# Battery Amount



## Ziggythewiz (May 16, 2010)

Every car is completely different, so you'd have to measure the candidate and see how much you can fit where.


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## z_power (Dec 17, 2011)

Hm, you could fabricate 50-100 "battery dummies" from cardboard and visit junkyard, usually there're cars or shells with empty engine bays - easier to test fit if you don't have donor car yet


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## Nathan219 (May 18, 2010)

we used rigid foam insulation to simulate our batteries.


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## EVEngineeer (Apr 11, 2012)

I realize every car is different, but I was hoping to hear like an idea of what people usually can fit in a car easily. I don't know how to measure the space, because, I do not know how the other components will fit. The only parts that I know for sure I'd use is Warp9 and solution 1 or jr. I want all of the stuff under the hood, but if I need more space then, I wouldn't mind getting run flats and put more batteries in the spare tire space.

I like that idea with the cardboard boxes and foam. I got tons of both at my house.


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## WarpedOne (Jun 26, 2009)

Go look at EV-album what are typical lithium kWhs they managed to fit.

IIRC 10kWh is not a problem, 20kWh is usually doable, 30kWh is sometimes possibile, more is nearly impossible without sitting on cells.


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## Ziggythewiz (May 16, 2010)

I have ~ 26" x 28" x 10" under my hood, plus another 6.75" x 20" x 10" down in the spare tire well.


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## dladd (Jun 1, 2011)

fwiw, I had no trunk for about 1/2 of this year in my EV (i just took a long time to build a battery cover for my trunk cells) and either stuffed stuff in the back seat, or on the roof rack. Worked fine. I considered getting an enclosed roof box, but never did (too much $ for occasional use). Just bungied stuff up there.  I have a basket type carrier on my Thule load bars.

I also carry no spare tire, as the recess for the spare was cut out and replaced with the battery box (pretty typical in conversions). If I flat, I'll either call my wife to bring me the spare from the garage, or more likely just call roadside service for a tow home.


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## EVEngineeer (Apr 11, 2012)

Thanks everyone for your input


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## winzeracer (Apr 3, 2012)

I will try to say this without being offensive, so here it goes. I really think you should consider changing your name. Engineers work very hard to earn that title and it seems clear that you are not an engineer. I am all for anyone that wants to learn how to build an EV or anything they want to, but professing to be something you are not is lame.


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## Jamie EV (Oct 3, 2012)

z_power said:


> Hm, you could fabricate 50-100 "battery dummies" from cardboard and visit junkyard, usually there're cars or shells with empty engine bays - easier to test fit if you don't have donor car yet


Yup, good idea, and also those LIthiums are tiny. You can get a lot of them into a tight space like the tire well easily. I reckon you could get about 30 in there alone.


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## Ampster (Oct 6, 2012)

winzeracer said:


> I will try to say this without being offensive, so here it goes. I really think you should consider changing your name. Engineers work very hard to earn that title and it seems clear that you are not an engineer. I am all for anyone that wants to learn how to build an EV or anything they want to, but professing to be something you are not is lame.


Are you saying that a "real engineer" wouldn't ask those kind of questions? 

Did you hear the one about the constipated engineer?
He worked it out with a pencil and paper. LOL


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## Jamie EV (Oct 3, 2012)

winzeracer said:


> I will try to say this without being offensive, so here it goes. I really think you should consider changing your name. Engineers work very hard to earn that title and it seems clear that you are not an engineer. I am all for anyone that wants to learn how to build an EV or anything they want to, but professing to be something you are not is lame.


I will try to say this without being offensive, so here goes: Titles don't mean anything here. All the real ideas are done by inventors and polymaths and (autodidacts...thank you Duncan for correcting my diction. You're a prince! )

My father was no engineer and he could understand technology better than any engineer he met. Frankly, the title engineer doesn't impress me much as I know many who could not keep up with basic theory.

I'm sure there are many "real" engineers who are quite bright....most of whom don't care about a string of letters behind their names....they care about the ideas and the science.

Then there are the rest....the ones who made it through school and have the title....and now feel that a title replaces a brain.

If EngineerEVE want's to consider himself one, then that's what he is.

Anyone who doesn't like it needs to respect that. Trying to insult someone's level of know-how is elitist and lame.


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## EVEngineeer (Apr 11, 2012)

Thank you Jamie EV.


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## Jamie EV (Oct 3, 2012)

I don't take kindly to bullies.

More to your battery question, I think Lithium ions tend to solve this problem. They are really compact and I bet you could find all sorts of ways to store them. Besides, Batt boxes would probably go in once the PS pump, vacuum booster etc go in. 

You probably want easy access to all teh components regardless of batt box though. I would probably worry less about how much space you have and worry more about installing accessories devices in such a way that allows you as much contiguous space as possible...that way you aren't wiring packs together like spaghetti.


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## Ziggythewiz (May 16, 2010)

I guess I'd better drop thewiz from my name as it's not a credentialed title.

He's not even claiming to be a EE, which is a credentialed title, he's just an eee.

I used to be a credentialed Food Service Technician (burger flipper) and I've heard that called Food Service Engineer before. I'm sure most of the half-wits at GM are certified engineers; that hasn't helped them build an EV.


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## winzeracer (Apr 3, 2012)

To All,

I was not trying to be elitist, my apologies I guess the long school hours are getting to my head. I in no way want to be exclusive, as this community has been so very welcoming and helpful to me.

Sincerely,


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## EVEngineeer (Apr 11, 2012)

Apology accepted.

I was wondering would it be cheaper, less weight, and overall better, to get more 100ah cells that fit in the same space that 200ah cells would fit? I didn't do any of the math to figure out how many more 100ah cells I'd need to fit the space, to know if the power is the same either. Obviously both types are 3.2V so the 100ah cells would give me more voltage. I would need about 50 200ah cells. I see that the sinoploy 200ah cells are 7.1" x 11.1" x 2.8" weigh 12.7 and the 100ah cells are 5.6" x 8.7 x 2.4" weigh 6.9 lbs. 

If you haven't noticed I'm confused about the AH rating, because I did the math that I see on the wiki. I got about 300 ah everytime, regardless of how I put in the numbers. I see all over the evalbum and the garage of this website where people used 100, 180 and 200ah for cars and trucks and came close to my requirements. So I don't think 300 ah is correct in my math. this is where looked http://www.diyelectriccar.com/forums/showthread.php?t=11709


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## Jamie EV (Oct 3, 2012)

That is often a question I've had. I really think that it's hard to answer that one. It depends on the usable battery space of your particular vehicle, how much weight each axle can stand, the distance between packs, the distance hyou plan to go...etc. 

Tough one. To narrow it down though, you should be able to calculate amp hours per lb (or kg) easily enough?


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## Duncan (Dec 8, 2008)

winzeracer said:


> I will try to say this without being offensive, so here it goes. I really think you should consider changing your name. Engineers work very hard to earn that title and it seems clear that you are not an engineer. I am all for anyone that wants to learn how to build an EV or anything they want to, but professing to be something you are not is lame.


Hi Winzeracer,

That particular horse fled the stable long before I was born 
- in English speaking countries - in Europe somebody calling themselves an "*Ingénieur*" had better be able to back it up
Bit like being a "Doctor" in the English speaking countries

Saying that we may end up with some tightening here as the building that caused 115 deaths in the Canterbury earthquake (out of 185 total) had its construction supervised by somebody who had faked his qualification as an engineer


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## Ziggythewiz (May 16, 2010)

EVEngineeer said:


> I was wondering would it be cheaper, less weight, and overall better, to get more 100ah cells that fit in the same space that 200ah cells would fit? I didn't do any of the math to figure out how many more 100ah cells I'd need to fit the space, to know if the power is the same either. Obviously both types are 3.2V so the 100ah cells would give me more voltage. I would need about 50 200ah cells. I see that the sinoploy 200ah cells are 7.1" x 11.1" x 2.8" weigh 12.7 and the 100ah cells are 5.6" x 8.7 x 2.4" weigh 6.9 lbs.
> 
> If you haven't noticed I'm confused about the AH rating, because I did the math that I see on the wiki. I got about 300 ah everytime, regardless of how I put in the numbers. I see all over the evalbum and the garage of this website where people used 100, 180 and 200ah for cars and trucks and came close to my requirements. So I don't think 300 ah is correct in my math.


As you can see, the thickness isn't that far off, but the length and height are quite different, so it will depend on the exact dimensions of the space available. In my bug 40 AH cells take almost as much space as 100AH would because they're so much shorter.

What were your usage requirements?


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## EVEngineeer (Apr 11, 2012)

I'm not really reading an answer. Maybe someone could explain ah to me and then I can come up with an answer for my bigger question. What does ah do? I understand that more batteries equals more volts, but what does the volts do for the car verses the ah. Do I need more ah per cell or more ah overall. Am I looking to get a greater total amount of ah or volts. All I know is that I want 75+ miles range @ 70mph. If I do 45mph, I want the range to be high enough, so that I can drive the 75miles at 70mph. I don't know how high that would be, but I'm guessing it's over 100miles at 45mph.


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## major (Apr 4, 2008)

EVEngineeer said:


> I'm not really reading an answer. Maybe someone could explain ah to me and then I can come up with an answer for my bigger question. What does ah do? I understand that more batteries equals more volts, but what does the volts do for the car verses the ah. Do I need more ah per cell or more ah overall. Am I looking to get a greater total amount of ah or volts. All I know is that I want 75+ miles range @ 70mph. If I do 45mph, I want the range to be high enough, so that I can drive the 75miles at 70mph. I don't know how high that would be, but I'm guessing it's over 100miles at 45mph.


Hi EVE,

Ampere hour (Ah) is a unit of electric charge, = 3600 Coulombs (C). 

What you need to concentrate on firstly is the energy usage and amount of stored energy required. We use the units of Watt hours (Wh) or kWh to define the amount of energy. Energy is related to charge by the potential (voltage or V). So Wh = Ah * V.

Energy usage is sometimes called the efficiency of the vehicle. It is how much energy is used to move the EV for a specified distance. To normalize this, we typically use the units of Wh/mile. A typical EV may use from 200 to 400 Wh/mile. This energy usage figure depends on many things like the speed, wind direction, hills, stops and starts, driving habits, etc.

Let's jump to an example:

Say at 70 mph you determine you require 25 kW of power from the battery. If you drive for one hour at 70 mph using 25 kW of power you will have taken 25 kWh of energy from the battery and gone 70 miles.

That is 25 kWh for 70 miles or 25 kWh / 70 mi = 357 Wh/mi. That is your energy usage. 

Now you say you need 75 miles at that speed. So 357 Wh/mi * 75 miles = 26.8 kWh. You need 26.8 kWh from the battery to go 75 miles at 70 mph.

If you have a battery pack which will deliver the 25 kW of power at, say, 150 V, then you can calculate the charge needed. Take the energy and divide by the voltage. 26.8 kWh / 150 V = 178 Ah.

There you go. You need 178 Ah. That is for the conditions outlined above and is the exact amount of charge used from the battery. So you need a battery rated higher than this figure, maybe considerably higher to account for using less than 100% of the battery charge to prolong life and to accomplish your mission in adverse conditions (like a strong headwind or detours or such).

Hope that helps,

major


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## jeremyjs (Sep 22, 2010)

Think of it like a hose. AH is the volume and voltage is the pressure. Multiplying Ah x V equals the watt hours or the number of watts deliverable over an hours time. 200v and 100ah worth of batteries has the same energy potential as 100v and 200 Ah of batteries.

200v x 100ah = 20,000 watt hours or 20 Kw/h
100v x 200ah = 20,000 watt hours or 20 Kw/h


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## Jamie EV (Oct 3, 2012)

Asking which is more important, volts or amps is a lot like saying, "which is more important, the can of food or the can opener" Both are necessary if you want to eat.

VOlts times amps equals watts (power). You want more total available power in your pack....but this power is available at different rates based on the voltage of your motor and the ability of your controller to deliver it to the car. 

Higher voltage means less amperage is needed to accomplish movement with the same amount of power. If you have a motor at high voltage, you use less amps....but to move a distance at a certain speed, it's all academic because the power required is the same. 

SO the question is, what voltage are you running at, what speed are you travelling at, what is the weight of the car (sans and with batteries) and how many amps and volts can your controller deliver. 

THe answer is a function of all of these.


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## EVEngineeer (Apr 11, 2012)

Thank you for your responses. To give everyone a better idea of what I need, I need to get 70mph+ and 75+ miles range at the 70mph. I'm on flat land, not that much wind here in Florida, just lots of sun. I would use a warp 9 motor and either a solution 1 or jr.


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## Jamie EV (Oct 3, 2012)

Duncan said:


> Hi Winzeracer,
> 
> That particular horse fled the stable long before I was born
> - in English speaking countries - in Europe somebody calling themselves an "*Ingénieur*" had better be able to back it up
> ...


The guy is not applying for a job. He's not listing it on his curriculum vitae, for God's sake! 

There are many bona fide doctors and engineers guilty of malpractice too. A bona fide doctor killed my father because although accredited, he sucked.

Bona fide engineers built a bridge that collapsed after a parade tuba matched it's specific resonance frequency. 

Engineer or not, we're all people worthy of respect.

I think we should all get off our high pedestals of intellectual authority....don't you, my good man?


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## Jamie EV (Oct 3, 2012)

http://www.evconvert.com/tools/evcalc/

Don't know if this applies well to your case but I like to plug numbers and battery types into this online page. It's been around for a while but uses some equations that help with range estimations...and has a pretty slick front end.

The range you want is pretty far at that speed. Lithium could get you there. Would be costly...


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## Jamie EV (Oct 3, 2012)

In retrospect, after plugging in some numbers, and based on current Lithium energy density, I don't know how you'll get 70 miles at 75 mph within your GVWR. 

Does anyone know the peukert capacity and exponent and internal resistance of his batts?


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## EVEngineeer (Apr 11, 2012)

I know that the cost is high, but I still want to know the figures. I could see how my build would become 50k, but I am trying to make it come down to 25k. Possible? yes. probable? hell no. lol


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## EVEngineeer (Apr 11, 2012)

Jamie EV said:


> In retrospect, after plugging in some numbers, and based on current Lithium energy density, I don't know how you'll get 70 miles at 75 mph within your GVWR.
> 
> Does anyone know the peukert capacity and exponent and internal resistance of his batts?


here is a chart i found http://evolveelectrics.com/Sinopoly.html


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## Jamie EV (Oct 3, 2012)

EVEngineeer said:


> here is a chart i found http://evolveelectrics.com/Sinopoly.html


oh you're gonna make me do some formulas aren't you...ok


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## Jamie EV (Oct 3, 2012)

According to Uve Rick's calculator page and some data interpolated from the SInopoly spec sheet...


Peukert capacity is 0.5503397132132086

Peukert's exponent is 17.333538122743597


Based on the weight of a toyota Corolla (and it's gear ratio) you could expect 120 cells in a 192 volt pack to give you about 74 miles range at 70 mph for a DOD of 70%.

This is of course all from the calculator at EVCCONVERT.com....who's accuracy I have no idea of....but it gives you an idea of what kind of battery bank you'd need.

120 cells would cost you $16200 and weigh approx. 840 lbs....you might have trouble placing that many cells lol! 

That range is exceptional though...if you filled the trunk, tire well, gas tank area, front engine area with Sinopoly, it could be done...and probably under the GVWR I might add....


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## Jamie EV (Oct 3, 2012)

my peukerts might be way off. The spec sheet is crap.


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## EVEngineeer (Apr 11, 2012)

wait. (120 cells)(3.2V)=384V how do u get 192V? what ah are you using, because 100, 180, or 200 ah does not equal this (120 cells)(price per cell)=$16,200
if u r using 100ah in ur math then ($125)(120 cells)=$15,000
180ah is ($225)(120cells)=$27,000


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## WarpedOne (Jun 26, 2009)

> To give everyone a better idea of what I need, I need to get 70mph+ and 75+ miles range at the 70mph.


Here is a chart of energy usage depending on speed. Its kinda theoretical and represents Tesla Roadster that is lighter and has less airdrag than your conversion will have. So, we take these numbers as low estimation i.e. you'll need more energy than this.

The chart says it uses 300Wh/mile when traveling at constant 70mph. 75miles will thus eat up at least 300Wh/mile*75miles = 22,5kWh of energy. You cannot and must not ever completely discharge your batteries. You don't touch those last 20% of kWh, so those 22,5kWh used become 28,125kWh stored. And your car will need at least 20% more than Tesla Roadster because of higher drag, so you need about 35kWh of batteries for 75 miles at constant 70mph.

If on the other hand you ease up a bit on speed and only travel at 60mph, you'll need only about 28kWh.


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## Jamie EV (Oct 3, 2012)

scratch that...I'm sure that's not right


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## EVEngineeer (Apr 11, 2012)

I drive on roads that are 30,35,40,45,55, 65, and 70 mph speed limits, but I need to know that the car can do what I'm asking, that way I know I am capable of getting home without a problem.


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## Jamie EV (Oct 3, 2012)

EVEngineeer said:


> wait. (120 cells)(3.2V)=384V how do u get 192V? what ah are you using, because 100, 180, or 200 ah does not equal this (120 cells)(price per cell)=$16,200
> if u r using 100ah in ur math then ($125)(120 cells)=$15,000
> 180ah is ($225)(120cells)=$27,000


sorry, I was using 100 ah cells.


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## Jamie EV (Oct 3, 2012)

they said it was 135 er 100 ah cell. I wasn't even looking at 200ah....but the specs are identical for 100 ah and 200 ah in terms of reserve versus rate etc.

Frankly, they don't give you internal resistance, they don't give you minutes at specific rates of discharge...the specs are useless. You can't calculate peukerts from that.


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## Jamie EV (Oct 3, 2012)

Assuming you had a peukert exponent of 1 and a peukert capacity of 200ah (in other words no peukert effect at all! which I doubt), you would need 60 200 ah cells.....and that would get you roughly 65 miles (at 70mph) according to a Corolla LE as a model....what car are you using?

I suspect that you'd be needing closer to 90 cells to be honest...but then how many battery strings depends on the voltage you want to run....seems like 1 string is the most efficient with lithium....does anyone have any real world experience on that?


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## Ziggythewiz (May 16, 2010)

peukerts are considered negligible for LiFePO4 cells. The numbers have already been ran several times here. Just take your desired range, times 300 wh/m, divide by desired voltage, add 30% for DOD, and you have your AH needed.


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## EVEngineeer (Apr 11, 2012)

to be exact, my commute round trip that I must get is 20-45 miles at 45mph and 40 miles at 70mph. The reason for the 20-45 miles range is because I must get at least 20, but some days I do a little extra driving and I need up to another 25 miles to make it to and from my destinations. the 20 miles at 70mph is non stop driving and then to get home I need the other 20 miles at 70mph non stop driving.
That is why I have been saying 75 miles at 70mph to make it simpler and to guarantee I will make it home.


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## EVEngineeer (Apr 11, 2012)

Jamie EV said:


> they said it was 135 er 100 ah cell. I wasn't even looking at 200ah....but the specs are identical for 100 ah and 200 ah in terms of reserve versus rate etc.
> 
> Frankly, they don't give you internal resistance, they don't give you minutes at specific rates of discharge...the specs are useless. You can't calculate peukerts from that.


you get a discount the more cells you buy 1-12 cells is $135; 13-59 cells is $130; 60+ cells is $125


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## Jamie EV (Oct 3, 2012)

oops I had DOD set to 70% (which is advisable).. a STRING OF 60 200AH CELLS (PACK VOLTAGE OF 192) , if set to 80%, you get just over 70 miles at 70 mph....conversely if you drove 50, you'd go 121 miles!


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## Jamie EV (Oct 3, 2012)

EVEngineeer said:


> you get a discount the more cells you buy 1-12 cells is $135; 13-59 cells is $130; 60+ cells is $125


OOHHHH! well that's good anyways.

So yeah about 60 cells...if you're looking at 192 volts.

I'm not sure about that though....because I've heard someone say a warp 9 should not be run at that voltage. They say 144 is more ideal...but then some gear boxes won't get you up to the right speed for 70 with that rpm range...

I think it depends on your gear box a lot and your pack voltage. 

As for fitting 60 cells in your car....no problemmo.


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## Ziggythewiz (May 16, 2010)

The controller needs to match the pack. Smart controllers can control how many volts the motor sees, so that's not always a limitation.


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## EVEngineeer (Apr 11, 2012)

then a solution jr. would be the correct controller?
thanks jamie fr explaining further


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## Jamie EV (Oct 3, 2012)

Ziggythewiz said:


> peukerts are considered negligible for LiFePO4 cells. The numbers have already been ran several times here. Just take your desired range, times 300 wh/m, divide by desired voltage, add 30% for DOD, and you have your AH needed.


oh...had no idea lol...never mind.


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## Jamie EV (Oct 3, 2012)

wait 300 wh/mile at what speed?


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## Jamie EV (Oct 3, 2012)

EVEngineeer said:


> then a solution jr. would be the correct controller?
> thanks jamie fr explaining further


THank Ziggy...he set us both straight!


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## EVEngineeer (Apr 11, 2012)

oh of course i'll thank ziggy he's been a huge help to me, but was thanking you for specifically explaining further on something u didn't fully explain to me at first then I asked u to and then u did.


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## Jamie EV (Oct 3, 2012)

Does anyone know the internal resistance of the Sinopolys?


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## Ziggythewiz (May 16, 2010)

Jamie EV said:


> wait 300 wh/mile at what speed?


300 is a ballpark used for any reasonable speed. It won't be exact but it'll get you close. 

The funny thing is that the while you can cruise using much less energy at a lower speed, the average usage stays about the same for typical use because slower driving (more efficient) usually accompanies frequent stops (less efficient) so the speed generally cancels out (for sufficiently accomodating definitions of 'generally).


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## jeremyjs (Sep 22, 2010)

Ziggythewiz said:


> 300 is a ballpark used for any reasonable speed. It won't be exact but it'll get you close.
> 
> The funny thing is that the while you can cruise using much less energy at a lower speed, the average usage stays about the same for typical use because slower driving (more efficient) usually accompanies frequent stops (less efficient) so the speed generally cancels out (for sufficiently accomodating definitions of 'generally).


Isn't the weight of the car/10 a general guideline that seems to hold true, plus or minus a little bit, most of the time?


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## Ziggythewiz (May 16, 2010)

yup, so if you're light you can subract a little from that 300 estimate, if you're a fatty you add to it.


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## Jamie EV (Oct 3, 2012)

Ziggythewiz said:


> yup, so if you're light you can subract a little from that 300 estimate, if you're a fatty you add to it.


including batteries? Cause a pack of lead acids will really add to that calculation...and not in a good way.


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## Jamie EV (Oct 3, 2012)

I get an estimation for my needs (slower than EVEngineer) of about 230 watts/m to 300 w/m....but I do a lot of 50 mile/h or less driving. 

Highway would kill my setup easily.


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## Jamie EV (Oct 3, 2012)

my setup looks like this...proposed setup I mean...

http://evconvert.com/tools/evcalc/?...65:rim=14:rr=0.015:bs=0.003:kwh=0.09:miles=0:


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## Ziggythewiz (May 16, 2010)

Jamie EV said:


> including batteries? Cause a pack of lead acids will really add to that calculation...and not in a good way.


 
Absolutely. Lead should be avoided if at all possible primarily for that reason.



Jamie EV said:


> Highway would kill my setup easily.


Not necessarily. I would probably use the same doing 60 as I do averaging 25...stop signs are killer.


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## Caps18 (Jun 8, 2008)

Can you charge it anywhere during your 75 mile round trip?

The issue is that these batteries do degrade over time. And if you could drive slower, it wouldn't be a problem, but you might be forced to do that...

And add up the battery weight and try to estimate how much it will weigh.

And then you have the easy way out and look at leasing a Leaf or a Volt (or other production EV) for a few years. Once you get up to the 40+ range it is harder to justify DIY I think.


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## GizmoEV (Nov 28, 2009)

I didn't see any one mention that you can parallel LiFePO4 cells and they will act as a single cell. That is what I did to get the capacity I needed at the voltage I needed. 200Ah cells wouldn't allow me to get but 14 in my box. I went with 100Ah cells and put 40 in my battery box but did a 2p20s arrangement for my 64v nominal pack. I did a crude capacity measurement of my cells and then matched largest with smallest, next largest with next smallest, etc. until I had my pack build. The nature of LiFePO4 is that the pair will reach full together and empty together. The only thing is that it will take more than 1 connecting strap per cell to build the pack.


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## syndrella (Oct 5, 2012)

IIRC 10kWh is not a problem, 20kWh is usually doable, 30kWh is sometimes possibile, more is nearly impossible without sitting on cells.


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## evmetro (Apr 9, 2012)

Something important to know if you have lotsa range and speed in mind is that you can reduce some of your energy usage by reducing the weight of the vehicle. This is true for any vehicle, but even more important with an ev. An ev built with sound principles of physics in mind will perform better. Remember light weight, small frontal area, and aerodynamic. If you have the skills, refabricate steel stuff out of aluminum, and remove anything that does not need to be there. My recommendation if you have too much trouble with the math is to pack in as much lithium as your budget allows into your car. As far as how many 200are ah cells I use, I have 34 gbs gen 3 cells (21 kwh) packed into a metro without disturbing my interior in any way. 12 cells in a battery box fabbed to replace the gas tank, 5 under each front seat, and 12 under the hood. I might add that I was not an engineer when I started, but I feel like one now. You have all of the information of an engineer on this forum and google to get her done. Besides, half of the phd's that I have talked to seem to be Piled Higher Deeper.


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## evmetro (Apr 9, 2012)

If anybody gets you feeling self concious of your screen name here, put in 100 hours reading these forums and the wiki here. This will do more for your build than you can imagine, and would make pretty danm worthy of your name. I like it now, and I don't recommend changing it. When the going gets tough on your build, remember that you ARE an ev engineer! Best of luck on your build!


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## EVEngineeer (Apr 11, 2012)

Caps18 said:


> Can you charge it anywhere during your 75 mile round trip?
> 
> The issue is that these batteries do degrade over time. And if you could drive slower, it wouldn't be a problem, but you might be forced to do that...
> 
> ...


I might be able to charge before I go home, but I'd rather not. Time for me is an issue and I need the batteries to last long. I think the leaf is ugly, the volt is good, but it would cost 40k+ to buy one. If DIY then the cost could be 5-15k less depending how I do this.

How far does the leaf go truly. I know they say 100 miles, but isn't it more like 90 at 45 mph? also, at 70mph, how far could I go if it's already getting close to my range requirement?


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## EVEngineeer (Apr 11, 2012)

evmetro said:


> If anybody gets you feeling self concious of your screen name here, put in 100 hours reading these forums and the wiki here. This will do more for your build than you can imagine, and would make pretty danm worthy of your name. I like it now, and I don't recommend changing it. When the going gets tough on your build, remember that you ARE an ev engineer! Best of luck on your build!


thank you. I do know about losing as much weight as possible. I do not really have a budget, but I do want it to be cheaper than the volt and leaf with equal or more range than them. Also, for now, I do not have the tools to fabricate metal.


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## Caps18 (Jun 8, 2008)

EVEngineeer said:


> I might be able to charge before I go home, but I'd rather not. Time for me is an issue and I need the batteries to last long. I think the leaf is ugly, the volt is good, but it would cost 40k+ to buy one. If DIY then the cost could be 5-15k less depending how I do this.
> 
> How far does the leaf go truly. I know they say 100 miles, but isn't it more like 90 at 45 mph? also, at 70mph, how far could I go if it's already getting close to my range requirement?


There is a new Leaf coming out that might have some improvements.

You also won't get the EV tax credit if you build your own...

And the resale value is still better for a production car.

You have to really think about it, and even take some test drives in a Volt/Leaf/Focus/C-Max Energi before you start.

Plus, the batteries that you are looking for aren't going to be cheap. There is the motor, charger/controller, gauges, pumps, repairs, and a bunch of other costs too.


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## EVEngineeer (Apr 11, 2012)

http://evalbum.com/4361 I found this.

This is what I'm looking for, but I would like lots of trunk space and I don't think my car would be that light and such a low watt hour/mile


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## EVEngineeer (Apr 11, 2012)

The only car of those that I think look good, especially in blue is the volt. I don't believe there is a tax credit right now. I believe that ended. How far can the volt go? from what I read it should go much further than the leaf, because isn't the volt an EV with gas as backup?


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## evmetro (Apr 9, 2012)

The leaf has a 24kwh pack, which is about 38 200ah batteries. Probably cutting it too short of your requirements. I don't know much about the volt, but I understood that it works out better around town. Once you deplete the limited range pack, you would be hauling it at 75 mph, which is no longer sound laws of physics.


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## onegreenev (May 18, 2012)

EVEngineeer said:


> The only car of those that I think look good, especially in blue is the volt. I don't believe there is a tax credit right now. I believe that ended. How far can the volt go? from what I read it should go much further than the leaf, because isn't the volt an EV with gas as backup?


When new the Leaf will do about 75 miles at 55 mph. Right now I am getting about 72 miles with no heat or air on. The Volt in all electric mode won't even come close to the Leaf but it is a Hybrid and as such if you keep gasoline in the vehicle you can go as far as that tank of gasoline. For some the Hybrid is still the best option. Better than an ALL GASOLINE car. For me the Leaf will do but I am afraid I may have to relinquish the vehicle to my Wife when it no longer gets me to work and back. It will still be fine for the much shorter distances she has to go. She loves the Leaf too. I put on 50 miles per day commuting to work on the freeway. If I had to do that at 65 I may not make the drive by next year if the battery goes much lower. I do not like driving the car in the RED zone by any means. It is like driving your gas car when the gas light comes on. As long as I am off the RED zone I am a happy camper. Been doing well but the Guess O Meter really sucks. I am quite sure it is doing much better than the gauge leads me to believe. 

Damn trees, turtles and bars. 

I just want a nice accurate AH gauge that reads both directions.


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