution until battery prices come down or fuel prices go way up.


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## dragonsgate (May 19, 2012)

I have been driving my EV for over twelve years now and there have been times I have wished it was an ICE again. Usually when I am having a good time driving it and the battery gage is telling me I should head home. I do not have the fastest EV ever built but it gets down the road pretty good. I did not convert for the environment or because of oil dependence and gas prices. Those reasons are just perks to me. I have always liked to work on and modify cars and motorcycles so when I first read about electric cars in the late 1970’s I always wanted to build one. In 1999 I did and have enjoyed it very much ever since. Even though I had no noble reasons for building an electric it has been fun watching the gas prices as I drive by the filling stations. You should not build an EV with the idea it will pay for it’s self. The only sure thing is the immediate savings on gas. What little I have saved over the years by having a home built EV I have dumped right back into the car plus some in body work, paint and other modifications. Do all the figuring and calculations you want because it can be fun trying to figure out the what ifs and it can also help in deciding what and how to build. In my opinion the real reason to build an electric car is because you want to.


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## mora (Nov 11, 2009)

Your calculations seem good to me. It seems its just not wise to convert a car that gets high mpg to full electric if it is about money savings. 

Your gas price is pretty low there, 3.50$/gallon is about 0.92$/litre. Now your proposed 4.50$/gallon would be 1.19$/litre. Gas goes for 1.75eur/litre here. 1.75eur is roughly 2.27$. When one gallon is 3.7854 litres we have gas price of 8.59$/gallon. It is pretty common and seems to rise all the time. "Premium" fuel goes for even more.

Now that makes a difference when calculating financial benefits. Still my gf's Peugeot 206 gets close to 50mpg and I think it is not a good idea to convert it to electric even at these prices.


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## glaurung (Nov 11, 2009)

Hi Crunchn
I would suggest you do the numbers again with some upscale vehicle. Try with V12 MB or Beamer. You will find out that you pay your conversion a lot faster if you do not convert a smallest car you can find.Remember that 4x4 vehicles make fast paypack too. Or 4x4 with big V8.
These beasts use 10 000 euros worth gas a year. That will get you a lot of batteries.
Regards, Harri, Leguan(ex V12), and Rangie(ex V8)


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## muffildy (Oct 11, 2011)

the most practical from an economic standpoint is to convert a lightweight aerodynamic car that currently uses a large inefficient gasoline engine to use a small efficient diesel engine and use an electric system to boost acceleration.


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## TEV (Nov 25, 2011)

You are right, but you forgot to calculate the " EV Grin "


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## EVEngineeer (Apr 11, 2012)

Gas=loud and lots of noise pollution, lots of bad emissions, expensive gas prices, lots of maintenance.

Electric=less noise, zero emissions, cheap to recharge (free or near free with solar or wind power), little maintenance (Electric does not require periodic tune-ups, filter replacements, SMOG certification, oil changes, weekly dirty and hazardous gas fill ups.). TIME IS MONEY, with less things to worry about with an EV, creates more time for you to spend on more important things. 

http://www.diyelectriccar.com/forums/showthread.php?t=5095 did you read this wiki?

Electric does not have liquid chemicals that are hazardous. Electric motors last longer and consume less energy than an ICE. Motors have two components, one is stationary and the other is moving. An ICE has multiple moving parts, in other words, the ICE is more complex and dirtier than a motor, make the motor much more reliable.


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## Mark C (Jun 25, 2010)

I've run the numbers to see if the strictly economic issues warrant an electric conversion, factoring in my own abilities and desire of how to spend my free time. I came up short doing that as well. I could sit back and give up the EV hope I have, but for the problems that still nag at me. 

I really hate who we give a lot of our money to for the privilege of driving ICE powered vehicles. I really dislike the inconvenience of standing outside in the cold / rain / sweltering heat holding onto the handle while filling my car and inhaling the fumes. 

I have test driven several new electric vehicles: a Meyers Motors NMG, a Zenn NEV, a Nissan Leaf & a Mitsubishi i-MiEV. I really like the sensation of each of the electric cars I have driven. So, at the moment I am building a 6.81 kilowatt solar array to power the EV *I will get* one day in the not too distant future. I just haven't sorted out whether I will buy someones lead acid conversion when it is up for sale and upgrade to lithium or buy a new one.


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## Tesseract (Sep 27, 2008)

crunching_numbers said:


> At that rate, I would need to drive the EV for NEARLY 14 YEARS before I break even on my investment, giving up the convenience of a gasoline powered vehicle for every one of them.


Excellent analysis overall, except for your premise that any car will pay for itself. Vehicles used for personal transportation - ie, not a taxi cab, tow truck, etc. - are the very definition of a "depreciating asset". This is most poignantly illustrated by comparing your "fuel costs" for your first car compared to riding a bike or walking! 

Or take the electric part out of the equation and analyze the "savings" you would get from trading in a car you paid $20,000 5 years ago and which gets 20mpg for a new car that costs $22,000* and gets, say, 40mpg. A typical car loses 20% of its value the first year, then 10-15% per year after that**. After 5 years, then, your $20,000 car might now be worth approximately $10,500. If you drive this 20mpg car 12,000 miles per year then you will spend $2,100 per year on fuel, for a total of $10,500. Your total ownership cost, not including maintenance, etc., is $21,000 for 5 years. If you keep this car for another 5 years it will depreciate to $6200 and cost you an additional $10,500 in fuel (assuming fuel prices remain steady at $3.50 for a whole decade - not a bet I'd be willing to make, but, well... this is all hypothetical, right?) Your incremental cost of ownership for years 5-10, then, will be ($10,500-$6,200) + (5 * $2,100) = $14,800.

Now lets say that instead of keeping your old 20mpg beater for 10 years you trade it in at year 5 for a brand new version that costs the exact same amount to you in inflation-adjusted dollars but gets twice the mileage. Once again, after one year your new car will be worth 80% of what you paid for it so that's a depreciation hit of $4400. Assuming fuel still only costs $3.50/gal you will only spend $1050, for a "savings" of $1050, per year. Calculate out the depreciation of the car for the next 4 years and you get a residual value of approx. $11,500, for a net depreciation of $10,500. Your 5-year fuel cost will be much lower at $5,250, true, but your total cost of ownership of the new car is $15750, which still exceeds the incremental cost of ownership of the old car by nearly $1,000.

Of course, the old car will almost certainly incur higher maintenance costs than the new car and the price of fuel is more likely to climb year over year (though it did fall precipitously from 2008 to 2010), both of which favor the purchase of a new car with better mileage than keeping the old beater. 

Conversely, it is quite likely your new car will cost much more than your old car and might not even get better mileage. Perhaps after a couple of promotions over the last 5 years you feel like its time to trade in the Honda for a BMW. I certainly don't begrudge a person success, but somehow I doubt there is ANY economic justification whatsoever in _that_ transaction! 

So, yeah... back to EVs. There are *many* reasons to do a conversion, few of which revolve around the potential economic benefit. Do not be fooled by the legions of clueless n00bs that show up here wanting to convert a piece of junk for the cheapest price possible. Those people are truly the minority, otherwise I can assure that you we (Evnetics, that is) would not still be in business 4 years later...






* - $20,000 times 2% inflation per year for 5 years
** - the depreciation rate is actually somewhat asymptotic, but that just makes this example more confusing and actually reinforces the point I am making, so skipping it is conservative on my part


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## marklaken (Jan 26, 2012)

I'd say the math doesn't work for every scenario and long range highway driving is the least economical for electric. My situation works highly in favor of a slow short range electric car in lieu of a Subaru Outback for in town driving. My quick estimate has a $6000 electric car paid off in fuel savings within 3-5 years. This is much quicker than the $5000 grid tied 3KW solar voltaic system I had installed 2 years ago on my home - my break even on that investment is 14 years.


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## Ziggythewiz (May 16, 2010)

I'd rather give money to local or Chinese parts and battery makers than Opexxon terrorists.

If everyone in America drove an EV we wouldn't have two carrier groups and countless casualties in the Middle East. How's that for real world practicality?


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## MN Driver (Sep 29, 2009)

marklaken said:


> I'd say the math doesn't work for every scenario and long range highway driving is the least economical for electric. My situation works highly in favor of a slow short range electric car in lieu of a Subaru Outback for in town driving. My quick estimate has a $6000 electric car paid off in fuel savings within 3-5 years. This is much quicker than the $5000 grid tied 3KW solar voltaic system I had installed 2 years ago on my home - my break even on that investment is 14 years.


I disagree with the idea that long range highway driving is the least economical for electric driving. I think it is the best. If you can convert a very efficient car body that is roughly around 200wh/mile at 60mph and give it a 25kwh pack. That's about 125 miles. Now if you have a 70 mile round trip you'd use a little under 60% of the pack on each round trip. This allows for pack degradation over the long term, and a low C rate draw driving down the highway, a long possible trip distance when you want to go farther.

Now figure that 200wh/mile car is probably going to get you mid/high 30's MPG in the same condition. Take 2 gallons of gas at $3.50 gallon for $7/day. Compare to 14kwh/day at 10 cents/kwh for $1.40 a day.

You would save $5.60 a day. The pack shipped to your house would be about $10k. $10k/5.6=1786 days of savings, say a 5 day workweek with 70 miles of weekend driving. 297 weeks or about 6 years or about 125k miles. You've broken even at the equivalent of about 625 100% DOD cycles and by the time you've run through that much energy you would still likely have plenty of cycles left over to save another 10 grand. If you use an even more efficient car to convert you could be even better off because you would need less expensive batteries and equipment(stepping down to a Sol Jr instead of a Sol 1 for example and using a 20kwh pack for a 70 mile trip if you get the right car involved).

I think with more driving you'd be spending more money on fuel so you have more opportunity to save. Short trips with a short ranger and the motor, controller, etc. components are fixed costs that take longer to 'pay off'.

If you plan a car right, you can manage a payoff period versus the cost of gasoline. Then keep in mind that your fixed components are still worth something. I still see people successfully selling motors, controllers, chargers, etc for a decent price. Even stuff that isn't top of the line like the ADC, older model chargers, older less capable controllers of a decade old technology, etc are going on the used market for good money. So in the end you've still got assets worth more on the used market than the gasoline equipment in a 10 year old car.

Does it take a long time to break even? Sure, but driving electric along the way is a great experience until you get there. Of course if you want to make like a king and drive a 7777 pound Escalade conversion, ahem, break even is probably not the goal but then again you are getting a steeper discount on the fuel cost by going electric versus burning gasoline since you are using so much more energy.

For what it's worth. I'm in it for the hobby, converting a car that I expect about 160wh/mile at 60mph and going with a ~20kwh pack. Once I earn working money, not break even money, to recover from the cash flow going into the electric car, I'm going to install solar PV on my roof and then my car will be powered by a grid-tie offset and I won't be paying for the electricity. Operating costs for the electric car will be minimal after the initial infrastructure purchases that I make. I should probably suffix all this by saying that I'm not an environmentalist. I'll spend less than a brand new $20k car on the conversion(including donor car), it can never rust out, and I'll be having fun along the way. I'm imagining the day that my mortgage is paid off and my electricity costs for the house and the car are paid by the solar system. There will be plenty of cash flow back in at that point with a very small amount going to the utilities and nearly nothing to the oil companies.


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## Ziggythewiz (May 16, 2010)

MN Driver said:


> I'm imagining the day that my mortgage is paid off and my electricity costs for the house and the car are paid by the solar system. There will be plenty of cash flow back in at that point with a very small amount going to the utilities and nearly nothing to the oil companies.


Then if you can just get the locals to accept carbon credits or something instead of property tax...


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## dougingraham (Jul 26, 2011)

I get asked all the time how long is the payback. In a way this is a stupid question because there is no payback on your ICE car. It is a car and you use it for different purposes. However you can look at it strictly from the standpoint of saving money on gasoline. So how does this compare. If all I did was drive back and forth to work I average 12 miles a day (8.8 miles plus short side trips). My daily driver was my BMW X5 which gets 16 mpg in town. The car I converted is a Mazda RX-7 which also gets 16 mpg doing this 12 mile average daily drive so no real difference. My cost per year for fuel for either vehicle is 4380 miles divided by 16 is 274 gallons or at $4 per gallon which is the national average today a yearly cost of $1095. At the moment I am seeing 311wh per mile measured at the 120vac outlet with a Killawatt meter and 0.11 cents per kwh so that same 4380 miles will cost me $150 per year. A savings of $945 per year. If I had sized my lithium battery pack to just make the 12 miles plus enough so I only reach 70% DOD I would need a 5.3kwh pack which would cost about $2300. The pack would be paid for in just over 2 years from the fuel savings alone. If I could arrange to charge at work the battery pack would be paid for in 13 months even if I have to pay work for the electricity. If work covers the costs of the electricity then it is even less time. If you extend this out assuming the costs of fuel and electricity don't change the motor gets paid for in 2 years. The controller in 3 years. The charger in 2 years. The DC-DC in 1 year. Looking at it like this it does make sense. And those components could be moved to the next car since they really don't wear out in the same way as the ICE motor does.

The problem is that you just can't talk yourself into that short of a range. So my battery payback is 6 years instead of 2. And everything gets paid for at about 15 years. Will I keep this car that long? Probably not but the parts will move to the next car just fine.

I should be getting closer to 250wh per mile and I am investigating why I am not. Part of it has to be that I am driving like a teenager again. The cost of gasoline has traditionally gone up at a rate higher than the cost of electricity which will favor conversions. The cost of the batteries may not come down too much because as near as I can tell about 25% of the current price is traceable to the price of the raw materials. It is just not possible to go below about $25 per AH for new purchases. Since at least 90% of the materials are recyclable it should be reasonable to recover most of the materials costs at some point in the future.

Converting an EV isn't all about saving money. It looks to me like that just sort of is a side effect.


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## EVEngineeer (Apr 11, 2012)

Ziggythewiz said:


> I'd rather give money to local or Chinese parts and battery makers than Opexxon terrorists.
> 
> If everyone in America drove an EV we wouldn't have two carrier groups and countless casualties in the Middle East. How's that for real world practicality?


good point


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## Mark C (Jun 25, 2010)

Ziggythewiz said:


> I'd rather give money to local or Chinese parts and battery makers than Opexxon terrorists.
> 
> If everyone in America drove an EV we wouldn't have two carrier groups and countless casualties in the Middle East. How's that for real world practicality?


I have to agree with this in a big way. Thanks for saying it without sugar coating it!


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## crunching_numbers (Oct 25, 2012)

Wow. I did not honestly expect so many replies. Thank you everyone for you're opinions. I'm going to reply to a few posts that caught my attention, please don't feel like I'm attacking you. I'm not. My sole purpose here is to find the truth about EV conversion vs. original ICE, mostly based on economical benefit. Forgive me if I play devil's advocate with a few of you, it is only to try to offer a fair comparison against a clear bias for EV conversions. (Which one would expect on a forum named "DIY Electric Car"  )



glaurung said:


> Hi Crunchn
> I would suggest you do the numbers again with some upscale vehicle. Try with V12 MB or Beamer. You will find out that you pay your conversion a lot faster if you do not convert a smallest car you can find.Remember that 4x4 vehicles make fast paypack too. Or 4x4 with big V8.
> These beasts use 10 000 euros worth gas a year. That will get you a lot of batteries.
> Regards, Harri, Leguan(ex V12), and Rangie(ex V8)


 While this is true, it really defeats the purpose of the conversion, which is efficiency, right? Why convert an inefficient vehicle that will require an even larger battery pack? I do not have a need for a large gas hog, so converting one to a large electricity hog doesn't make much sense for me.




EVEngineeer said:


> Gas=loud and lots of noise pollution, lots of bad emissions, expensive gas prices, lots of maintenance.
> 
> Electric=less noise, zero emissions, cheap to recharge (free or near free with solar or wind power), little maintenance (Electric does not require periodic tune-ups, filter replacements, SMOG certification, oil changes, weekly dirty and hazardous gas fill ups.). TIME IS MONEY, with less things to worry about with an EV, creates more time for you to spend on more important things.


 I would change the first statement to "Gas=Can actually hear what my engine is doing without checking a gauge" but then again I enjoy the sound of a well tuned gas engine... I'm starting to think I'm part of a minority here. To each their own. You are correct however that time is money, and it would take hundreds of hours to complete a conversion. I didnt do any math on how it would compare to routine maintenance on a gas engine, but my guess is it would again require many years to reach a break even point.



Tesseract said:


> Excellent analysis overall, except for your premise that any car will pay for itself.


 That was not my premise at all. Obviously the car itself will depreciate, and in my case, rust and rot away thanks to Wisconsin's heavy use of road salt in winter. I was attempting to remove the car from the equation all together, and just compare the EV conversion to the factory ICE form. The only purpose of the car is to keep the comparison equal. When the car wears out, you sell/scrap it and get another. It would be no different with the EV conversion, except that you would be wise to remove the EV components before hand and transfer them to the next car. But now you're investing the time in the conversion again, which does not bode well for the comparison of time invested converting/maintaining an EV vehicle vs maintaining the original ICE system.



Ziggythewiz said:


> I'd rather give money to local or Chinese parts and battery makers than Opexxon terrorists.
> 
> If everyone in America drove an EV we wouldn't have two carrier groups and countless casualties in the Middle East. How's that for real world practicality?


 I will not argue this point one way or the other, mainly because I know yes, sending resources to a hostile region of the world is foolish, but also because I know it is not the sole source of funding for terrorists and extremists. You'd also be surprised at how cheaply you can buy an AK-47 or make an IED in that region of the world. One thing I will say is that you are still relying on foreign goods buying batteries from China. And while they may not be openly hostile toward the U.S. (why would they be when we are basically funding their economic boom?) if you do a little digging into their relationship with North Korea you may be surprised.



MN Driver said:


> Now figure that 200wh/mile car is probably going to get you mid/high 30's MPG in the same condition.


Are you suggesting I should've used a 200Wh/mile estimate in my calculations as opposed to the 300Wh/mile figure? I'd be curious to know how you determined this... I don't remember seeing any car or truck conversions in the EV album that were that efficient. Not saying you're wrong, as I don't know. Just need more information to back up your statement.



MN Driver said:


> I should probably suffix all this by saying that I'm not an environmentalist. I'll spend less than a brand new $20k car on the conversion(including donor car), it can never rust out, and I'll be having fun along the way. I'm imagining the day that my mortgage is paid off and my electricity costs for the house and the car are paid by the solar system. There will be plenty of cash flow back in at that point with a very small amount going to the utilities and nearly nothing to the oil companies.


Sort of off topic, but I'm curious why your car will never rust out? I have experimented with a few things with mild success, but they only delayed the inevitable. The only way to keep a body/frame clean in Wisconsin is to park it in the garage for half the year.


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## drgrieve (Apr 14, 2011)

Are you suggesting I should've used a 200Wh/mile estimate in my calculations as opposed to the 300Wh/mile figure? I'd be curious to know how you determined this... I don't remember seeing any car or truck conversions in the EV album that were that efficient.

Most of the conversions on there are lead acid. Which is not efficient. 

Also some measure the charging loss as well, which is not part of the range equation only part of the recharging cost.

As a rough guide at sub freeway speed, and in light traffic a very small and light car will get 200 or less wh/mile - for example MX5 or a CRX. 300 wh/mile for a medium sedan - eg a E36.

Another rough rule of thumb is weight in pounds / 10 is your wh per mile. Seems to work for most conversions.

Another is 100 / MPG * 8. So if your car got 25 MPG you'd expect around 320 wh/mile.


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## Tesseract (Sep 27, 2008)

crunching_numbers said:


> ...please don't feel like I'm attacking you. I'm not. My sole purpose here is to find the truth about EV conversion vs. original ICE, mostly based on economical benefit.


I don't feel like I am being attacked, but I do think that any attempt to find the "truth" about EV conversion is a doomed folly. There is no truth, per se, there is only a miasma of sometimes conflicting, sometimes cooperating motivations, costs and benefits.



crunching_numbers said:


> ...it really defeats the purpose of the conversion, which is efficiency, right? Why convert an inefficient vehicle that will require an even larger battery pack?


I would ask why there has to be just one reason for doing a conversion in the first place? That there can be more than one reason for converting a vehicle to electric is one of the implied arguments of all who responded here. And efficiency is not the primary goal for most people, anyway. Highly efficient ICE vehicles tend to be dull, underpowered and not particularly luxurious; an electric version of the same car can be a helluva lot more fun to drive, and still economical, of course, but it is still just a crappy econobox at heart. 

Converting to electric also lets you breathe new life into a beloved older vehicle whose engine is worn out and not economical (or possible) to fix, or whose performance wasn't all that impressive to begin with, especially when compared to more modern cars. For example, our 1978 Porsche 911 demo car was originally equipped with a 3.0L flat six that put out 180bhp and 237lb-ft of torque. Decent numbers back in its prime, but definitely nothing spectacular these days (the 2.7 L, 4-cylinder non-turbo engine in my old truck put out 220 hp). The electric drivetrain that is in the 911 now delivers nearly twice the power and torque (356bhp and ~480lb-ft) and makes the car an absolute blast to drive. It accelerates so hard you start to get kind of dizzy just holding on for dear life. Hopped up Honda Civics and whatnot run like whipped dogs after they get spanked by our innocuous looking, and nearly-silent baby-crap brown 911 and you really can't put a price on that... 



crunching_numbers said:


> That was not my premise at all. Obviously the car itself will depreciate, and in my case, rust and rot away thanks to Wisconsin's heavy use of road salt in winter. I was attempting to remove the car from the equation all together, and just compare the EV conversion to the factory ICE form. The only purpose of the car is to keep the comparison equal.


Your implied premise - even if not directly stated - was that the improved efficiency of the electric drivetrain would never pay for itself. Ie - paying $0.03 per mile in electricity would never add up to enough savings to pay for the time and materials required to achieve that low of an operating cost in the first place. My counterargument was that rarely will buying a higher mileage ICE vehicle prove to be less overall cost compared to keeping the existing vehicle a little longer. 

You seem to be fixed (hung up, even) on the costs of conversion while ignoring, or discounting, the other tangible and intangible benefits of doing so. That's a valid viewpoint - after all, who are we to tell you what benefits and costs are most important to you? - but by the same token who are you to question what we might find compelling about converting a vehicle to electric? Some people like the challenge, or like to tinker with mechanical or electrical things, or want more performance, or want to save the planet and hug a few trees, or don't want to send money to people and countries that would rather see us dead, or just want to be pioneers (even if that means landing face down in the mud with arrows in the back).

In other words, posting a bunch of calculations here that says an electric car won't pay for itself - whatever that really means - is a lot like telling a bunch of skydivers that they'd be safer if they just stayed in the plane and shut the damn door. Well, duh, but where's the fun in that?


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## Ziggythewiz (May 16, 2010)

crunching_numbers said:


> I will not argue this point one way or the other, mainly because I know yes, sending resources to a hostile region of the world is foolish, but also because I know it is not the sole source of funding for terrorists and extremists. You'd also be surprised at how cheaply you can buy an AK-47 or make an IED in that region of the world. One thing I will say is that you are still relying on foreign goods buying batteries from China. And while they may not be openly hostile toward the U.S. (why would they be when we are basically funding their economic boom?) if you do a little digging into their relationship with North Korea you may be surprised.


You're right. They sell us drugs too, and get significant revenue from the rebuilding projects as well bribe money that we pay the Taliban to allow oil to reach our soldiers to keep them fighting the Taliban. Virtually all of it comes from US, which is just pathetic.

But it's not just about the OPEC nations and what their profits are used for. The oil companies (mostly American) and oil speculators were also directly responsible for the entire economic crash. If oil profits were regulated like every other utility the crash wouldn't have happened, and any bubbles that needed popping wouldn't have had such dire and long lasting consequences.


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## dragonsgate (May 19, 2012)

Back in the good old days when gas was a lot cheaper and Hot Roding was in its heyday hardly anyone gave much thought to gas mileage while bolting duel quads or six deuces onto their Mill. Gas was plentiful packs a lot of energy and as I said was cheap so we could throw 80% of it out the tail pipe and think 15mpg was acceptable if not considered good. The average hot-rodder addressed many of the same issues the EV’er does such as weight, gearing, and aerodynamics. It’s the electricity and storage that makes it different. Even if the goal is to have the fastest car it is overshadowed by how to pack enough joules to get us to the finish line or for us lesser DIY’ers just to get back home after a trip to the store. The fact that we have the energy equivalent of one half to a gallon of gas tends to blind many to the plusses of the EV. Someday the electric storage problem will be fixed and we will be blithely leaving dead electrons along side the road. Then our main concern will be how to make that 4,000 amp controller sound like a set of four barrels kicking in.


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## MN Driver (Sep 29, 2009)

crunching_numbers said:


> Are you suggesting I should've used a 200Wh/mile estimate in my calculations as opposed to the 300Wh/mile figure? I'd be curious to know how you determined this... I don't remember seeing any car or truck conversions in the EV album that were that efficient. Not saying you're wrong, as I don't know. Just need more information to back up your statement.


It isn't hard to find a vehicle that is lightweight and aerodynamic enough to beat 250wh/mile. I probably should have used that number instead. As others have said there is some losses in the efficiency of charging as a good efficient charger might be about 93% efficient and you'll lose a little going into the battery too. 90% would be a good round number for figuring for both if you are using lithium. With lead-acid, like most of ev-album you can pull 4kwh out and put 6kwh or more back in which is very inefficient, they also have voltage sag like rocks so you pull even more amps out while getting less power from those amps you are drawing.

If you use a smaller car with decent aerodynamics such as .35 or lower and it is on the lighter side you stand a chance of being under 250wh/mile. Here's a decent list of this.
http://en.wikipedia.org/wiki/Automobile_drag_coefficient

As an example from EValbum Tom (tomofreno on this forum) has a 2001 Suzuki Swift that over the past two years his measured consumption from the wall was pretty good. 14617 miles for $315.98 of electricity if your rate is 10 cent/kwh. If we figure $3.50/gallon of gas that's 90.28 gallons of gas. On a cost equivalent basis you'd have to get 161.9mpg to beat the fuel operating cost. Of course electric rates vary but gas prices has historically climbed much faster than electricity and I consider that will remain true.
"TWO YEAR UPDATE:
12/5/11: 2 years operating as an ev now. 14,617 miles, 
3159.81kWh energy used from the wall (EKM reading), 
216Wh/mile from the wall. No issues over the past year, 
no down time."
http://www.evalbum.com/3060



> Sort of off topic, but I'm curious why your car will never rust out? I have experimented with a few things with mild success, but they only delayed the inevitable. The only way to keep a body/frame clean in Wisconsin is to park it in the garage for half the year.


It's not that off topic because a car that doesn't rust will last longer as that is the primary thing that destroys cars up at our latitude. The car I'm converting is aluminum. I weighed the car at 1835 pounds and if I remove the weight of the gasoline and the backpack in the back it's about 1810 pounds. It has the same crash ratings as the same model year Civic, Corolla, or most other compact cars at 4 stars all around because since aluminum is lighter they can use more metal in a strategic way that they can't with steel to make it a safer material to build with versus steel. cD is .25 and it is the most efficient car to drive at highway speeds or in the city that you can readily get and convert to electric.

http://www.insightcentral.net/encyclopedia/enaluminum.html

It's also a very low cost donor car, there are cars nearing 13 years old and you can find an owner selling one with a bad battery for less than the same model year Civic, rust not included and drive it home to convert. Even with a good battery they come pretty cheap because of the decade old age and usually higher miles along with it being a 2 seater which weeds out most of the market.

Someone who already converted their 1st Gen Insight to electric was getting 140wh/mile driving at 55mph using a GM EV1 motor with a homemade controller. I'm not using the same equipment but have been figuring that cruising at 60mph on the highway in good weather will be around 160wh/mile but will probably be better. I mostly drive on the highway and the speed limits are 55-65 around here and traffic usually holds close to those speeds. I'm building my car primarily with highway driving in mind.


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## crunching_numbers (Oct 25, 2012)

Tesseract said:


> The electric drivetrain that is in the 911 now delivers nearly twice the power and torque (356bhp and ~480lb-ft) and makes the car an absolute blast to drive. It accelerates so hard you start to get kind of dizzy just holding on for dear life. Hopped up Honda Civics and whatnot run like whipped dogs after they get spanked by our innocuous looking, and nearly-silent baby-crap brown 911 and you really can't put a price on that...


Now those are some impressive numbers! care to share some of the details of the setup? I'd be curious to know how much a conversion of that magnitude would cost, how large your battery pack is, and how much range is affected by the hotter performance.



Tesseract said:


> Your implied premise - even if not directly stated - was that the improved efficiency of the electric drivetrain would never pay for itself. Ie - paying $0.03 per mile in electricity would never add up to enough savings to pay for the time and materials required to achieve that low of an operating cost in the first place. My counterargument was that rarely will buying a higher mileage ICE vehicle prove to be less overall cost compared to keeping the existing vehicle a little longer.


And I would wholeheartedly agree with that counter argument. Which is why I like to buy my vehicles around 8-10 years old with a few minor problems to get a screaming deal. Fix those problems and drive for 3-5 years and I can usually unload them for close to what I originally paid due to inflation. For example, I bought my current car, a '99 Dodge Neon, back in May of 2008 for $1000 with 93k miles on it. It needed some touch up work here and there, I replaced some interior pieces that were broken or missing, and I think it needed a front brake job and tires at the time. Four and a half years and a deer collision later it now just turned 160k and I'm looking to unload it for $1200-$1500 next spring before it's due for any major maintenance. Most expensive thing I've bought for it was a new hood, radiator and headlights after hitting the deer. True its not as nice as when I bought it, but if you buy a car cheap enough, inflation usually covers you on the depreciation side of things.  And, I will only buy a vehicle that gets equal or better fuel mileage than my last... which may explain why I've owned 3 neons as daily drivers. 



Tesseract said:


> In other words, posting a bunch of calculations here that says an electric car won't pay for itself - whatever that really means - is a lot like telling a bunch of skydivers that they'd be safer if they just stayed in the plane and shut the damn door. Well, duh, but where's the fun in that?


I got a kick out of that one. I'm starting to see that EV conversions seem to be more about originality than saving money. Which is fine, unfortunately at this stage in my life with the current economy I can't afford to be as original as I'd like to be.



MN Driver said:


> It isn't hard to find a vehicle that is lightweight and aerodynamic enough to beat 250wh/mile. I probably should have used that number instead.


 I re-ran my numbers at 250Wh/mile and it came out a little cheaper, obviously, but still not cheap enough for me to pull the trigger on a conversion. Unfortunately the cost of the battery pack is what's really adding to the cost per mile, and a difference of 50Wh/mile doesn't allow a much smaller pack for my needed range. Do you know if there are new LiFePo cells available anywhere for less than $1.35/Ah? That is the cheapest rate I've found and the one I've been using for my calculations.



MN Driver said:


> It's also a very low cost donor car, there are cars nearing 13 years old and you can find an owner selling one with a bad battery for less than the same model year Civic, rust not included and drive it home to convert. Even with a good battery they come pretty cheap because of the decade old age and usually higher miles along with it being a 2 seater which weeds out most of the market.


Very Interesting! I did not know the Insight's unibody was aluminum. Are all of the body skins aluminum as well? (I would hope so... steel skins on an aluminum frame wouldn't make much sense.) The only problem is after a quick search I only found a handful for sale in my state, and nearly all of them where going for 5 figures. One was $2000, but the body was ROUGH... must've been in some sort of light accident and was never fixed. Definitely seems like the best EV conversion candidate so far though, if I can only find a way to lower the cost of the battery pack.


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## drgrieve (Apr 14, 2011)

Calb should around $1.25 ah. Winston was a bit over $1 an ah not sure if you can still get them state side - maybe china only now.

Sinopoly is around $1.10 I believe.

Then there is grey-market A123 cells they are under $1 ah in bulk.

Then there is HiPower and other various lesser brands they would all be around the 1ah mark.

Not including shipping.


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## Tesseract (Sep 27, 2008)

crunching_numbers said:


> Now those are some impressive numbers! care to share some of the details of the setup? I'd be curious to know how much a conversion of that magnitude would cost, how large your battery pack is, and how much range is affected by the hotter performance.


The 911 serves as our test-bed and demo vehicle so what was spent in converting it is not terribly applicable to others. Right now it has twin Soliton1 controllers (set to 750A battery side, 1000A motor side) driving twin WarP-9 motors all powered by a rather-abused 96s6p pack of 8Ah Headway cells (ie - we are asking up to 31C of the cells)

Range is inversely proportional to performance in all cars, but one of the nice things about an EV is that you don't pay a penalty in energy usage (ie - get worse mileage) if you are easy on the throttle. Thus, if you drive our 911 like it is an ordinary car with an ordinary power to weight ratio you get an honest ~45 miles of range (mixed city/highway driving). If you drive the 911 like it *ought* to be driven then, yes, the range does drop, but how much is totally under your control (unless you are running from the cops or something... ).


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