# Electric car economical feasibility



## mdimarco (Oct 22, 2013)

Lets take average joe. He drives 15 miles to work everyday and 15 miles back. His wife has a car to cart the family around and run errands. Joe asks you (the electric car expert) if he can save money by making an electric car to use as his commuter. 

Well lets do the math for Joe.

30 miles * 5 days a week * 4 weeks a month * 12 months a year = 7200 miles a year. MPG of his current car is 25. 7200/25 = 288 gallons of gas a year.

Cost of gas $3.20 * 288 gallons = $921 a year.

Lets be conservative and say he could get 75 mpg equivalent with a homemade electric car using a DC motor (the leaf gets 115 mpg equiv). There are 33.7 kwh in a gallon of gas also the price per kilowatt hour is about the same for gas and electricity, about 10 cents.

So he would spend 1/3 the price of gas to run his electric car. He would save 2/3 of his gas cost a year.

2/3 * 921 = $614 savings per year.

So you tell Joe a pack on average will last between 5-10 years well maintained. So on the low end you could save $6000 in 10 years in gas. You tell Joe that a lead acid pack to fulfill his needs would cost him roughly $1000 (12kwh) every 5-10 years.

Joe exclaimes; Thats great! So you are saying I could save 4-5 thousand every 10 years? Thats like 400-500 bucks a year.

Yup you can.

Excellent, How much does it cost to build?

You rack through your mind and say well a couple grand for a controller, 1k for batteries, 500 for the motor, a few hundred for cables, a thousand or two for a rolling frame... "6k?" you say

He says; not bad thats like a used car. Also if you say I can save 4-5k every 10 years and the car lasts me ten years I only spent 1-2k on the build!

Nice point Joe.

And you say oh ya and there is no maintainance that you can't easily do. No oil changes, no transmission problems, no messy grimy parts, no cramped spaces. No more thousand dollar repair bills or 16 hour days trying to fix something little in the engine.

Joe says: Wow what a relief! Why isn't everyone doing this, there is no downside! Count me in!


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## Logan (Sep 28, 2013)

Sorry, I dont get it...

Lets say I´m this average joe.
You tell me, I´m saving 614 bucks a year.
Great - 6140 in ten years.
You say that I need 6000 to change to e-drive.
140 left - and I spend the 6000 right now.
Without the switch to e-drive, the last 614 bucks I´d spend 2023 right?
Since we dont know how much repairs I´ll need over this period, I wouldnt take them in account.
Additional price I do have to pay - I never ever can drive 300 miles in one take without refueling.
I tell you, you need to have a heart for the environment to do this (what I happen to have  ). 140 bucks in 10 years is no reason...
My opinion ...


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## major (Apr 4, 2008)

mdimarco said:


> You tell Joe that a lead acid pack to fulfill his needs would cost him roughly $1000 (12kwh) every 5-10 years.


Show me this. Proof please.

ps. Please add your location to your profile so we can see where you're from.


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## mdimarco (Oct 22, 2013)

Logan said:


> Sorry, I dont get it...
> 
> Lets say I´m this average joe.
> You tell me, I´m saving 614 bucks a year.
> ...


According to your numbers you save 140 in 10 years but you also had a car to drive. If you were in the market to buy a new (used) car that got 25 mpg you would have lost $6k at the end of the 10 years. In the case of this electric car you lost $0. And if you sold the car after 10 years for say 3k, you made 3k pure profit. If you bought a gas car instead of te electric and sold it for 3k after 10 years you are still 3k in the hole. Make sense now?

I don't want to put my location at this point. Looking at T-105 type batteries you get around 1.4kwh per $130. 6 volts and 225 ah (or some similar to the t-105 are 235 ah). 62 lbs each. So at 14 kwh pack your looking at $1300 and 620 lbs.


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## major (Apr 4, 2008)

mdimarco said:


> I don't want to put my location at this point. Looking at T-105 type batteries you get around 1.4kwh per $130. 6 volts and 225 ah (or some similar to the t-105 are 235 ah). 62 lbs each. So at 14 kwh pack your looking at $1300 and 620 lbs.


Just seems like you're not from around here; maybe a different planet 

Like I suspected. You're using spec sheet numbers for a 20 hour rate. Do an actual discharge test at a reasonable rate for an EV like 1C or 2C and measure the actual energy. Then subtract 20% to avoid the deep discharge which kills Pb-Acid batteries early (even deep cycle floodies). Now what is the real life energy? I showed my test; you could expect similar results. Ref: http://www.diyelectriccar.com/forums/showthread.php?t=78826


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## frodus (Apr 12, 2008)

mdimarco said:


> 30 miles * 5 days a week * 4 weeks a month * 12 months a year = 7200 miles a year. MPG of his current car is 25. 7200/25 = 288 gallons of gas a year.
> 
> Cost of gas $3.20 * 288 gallons = $921 a year.
> 
> ...


I realize I'm adding to your argument, but there are a few issues:

1) You forgot the other 4 weeks a year. 52 weeks in a year.... so 30mi * 5 * 52 = 7800, or $998.40, lets call it $1k. Not much difference, but it only helps your argument.

2) Yes a gallon of gas is about 33.7kwh of energy. The problem is, gas engines are really inefficient, at best maybe 20% (that's the general consensus). So that 33.7kwh is really more like 6.75kwh of energy at the wheels. To check that, lets use the 6.75kwh and divide by 25mpg, that would give you rougly 270wh/mi. That sounds about right for a small car.

So gas costs $3.20 per 6.75kwh of usable energy, or nearly $0.48/kwh. That's almost 5 times the cost of electricity, which you said is around $0.10/kwh.

So going by estimates only, that $1,000 now becomes ~$200 to drive electric, a savings of over $800/year.


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## mdimarco (Oct 22, 2013)

major said:


> Just seems like you're not from around here; maybe a different planet
> 
> Like I suspected. You're using spec sheet numbers for a 20 hour rate. Do an actual discharge test at a reasonable rate for an EV like 1C or 2C and measure the actual energy. Then subtract 20% to avoid the deep discharge which kills Pb-Acid batteries early (even deep cycle floodies). Now what is the real life energy? I showed my test; you could expect similar results. Ref: http://www.diyelectriccar.com/forums/showthread.php?t=78826


Yup, I'm from the real world. I know you don't get many visitors from my planet .

Yup I'm using a 20 hour discharge rate. And yup I'm tacking on 20% for deep cycle lead acid. Fine lets use the 2 h rate as a worst case scenario (which it isn't because he is probably only averaging 5 hp during the commute and is letting the pack rest (or even charge) for 8 hours at work). But it good to have an upper bound on what he would need. You still get 146 ah * 6v. At 0.35 kw/ mile he needs roughly a 10kw pack. Multiply that by 1.2 for lead acid, 12kw pack. At .87 kw per battery he would need 14 batteries. The total cost would be $1800 for the pack and 868 lbs. 

Since you are bieng so picky why don't you post the price of a 10 kw lithium pack at 2 hour discharge rate for comparison?


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## mdimarco (Oct 22, 2013)

Frodus I think the 33 kwh per gallon of gas is constant but its the miles you can get from that energy is what sets the electric car apart. Basically if a gas car is 20% efficient to get 25 mpg, than an electric car is 60% efficient to get 75 mpg out of it. So my thought is the mpg takes into account efficiency so my numbers are right. But ya you're right about the weeks, I should have just used 52 weeks. But mabye my method is good because it accounts for vacation time .


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## frodus (Apr 12, 2008)

There are some major issues with your lead assessment.

Look at this:









If you discharge to 80%, you're only going to get maybe 2-300 cycles out of T-105's. Lets say you design a pack such that you discharge to 80% for every 30 mile commute. 5 days a week, 52 weeks a year, that's 260 cycles, and now your batteries are almost completely toast.

Next, look at the datasheet for the T-105's. You're looking at a 20-hour rate (225Ah). On the datasheet, there is a listing for the 2-hour rate, and it's 146Ah. That's what we call the peukert effect. The more current you draw, the less capacity you'll get. 

Now, plot those rates (from the datasheet) versus Ah and you get this:









See that drop off? You're down in the 100Ah for 1-hour rate.

So lets lets be optimistic, and use a 2-hour rate. That's 146Ah. Now you only want to go 80% otherwise you won't last a year. That 146Ah becomes 116.8Ah. 


That's about 1/2 of the 225Ah 20-hour rated capacity, just like we've been trying to tell you.


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## frodus (Apr 12, 2008)

mdimarco said:


> Since you are bieng so picky why don't you post the price of a 10 kw lithium pack at 2 hour discharge rate for comparison?


Lithium has a very very low (almost non existent) peukert effect. They're also not rated at 20-hour rates. All lithium datasheets list the 1-hour rate, so they've already done that for you. When they say 100Ah, it's 100Ah at a 1-hour rate.


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## frodus (Apr 12, 2008)

mdimarco said:


> Frodus I think the 33 kwh per gallon of gas is constant but its the miles you can get from that energy is what sets the electric car apart. Basically if a gas car is 20% efficient to get 25 mpg, than an electric car is 60% efficient to get 75 mpg out of it. So my thought is the mpg takes into account efficiency so my numbers are right. But ya you're right about the weeks, I should have just used 52 weeks. But mabye my method is good because it accounts for vacation time .


Nope..... not really. That 33.7kwh is the energy in the gas, not what you get out of it.

Lets say the 270wh/mi that I calculated above on the gas is what the electric would also use. 30 miles would use 8.1kwh and cost you $0.81/day to charge. Now multiply that by 5days * 52 weeks and you get $210.60. 

That's not far off from my $200 estimate.


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## major (Apr 4, 2008)

mdimarco said:


> Since you are bieng so picky why don't you post the price of a 10 kw lithium pack at 2 hour discharge rate for comparison?


I will sell you 12 kWh brand new made in USA Lithium for $3840. Good for 3000 deep cycles. Weighing 264 Lbs. 

That is a bit over twice your Pb-Acid price, but will last 4 times longer and weigh less than one third giving you greater payload with less stress on things like chassis and brakes. Oh yeah, I threw in an extra 20% in energy. And better cold weather performance. And greater efficiency, so less wasted energy charging. 

While you're at it, double that to 24 kWh of Lithium and you have what is in my EV. I already have over 400 cycles. Still running like new. Got about a solid 80 mile range. It handles well. 

How is your Pb-Acid EV running?


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## frodus (Apr 12, 2008)

Major, at 1hour rates, the cycle life on the T-105's is ~300 cycles. In that case, Lithium would last 10 times longer than the T-105's.


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## Hollie Maea (Dec 9, 2009)

Not to pile on with the "You forgot the Peukert effect" crowd, but let's throw some real numbers into the mix.

You mentioned a 12kWh pack. That's pushing the limits with how big of a Lead pack you can fit in a car, so we won't be going any bigger than that.

Running at the 20 hour discharge rate, your pack can deliver a whopping 600 Watts of power. I don't think Mr. Average Joe is going to be content with that.

So you decided to be "Generous" and go with the 2 hour rates. Now we are up to 6kW. Still not enough to move a car reasonably. The fact is that the smaller your pack is capacity wise, the more power density you are requiring. And that's a big problem with a battery that loses capacity when you increase your power draw.

Look at it from another perspective. Lets say your car draws 250wh/mile, which is fairly standard (though generous for a lead sled). Taking into account the 20% depth of discharge rule, you would have a 40 mile range with this pack. To keep your discharge rate at two hour levels, you have to keep your speed below 20mph. So, Average Joe has an overpriced golf cart.

The part that people like you often overlook, is that it doesn't matter how big you make your pack: you still have to get the power out of them at a decent rate for it to be usable. With lead, which works best with discharge times from around 5-20 hours, that's a problem. With lithium, which works well with discharge times from 20 minutes to 2 hours, it's well suited for EVs.

Edit: I should note that I am assuming that you would get your full 40 miles out of your "12kwh" pack. Of course you won,'t BECAUSE OF PEUKERT. So you'd have to go even slower to stay at the 2 hour discharge rate. To find out exactly what your range would be and how slow you would have to go would require recursive calculations. OR, you could recognize that you have no idea what you are talking about, and that this board is full of people who were around with lead was the only option, and they know precisely what lead can and can't do, and what lithium can and can't do. Five years ago, you'd have gotten a couple of diehards on your side. These days, everyone knows better.


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## major (Apr 4, 2008)

frodus said:


> Major, at 1hour rates, the cycle life on the T-105's is ~300 cycles. In that case, Lithium would last 10 times longer than the T-105's.


So with those, in my EV, I'd be half way thru my second set and be carrying around an extra half ton 

Some guys like Pb-Acid. That guy I did those tests for and change out in his Gem is perfectly O.K. with them. We got his charger programmed correctly (thanks). And we put in a central watering system. He used it all summer at 5 to 10 miles under 40 mph. Was happy with it. I think that was his third battery set. He doesn't drive it in the winter. Hopefully it will give him a few more years.

Imagine your bike on Pb-Acid frodus? How much fun would that be


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## PStechPaul (May 1, 2012)

I'd like to add a few calculations and corrections to the OP's assertions. For one thing, a car needs considerably more than 5 HP average for a commute. For a small 2200 lb (1000 kg) vehicle, with an average speed of 50 MPH (80 kmph) on flat roads, the power needed is about 8.6 HP, so considering efficiency of the electric system it is more likely 10 HP or 7.5 kW. Regen might improve on that, but acceleration and driving habits probably cancel out. So a 30 mile daily commute uses 130 Wh/mile (but we know that real world consumption is closer to 250). The daily usage is 30*250=7.5 kWh.

A lead-acid pack would need to be about twice that for true capacity, so 15 kWh, which could be done with 12 100Ah deep cycle Walmart batteries at about $70 each or $840 and about 800 pounds. Lifetime is probably about 2 years and they may have as much as $200 scrap value. So batteries would be about $300 per year. Electric cost for 300 days per year of commuting 30 miles at $0.12/kWh is $1080. So about $1400/year.

My car averages about 35 MPG for commuting and it cost $4200 and probably $500/year maintenance, so figure $1000/year. Fuel cost would be $3.50 * 300 *30 / 35 = $900. So total cost for ICE transportation is about $2000/year.

For the DIY electric, you will probably spend about the same $4200 for a car to convert, including necessary modifications for the electric system. The motor and controller are probably $3000 but will probably retain most of their value after 10 years. The battery pack for 10 year lithium is about $4000 or $400/year compared to $300/year for lead. The lithium may save a lot of energy due to weight and may still retain 80% capacity after 10 years, so it is a good investment, but the lead batteries require much less expenditure up front.

Thus, the total cost for ICE is about $2000/year with very little scrap value, while the EV is about $1800/year and possibly about $200/year retained value in the batteries if you use lithium.

The EV comes out a little better over the long run, but I used a very optimistic figure for the Wh/mile. But the ICE car has an up front cost of $4200 and you just get in and drive, while the up front cost of the EV has an additional up front cost of about $8000 and you have to invest a lot of time and effort (or more money for professional design and installation). So based purely on economics, and the fact that you can drive 400 miles on a tank and fill up in 5 minutes everywhere, the ICE car still wins. But based on environmental factors and the EV grin, the electric car is much better and breaks about even on overall cost.


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## PhantomPholly (Aug 20, 2008)

frodus said:


> Nope..... not really. That 33.7kwh is the energy in the gas, not what you get out of it.
> 
> Lets say the 270wh/mi that I calculated above on the gas is what the electric would also use. 30 miles would use 8.1kwh and cost you $0.81/day to charge. Now multiply that by 5days * 52 weeks and you get $210.60.
> 
> That's not far off from my $200 estimate.


We ran this exercise last year. I believe the consensus is that 8Kwh of batteries is roughly equivalent to the usable propulsive power from a gallon of gas. Thus the Nissan Leaf @ 24Kwh has roughly a 3 gallon tank.


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## mdimarco (Oct 22, 2013)

frodus said:


> Lithium has a very very low (almost non existent) peukert effect. They're also not rated at 20-hour rates. All lithium datasheets list the 1-hour rate, so they've already done that for you. When they say 100Ah, it's 100Ah at a 1-hour rate.


Ok, so what is the price for a 10kw lithium pack so we can compare?


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## major (Apr 4, 2008)

mdimarco said:


> Ok, so what is the price for a 10kw lithium pack so we can compare?


Didn't you read this? 


major said:


> I will sell you 12 kWh brand new made in USA Lithium for $3840.


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## frodus (Apr 12, 2008)

*mdimarco,*
*Go back and read the entirety of page 1 if you have not done so. **Especially this post.*

With 10kwh of USEABLE energy coming into the controller from the battery pack, a ~270wh/mi car would go between 35 and 40 miles. 

With a 10kwh lithium battery pack would have no trouble getting all of that energy back out. They're rated in 1h rates already, very very small peukert, higher DOD ability without effecting the cycle life a ton. 

In order to get 10kwh of useable energy from a Lead Acid pack, you'd have 115Ah per 6V T-105 at 1hour rates..... or about 690Wh each. You'd need 15 T-105's to get 10kwh of useable energy. Lets say they're $150, that's $2250 for 10kwh useable of lead acid.

Major estimated ~$3840 for a 10kwh lithium pack. CALB would be roughly $4k or so. They'd both last over 2000 cycles. The T-105's are maybe 300 cycles if you're lucky. 

So lets compare a 2000 cycle life of each. To get 2000 cycles on lead, you'd have to purchase 2000/300 = 6.667 (7 packs are purchased and the last one isn't completely used up). 7 packs of T-105's at $2250 would cost you $15750. obviously subtract a minor amount for core charges.

So you're promoting the idea that people should NOT spend $4,000 for a Lithium pack that'll last 2000 cycles..... but rather they should spend $15,750 for enough lead acid to go 2000 cycles. 

Sounds legit.


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## mdimarco (Oct 22, 2013)

frodus said:


> There are some major issues with your lead assessment.
> 
> Look at this:
> 
> ...


Alright thanks for those graphs they are useful. Problem is you were on the wrong curve. The T-105's are on the top curve. So at 80% every day we are at 3 years. Would be good to get a comparison with that lifespan with lithium under the same workload.

Besides that, noone will drain their pack in 1 hour. It would be good to see what an actual average commute puts the capacity at. For one it is not continuous load. Secondly there is an 8 hour rest for the pack (even assuming you can't charge at work). Therefore I don't feel you can say a pack is 1/2 the usable amp hours vs lithium. Mabye if you put it under full load until it dies yes. But under normal driving no.


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## mdimarco (Oct 22, 2013)

frodus said:


> Nope..... not really. That 33.7kwh is the energy in the gas, not what you get out of it.
> 
> Lets say the 270wh/mi that I calculated above on the gas is what the electric would also use. 30 miles would use 8.1kwh and cost you $0.81/day to charge. Now multiply that by 5days * 52 weeks and you get $210.60.
> 
> That's not far off from my $200 estimate.


Ok I assumed 350 wh/mile. That may be where the difference comes in. But do you see that I took the 33kw per gallon of gas but used 25 miles per gallon and electric 75 miles per gallon? You didn't use mpg but I did and that accounts for the efficiency difference in gas vs electric automatically.


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## mdimarco (Oct 22, 2013)

major said:


> I will sell you 12 kWh brand new made in USA Lithium for $3840. Good for 3000 deep cycles. Weighing 264 Lbs.
> 
> That is a bit over twice your Pb-Acid price, but will last 4 times longer and weigh less than one third giving you greater payload with less stress on things like chassis and brakes. Oh yeah, I threw in an extra 20% in energy. And better cold weather performance. And greater efficiency, so less wasted energy charging.
> 
> ...


Running great thanks. Well I would like to see some proof on the 3000 cycles. And even if it were correct and could be discharged 100% each time without loosing capacity it is most likely bad after an amount of years anyway regardless of how many cycles you get out of it.

And don't forget to add battery management and cooling system costs to your quoted price.


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## mdimarco (Oct 22, 2013)

Hollie Maea said:


> Not to pile on with the "You forgot the Peukert effect" crowd, but let's throw some real numbers into the mix.
> 
> You mentioned a 12kWh pack. That's pushing the limits with how big of a Lead pack you can fit in a car, so we won't be going any bigger than that.
> 
> ...



Lol. First of all I don't care if noone is on my side. I'm used to it. Story of my life. I bet you could easily find 10 incredibly innovative people in history and same story. There is a reason certain people are revolutionary, it is because they are revolutionary (not normal) thinkers.

Who says I haven't been around since lead was the only way? And it never was the only way the big spenders back then used nicad. Heck laptops didn't even use lithium back then. Heck I don't even know if laptops existed. And ya your beating a dead horse about amp hour rates because show me a person that continuously hits the accelerator for 2 hours. The discharge is spread out over a long period of time. On here off there, 8 hour break, ect. Until you can use some real commuter data to back up your points I feel 2 hours continuous is more than an adequate rating. And you are saying a low voltage motor overvolted to 60v pulling the max current a zilla can deliver at 1000 amps is slow? lol. And again that is assuming someone is holding their foot on the accelerator without letting up for 2 hours straight. Noone drives like that. Very likely you could get more juice out of it than that.


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## rwaudio (May 22, 2008)

mdimarco said:


> Lol. First of all I don't care if noone is on my side. I'm used to it. Story of my life. I bet you could easily find 10 incredibly innovative people in history and same story. There is a reason certain people are revolutionary, it is because they are revolutionary (not normal) thinkers.
> 
> Who says I haven't been around since lead was the only way? And it never was the only way the big spenders back then used nicad. Heck laptops didn't even use lithium back then. Heck I don't even know if laptops existed. And ya your beating a dead horse about amp hour rates because show me a person that continuously hits the accelerator for 2 hours. The discharge is spread out over a long period of time. On here off there, 8 hour break, ect. Until you can use some real commuter data to back up your points I feel 2 hours continuous is more than an adequate rating.


With a 17.6kwh lithium pack (14kwh usable) in my car I can easily drain the pack completely in 1/2 an hour, or driving more conservatively in an hour. These are normal numbers, I would have to be driving VERY slowly to get 2 hours out of it.

I would say the 1 hour numbers are much more realistic as a baseline. Then adjust up/down based on pack size vs energy usage.

I don't think that lead and revolutionary belong in the same sentence, I'm not sure what you are going for there but I couldn't disagree more.

You could say Tesla using laptop batteries and taking advantage of the existing economy of scale in that industry is revolutionary.


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## mdimarco (Oct 22, 2013)

PStechPaul said:


> I'd like to add a few calculations and corrections to the OP's assertions. For one thing, a car needs considerably more than 5 HP average for a commute. For a small 2200 lb (1000 kg) vehicle, with an average speed of 50 MPH (80 kmph) on flat roads, the power needed is about 8.6 HP, so considering efficiency of the electric system it is more likely 10 HP or 7.5 kW. Regen might improve on that, but acceleration and driving habits probably cancel out. So a 30 mile daily commute uses 130 Wh/mile (but we know that real world consumption is closer to 250). The daily usage is 30*250=7.5 kWh.
> 
> A lead-acid pack would need to be about twice that for true capacity, so 15 kWh, which could be done with 12 100Ah deep cycle Walmart batteries at about $70 each or $840 and about 800 pounds. Lifetime is probably about 2 years and they may have as much as $200 scrap value. So batteries would be about $300 per year. Electric cost for 300 days per year of commuting 30 miles at $0.12/kWh is $1080. So about $1400/year.
> 
> ...


Again just like everyone ere you give lead the minimum possible (2 years) and lithium the maximum possible (10 years) and lead still comes out ahead, I love it. Also don't forget a good cooling system and battery management. Don't want to see your batteries ending up like a laptop battery burns out after a year.

Also your more sophisticated hp calculation just solidifies my guess of 5 hp average. You may not have realized most peoples commutes are more around 20-40 mph and on top of that significant downtime. Sounds like my 5 hp average number may even be an overestimate.


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## Duncan (Dec 8, 2008)

_The discharge is spread out over a long period of time. On here off there, 8 hour break,

_*That would be nice!* 

Unfortunately that is not how it worksIn the real world it is the instantaneous discharge that counts_, _so if you discharge at 4C and then rest - it is the 4C discharge that is important_.

_So for a Lead Acid you need to use Peukert at the *actual discharge rate* average discharge is meaningless


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## mdimarco (Oct 22, 2013)

frodus said:


> *mdimarco,*
> *Go back and read the entirety of page 1 if you have not done so. **Especially this post.*
> 
> With 10kwh of USEABLE energy coming into the controller from the battery pack, a ~270wh/mi car would go between 35 and 40 miles.
> ...


Your numbers are wrong, see my numerous other posts. You read your graph wrong.


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## mdimarco (Oct 22, 2013)

Duncan said:


> _The discharge is spread out over a long period of time. On here off there, 8 hour break,
> 
> _*That would be nice!*
> 
> ...


Where did you get that info from?


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## PStechPaul (May 1, 2012)

I have a Peukert calculator on http://enginuitysystems.com/EVCalculator.htm.

A 100 Ah lead-acid battery at a 2 hour discharge rate is 33 amps. If you have 12 batteries of 12V each that is 144V and 4.75 kW, or 9.5 kWh. As I mentioned previously, 4.75 kW or 6.4 HP is about the bare minimum for a 2200 pound vehicle on flat roads at 40 MPH. This is only 115 Wh/mile, which is about half of what most DIY EVs average, and gives 80 miles range with 100% DOD.

With very conservative driving and a very lightweight vehicle, I think it might be possible to get 50 miles range, but the batteries will age and after a year it will probably drop to 40 or 30 miles. The weight of the batteries is about 800 pounds so there is only about 1400 pounds left for the vehicle and driver and payload. 

If you can deal with the loss of range you might be satisfied with a lead sled. It might even be a good choice for infrequent use, and it may be more affordable up front with $1000 of batteries and maybe a couple hundred scrap value, but for a daily commuter you will probably need to replace them 5 or more times over 10 years. The lithium option might be $5000 including BMS and charger, and probably will have $2000 of value after 10 years. 

I'm really on your side, but I also see the argument for lithium. If you can afford the up-front cost, lithium is clearly superior, especially if you want to drive on the Interstate or are tempted to drive aggressively. There is also the possibility of new or drastically cheaper batteries becoming available in the next few years so that might be a worthwhile gamble. 

[edit] With the Peukert factor, the best performance is for a continuous drain over the 2 hour time you are spending on the commute. As shown above, you may theoretically get 80 miles range at 40 MPH. If you go 60 MPH your power usage goes to 12 HP or 9 kW, current drain is 62.5A at which the effective discharge time is 0.9 hours and even at 60 MPH you can only go 54 miles. The more often you stop and go, the more time you will spend accelerating and braking, which greatly reduces the range. There are also many other factors that cause higher current drain, such as drive train efficiency, and the fact that lead batteries sag more than lithium so the 144V I used for current draw will drop and raise the current for the same power, causing even more Peukert effect. This nonlinearity is why lead is not used for most serious DIY conversions.


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## mdimarco (Oct 22, 2013)

Geeze I've gotten everyones panties in such a twist I have to babysit my post lol.

You guys should be happy I am proving an electric car can be very cost effective for a majority of americans. All I get is nit picking and hate from electric car people nonetheless, heck I would get way more love from smart non-electric car ppl lol.


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## major (Apr 4, 2008)

mdimarco said:


> Well I would like to see some proof on the 3000 cycles.


http://elithion.com/pdf/enerdel/MP310-049.pdf This has been validated to automotive standards.



> And even if it were correct and could be discharged 100% each time without loosing capacity it is most likely bad after an amount of years anyway regardless of how many cycles you get out of it.


It is correct and does lose a small amount of capacity. See the chart in the reference. About 10% after 3000 cycles. I think calendar life is in excess of 10 years. There is also some loss of capacity. That chart is included in the reference also.



> And don't forget to add battery management and cooling system costs to your quoted price.


Battery cooling system is not required for EV applications. BMS is needed, of course. My quoted price does not include BMS. See my thread in the classified forum for detail.


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## major (Apr 4, 2008)

mdimarco said:


> Well I would like to see some proof on the 3000 cycles.


So I showed you my proof and actual tests. Show me yours.


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## Duncan (Dec 8, 2008)

mdimarco said:


> Where did you get that info from?


It is caused by the chemical reaction - giving it a break does not help - instantaneous (or averaged over about 1 second) is what the battery "sees"


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## frodus (Apr 12, 2008)

mdimarco said:


> Your numbers are wrong, see my numerous other posts. You read your graph wrong.


Yes I did. I was actually at work rushing a project... Multitasking. Sorry. 

750 cycles... you'd still have to buy 3 lead acid packs to get what one lithium pack would give.... Hell even two lead packs would equal out to the same cost. 

Do you even drive an Ev? With lead? Pictures? Specs? 

Last week you barely knew about a controller and motor.... Now you think you're some kind of battery expert. 


More like a troll.....


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## dragonsgate (May 19, 2012)

frodus said:


> Last week you barely knew about a controller and motor.... Now you think you're some kind of battery expert.
> 
> 
> More like a troll.....


Mdimarco signed up three days ago. 28 post in that time. At this rate he will be a senor member with a shorter membership time than some junior members. As for electric cars I do not count what I have invested in mine. I count how much I drive it. My EV is not the fastest or the best but I drive it just about every day and I count how much it would have cost if I had to drive one of my gas guzzlers.


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## Logan (Sep 28, 2013)

mdimarco
You gave the numbers I did use in your first post in here. In your answer you refered to these numbers in my post as if they would be my numbers.
All I did was some arithmetic with YOUR numbers.
The rest of these posts here shows me, you are no honest player.
You declared your own numbers into mine. And after my reply you introduced facts, that you didnt use in the first post. False play! In a western movie´s poker game you´d be shot right now. 
I do not like this kind of behaviour.
Additionally I did notice - reading the other posts in here - that it is easy to get into some kind of competition and fight in here.
I do not like that too. I am off!
Somehow you lost reality. Using wrong numberrs and facts gives you these answers you got.


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## dtbaker (Jan 5, 2008)

mdimarco said:


> Geeze I've gotten everyones panties in such a twist I have to babysit my post lol.
> 
> You guys should be happy I am proving an electric car can be very cost effective for a majority of americans. All I get is nit picking and hate from electric car people nonetheless, heck I would get way more love from smart non-electric car ppl lol.



I don't think its hate...its the electric car people wanting to make sure you don't set false expectations with bad information. I think most of us here DO believe there is a financial win, in addition to the smile, or we wouldn't do it.

The summary of MY pitch is that a lead build just plain doesn't pencil out financially OR practically for realistic use. The extra weight makes the build very heavy, kills suspension, poor braking/accelleration, and almost no way to get more than 30 mile range for very long as or in the cold. The lead charge cycle is not as efficient, and even floodies are not likely to last more than 700 charge cycles, with anything over 500 being at reduced range...

LiFePO4 prismatics do pan out though.... The high points are:
- you CAN convert a reasonable utilitarian grocery-getter for $12-$15k with 40 to 50 mile daily range, which really is enough for MOST urban/suburban commute use.
- you CAN have an operating cost about 1/3, or less, of gas at today's $3/gallon
- the batteries do depreciate to $0 over a 8 to 10 year life, but the donor vehicle and electric parts hold value pretty well and the vehicle could be re-batteried, or electrics transplanted to another donor.
- you do avoid most of the expensive maintenance of a gasoline vehicle in the first 8-10 years... no oil changes, filters, fluids, water pump, serpentine belt, starter.
- *some* states do have tax credits for conversions that make it a slam dunk.... like CO gives up to $6k the year you re-register a conversion as all-electric!


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## MalibuMan (Feb 28, 2015)

I love this discussion, read every post in it. The main problem I see in your calculations and in the majority of the conversion projects (I am already on page 25 of the conversion and builds page), is the donor car. I saw a few people opting for lightweight donor cars like the Audi A2, Morgan 3-wheeler, Mazda Miata, but the majority are fairly heavy cars.

These heavy cars loose their ICE and then get a lighter electric motor and a much heavier battery pack. Raising the weight so much, that more battery capacity is needed.

Now look at the typical conversion owner (I will be exagorating slightly to make my point). For many this is not their only car, they have another non-electric) car for longer trips that their wife drives to her job or driving the kids to school. The conversion owner will use the electric car to drive to work on his own. The distance is always the same, which is great for limiting the battery pack to half a work run if you can charge at work, or the full trip if you can't.

So why don't you go for a ultra-light single-seater car as the donor? With a 500 kg donor car you think you need half the battery pack than that of a 1000 kg donor car. But a lot of batteries weigh so much, you need extra batteries to take the extra weight of the batteries into account. 

Some of the ultra-light cars I propose are: Morgan 3-wheeler, the 1960 bubble cars (Messerschmidt KR200, Heinkel Kabine, BMW Isetta) or the 2016 Elio. You could also build a cyclecart (scaled-down replica of 1920-ish race cars) that runs on electric.


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## dtbaker (Jan 5, 2008)

MalibuMan said:


> So why don't you go for a ultra-light single-seater car as the donor?


because the single seater three wheelers are either old and expensive, or new and expensive, or not compliant with DOT rules to be approved for highway travel/speeds.

those people who can get by with zero cargo space can convert motorcycles... even lighter and cheaper.

those that are efficiency minded, but need the comfort of a DOT approved vehicle car with size, weight, speed, heaters, etc. EASILY find small econobox hatchbacks like the ultimately pragmatic Geo Metro/Suzuki Swift for around $1000.

thats why


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