# Yes Another EV Calculator



## Franky.EV (Feb 27, 2010)

I propose a new version of this EV calculator.
The problem I noticed in all EV calculators on the WEB, is that they predict, mileage and other stuff at cruising speed.

As you know, you can eat more energy while you are accelerating to reach the desired speed :

- If you accelerate very slowly, your mileage is low for a longer perdiod of time.
- If you floor the pedal, your mileage is high for a shorter period of time.

I try to address this in this new version, so :
- the parameter "Trottle" tell what your cruising speed will be.
- the parameter "Accel" tell how fast you want to reach the cruising speed.

In the yellow cells you know :
- the cruising speed, depending on "Throttle"

First column
- the energy consumed to go to that speed
- the distance to reach that speed
- the mileage (mean) while getting to that speed
- the time to reach the cruising speed

Second column
- the remaining energy, once you are at the desired speed
- the range
- the mileage
- the time remaining if you ride at the cruising speed

Third column
total energy distance and time, global mileage

You can change any parameters in blue text cells
This calculaor run only with OpenOffice (Apache). LibreOffice is buggy and nobody correct bugs when you ask !!!

The "EV" sheet is protected, to avoid messing up things, but has no password.


The graph may have to axis : "Time" or "Speed"
- When "Time" is applied, the Yaec shows only the "best gears"
- When "Speed" is applied, you have the choice to show the "best gears", or the "full gears", you will notice full gears give different times than best gear as you are suppose to start in the designed gear and hence in may be longer.

You can disable a gear, to simulate a start from 2nd or 3rd gear.
You can change the Cell rate, to see the effect on the Torque and Power curve in "Motor" graph.
You can change cell topology, to get best range or max speed.
You can change grade from -30% to +30%.

Enjoy.

Take into account :
- max motor voltage
- max motor amp
- max battery pack voltage
- max battery pack amp
- C rating setting
- max battery power deliverable
- grade
- Gear
- inertia from equivalent mass of rotating parts
- Speed / Time axis


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## TheSGC (Nov 15, 2007)

Franky.EV said:


> Another EV Calculator, in oooBasic


I tried it but I can't open the file- it says it has been locked and password protected.


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## esoneson (Sep 1, 2008)

I'm using OpenOffice 3.1 on Linux Fedora 12 and have no problem with it.

Eric


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## dexion (Aug 22, 2009)

good with me as well (open office 3.1)


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## Franky.EV (Feb 27, 2010)

Some views of my EV Calculator


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## TX_Dj (Jul 25, 2008)

Are you sure the file got updated in your edit? 

Excel still tells me:
Cannot open 'Franky EV Calculator.ods': This file has been protected with a password and cannot be opened.

I'll try later with OO, but I downloaded it a machine that doesn't have that installed.


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## Franky.EV (Feb 27, 2010)

Yes TX DJ

To be sure, I've downloaded it and checked. It has document protection removed, but still has a sheet protection (necessary to avoid messing it all up)

It runs well on OpenOffice (I have version 3.2).

I'm not sure you can run it with Excel, as it makes great use of oooBasic macros.


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## octagondd (Jan 27, 2010)

How do I change the pack topology to say 45S - 1P? Also, if the pack voltage is set real low, shouldn't the Speed be limited?


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## octagondd (Jan 27, 2010)

I figured out the 45 cell thing. My macros weren't enabled.


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## Franky.EV (Feb 27, 2010)

Nice you found it. I've preparared a screenshot, just in case, for other people.


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## Franky.EV (Feb 27, 2010)

The formula I use to compute acceleration time is too optimistic, as it consider acceleration constant. Does anyone as a good formula ?

It should be an integration of :

dt = m v dv / (Pmax - ½ ρ Ca A v3 -( μ m g + m g sinα ) v)


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## maxvtol (Nov 11, 2009)

Franky.EV said:


> The formula I use to compute acceleration time is too optimistic, as it consider acceleration constant. Does anyone as a good formula ?
> 
> It should be an integration of :
> 
> dt = m v dv / (Pmax - ½ ρ Ca A v3 -( μ m g + m g sinα ) v)


Acceleration is definitely not constant. And unless you're only using direct drive you'll need to consider gearing. 

I used F=m*(v1-v2)/t or t=m*(v1-v2)/F, the F being what the motor can deliver to the tire patch, less F required at speed (and inclination in your calculations). I used 5mph increments, looks like accuracy should be within 5%.

You really should include what force the tires can deliver to the pavement, since it looks like a friction coefficient of 1 for dry pavement is pretty close to all you'll get. I'm toying with this in my spreadsheet now. 

Download the spreadsheet in my signature, you should be able to figure out everything.


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## Franky.EV (Feb 27, 2010)

maxvtol : I've read the entire thread and downloaded your spreadsheet, but I'm to figure out what are the formulas as I only understand metric.


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## maxvtol (Nov 11, 2009)

Franky.EV said:


> maxvtol : I've read the entire thread and downloaded your spreadsheet, but I'm to figure out what are the formulas as I only understand metric.


I haven't done a detail check of the units in your formula, but at first glance it looks ok. It's just for average power over a increment in velocity. You can't use the maximum power of the motor for this, you'll have to use the average power over that increment in velocity, and to find this you'll have to use a motor chart to find the power at your start velocity and end velocity and average that power. You'll need the rpm for this, that's why you'll need the gearing ratios. Then you can just add the times for each velocity increment for an ET. 

My formulas are in the cells, mostly under the acceration chart, although I'm using F instead of the P/v in your equation, but same thing. My spreadsheet is more taylored to finding maximum acceleration, but let me know what you're trying to do and I'll help any way I can.


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## Franky.EV (Feb 27, 2010)

I've done some work to implement gearbox in another sheet (Motors).

All is not perfect, still need some work to do.

But you can choose gear ratio, change gear, or take rid of one or more gear, and see what happens.

Obviously, You'll better have a big powerfull motor and only one reduction gear.


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## Franky.EV (Feb 27, 2010)

Job finished, and updated V2.

All things in a signle sheet, and more coherency among diffrents formulas.

Take into account, motor torque, gear.

EDIT : BUG correction, graphic has sometime incorrect size
some simplification

EDIT : Added shift time


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## Franky.EV (Feb 27, 2010)

My ev calcultor now takes care of : power, C rating, DOD, gearbox ratios, shift time, grade.

I've updated the file in the the first post, and make some cleaning.


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## EVfun (Mar 14, 2010)

My EV acceleration calculator...

Determine the power to weight ratio, using estimates for actual voltage and motor efficiency. Find an ICE car with that power to weight ratio and use its numbers. Expect to do a little better in the real world because electric motors have wider power band compared to most ICEs. Follow up with construction and driving to see for yourself how good your calculator is  

Yes, that means that most golf cart battery powered EVs end up performing like 36hp or 40 hp Beetles.


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## Franky.EV (Feb 27, 2010)

Change mileage to wh/km and some optimization.

Update in first post


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## maxvtol (Nov 11, 2009)

A few suggestions.

I can only download the zipped file, then open it (only opens as read only), I have to do a "Save As" then use that file to get it to work. If that is the way it's supposed to work, I would put that instruction in post 1 where you download it. Other instructions on how to use in the spreadsheet itself would be useful, either on a separate page or on the flyovers. Somehow marking where the dropdowns are would be nice. 

Label the x and y axis on the graphs with the units. 

There's no way to adjust motor voltage or amperage which affects performance, this is done with the controller settings on my spreadsheet. To give a realistic performance, that should be included, at least on DC motors. On AC, I'm not to sure how it would be done, but if it requires a certain voltage or amperage battery pack, you could default a battery setting. And I'm curious as to how you're getting your motor charts. 

Put the acceleration in G's. In toying with my spreadsheet, if you have close to a 50/50 weight distribution, you'll probably only get roughly 0.5 G's acceleration (more for RWD, less for FWD). If the acceleration shows more than 0.5 G's for a particular motor, it's probably not realistic (at least on a 50/50 weight distribution with similar tires on front as on back).


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## Franky.EV (Feb 27, 2010)

Hello Max,

The file is not read-only, is't just zipped, I thought is was the best extension permited by the forum.

OK for the labels, big mistake i'll correct soon.

As this spreadsheet is just a simulation program, I need formulas and "boundary conditions" to program the effect of changing the nominal voltage.

For now, I only use datas I've found in available torque curves, with only 3 points : 2 for the flat torque portion, and 1 for the max rpm. Maybe I can add some more columns to take care of voltage ranges.

I've found these datas sufficient to emulate a torque and power curve, with a correlation function. 

I'll check your spreadsheet to understand how you deal with acceleration and weight distribution , I've not seen anything about that before. I suppose the simulation I give is for an ideal 50/50 weight distribution, but with correct datas entered it give 4.0s for 0-100km/h and 190km/h max for the Tesla. Not far from the real numbers.

Thank's for your sugestions.


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## roflwaffle (Sep 9, 2008)

Franky.EV said:


> The formula I use to compute acceleration time is too optimistic, as it consider acceleration constant. Does anyone as a good formula ?
> 
> It should be an integration of :
> 
> dt = m v dv / (Pmax - ½ ρ Ca A v3 -( μ m g + m g sinα ) v)


If you don't already have it here's the formula for acceleration. It would be more accurate to have the calculator interpolate a polynomial given some torque values and insert that as a an actual power curve instead of just a constant torque curve.


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## Franky.EV (Feb 27, 2010)

Quite a long time I've updated this EV calculator, it's now based upon torque curves.


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## roflwaffle (Sep 9, 2008)

Looks good. I probably should have checked it to see if the acceleration portion was working before I posted. If my guesstimate is correct the only thing you could add is a hard limit to your top speed based on motor speed versus gearing. Given the initial values in your script the car shouldn't be able to go above ~160km/hr given the ~7300rpm limit of the HVH250.


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## Franky.EV (Feb 27, 2010)

Hello roflwaffle, if you set the rpm limit to 7300 in the Motors rpm table, with a 1575 kg car, a 3.70:1 reduction gear ratio (direct drive), and other defaut parameters, the speed limit is 160 km/h.

But I have the Remy HVH motor spec sheet that set max rpm to 10600.

Remy HVH 250

Anyway, max speed will depend of numerous factors. I don't know what car you plan to convert.


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## roflwaffle (Sep 9, 2008)

In that case it looks like your chart for motor speed is being cut off at row 73 for some reason. Nice calculator btw. Have you thought about incorporating motor efficiency curves into it? That way someone could see the difference between motor efficiency at various speeds/loads wrt gearing.


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## Franky.EV (Feb 27, 2010)

In fact, I use the table on the right side, only to display the graph, the actual calculations are done via the left side of the table, where I conceptualize the motor torque curve with only two points.

Rought approximation, but every thing is approximate here !

By the way you can change the graph resolution by changing the "blue" parameter " Δrpm 
By default it's set to 150, try 200 or 250...

I don't plan to have motor efficiency, or motor performance based on the voltage at the moment, one day maybe...

Regards


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## Bellistner (Dec 12, 2010)

Great spreadsheet! Did my head in a little bit when I first opened it, but all good.

Some additions that would come in handy for Australian and New Zealand users, if you feel like adding them in a future update:

Gearbox:

*As fitted to Holden Gemini (TX, 1976)*

M20 4-speed
1st: 3.51:1
2nd: 2.17:1
3rd: 1.42:1
4th: 1.00:1




*As fitted to Holden Gemini (TG, 1983)*
M75 5-speed
1st: 3.51:1
2nd: 2.17:1
3rd: 1.42:1
4th: 1.00:1
5th: 0.86:1

M40 3-speed Trimatic
1st: 2.31:1
2nd: 1.46:1
3rd: 1.00:1




*As fitted to Holden Commodore (VB, 1978)*

4 speed MC6 2.85 and 3.3 L6 Manual Transmission
1st: 3.50:1
2nd: 2.02:1
3rd: 1.41:1
4th: 1.00:1


4 speed Torquemaster M20 2.85 and 3.3 L6 Manual Transmission
1st: 3.05:1
2nd: 2.19:1
3rd: 1.15:1
4th: 1.00:1


4 speed M20 4.2 V8 Manual Transmission
1st: 3.05:1
2nd: 2.19:1
3rd: 1.15:1
4th: 1.00:1


4 speed M21 5.0 V8 Manual Transmission
1st: 2.54:1
2nd: 1.83:1
3rd: 1.38:1
4th: 1.00:1


3 speed TriMatic M40 3.3 L6 and 4.2 V8 Automatic Transmission
1st: 2.31:1
2nd: 1.46:1
3rd: 1.00:1


3 speed TurboHydramatic 350 M41 5.0 V8 Automatic Transmission
1st: 2.48:1
2nd: 1.48:1
3rd: 1.00:1




*As fitted to Holden Commodore (VN, 1988)*

5 speed Manual M78 V6 Transmission
1st: 3.25:1
2nd: 1.99:1
3rd: 1.29:1
4th: 1.000:1
5th: 0.72:1


5 speed Manual M78 V8 Transmission
1st: 2.95:1
2nd: 1.94:1
3rd: 1.34:1
4th: 1.00:1
5th: 0.73:1


MD8 4 speed Turbohydramatic 700 Automatic Transmission
1st: 3.06:1
2nd: 1.62:1
3rd: 1.00:1
4th: 0.70:1




*As fitted to Ford Falcon (XD, 1979)*

Manual (Six, 3 speed Borg Warner)
1st: 2.95:1
2nd: 1.69:1
3rd: 1.00:1


Manual (Six and 4.9 litre V8, 4 speed)
1st: 3.06:1
2nd: 1.84:1
3rd: 1.32:1


Manual (5.8 litre V8, 4 speed)
1st: 2.36:1
2nd: 1.78:1
3rd: 1.27:1
4th: 1.00:1


Manual (5.8 litre V8, 4 speed)
1st: 2.46:1
2nd: 1.78:1
3rd: 1.27:1
4th: 1.00:1


Automatic (3.3 and 4.1 litre Six; Borg Warner 35-3)
1st: 2.39:1
2nd: 1.45:1
3rd: 1.00:1


Automatic (3.3 and 4.1 litre Six, 4.9 litre V8; C4-3)
1st: 2.46:1
2nd: 1.46:1
3rd: 1.00:1


Automatic (5.8 litre V8; Ford FMX-3)
1st: 2.40:1
2nd: 1.47:1
3rd: 1.00:1




*As fitted to Ford Falcon (EB GT, 1992)*

BTR 5 speed overdrive Manual
1st: 3.35:1
2nd: 1.99:1
3rd: 1.33:1
4th: 1.00:1
5th: 0.72:1


Type: BTR 4 speed overdrive lock up torque convertor
1st: 2.39:1
2nd: 1.45:1
3rd: 1.00:1
4th: 0.68:1



Once you've got a dozen or so gearboxes listed, maybe put them on a seperate sheet as well? In fact, you could probably push the Motors 'boxout' onto a seperate sheet as well, and leave the dropdown box on the main sheet. If you move the Motors dropdown to the top right, and shift the 'boxout' with the Gearbox dropdown in it to the right of screen as well, and that would let you widen the columns for Power, Uptime, Range, etc.

*Cd (according to Wikipedia):*
1995 (XG) Ford Falcon:0.31
1998 (EA) Ford Falcon:0.295
1998 (VT) Holden Commodore: 0.31.

Could you add some RPM/Torque specs for Kostovs motors as well (like the 17R 144V, Dual 17R 144V, R20 192V)? Their graphs do my head in.


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## Bellistner (Dec 12, 2010)

Spent some time with this spreadsheet this morning. Very, very handy. I'd previously conservatively estimated a conversion to get 300wH/km at highway speeds. You spreadsheet is suggesting I'll be 'sipping amps' at a miserly 147wH/km and less, which doubles my range, so I'm somewhat suspicious that I've done something wrong.

Specs:
~1000 kilo car after conversion. 900 kilo ICE-standard weight, ~150kg engine, ~50kg ICE ancillaries, add back in a 200kg battery pack, M75 gearbox.
65 100AH Sky Energy cells, 65P1S, 70% DoD (15kWh pack).
0.3C[sub]d[/sub].
0.5s shift time.
Impulse 9.

This gives me a range of 262km @ 30kmh and 59wH/km, 206km @ 60kmh, 75wH/km, and 119km @100kmh, 129wH/km. The Range is so far in excess and the Mileage so far below my estimates that I'm sure I've done something wrong to the spreadsheet!

EDIT: just figured out the 15kWh was _useable_ capacity, not total capacity. With 46*100AH @100% DoD, my range is now 'only' 122km @ 100kmh...?

If the figures the spreadsheet are giving me are correct, I can almost halve the size of the battery pack (smaller batteries, but keep the voltage up), cutting perhaps a third off the cost of the conversion.


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## Franky.EV (Feb 27, 2010)

Hello Bellistner, glad you appreciate this ev calculator, and I'll try to make the changes you've asked for.

Concerning your project, my calculator is based only on math formulas. I think these formulas are good, as I could verify, for example, that I have an error of only 0,1 sec in acceleration for the TESLA Roadster.

But real world may differ, as there are a lot of parameters. Check controller, motor and transmission efficiencies, are they not too optimistic ?

The 14,5 kWh useable energy with DOD 70% and 65 ThundySky 100Ah is correct. DOD 100% will kill your batteries.

And don't forget all numbers are metric, as I'm french !!!

But 1000 Kg after conversion is not so heavy, have you check equivalent conversion in this forum garage ?


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## Bellistner (Dec 12, 2010)

Franky.EV said:


> DOD 100% will kill your batteries.


Indeed. I only use it to find the absolute max range a pack would provide. Using 70% DoD seems to maximise the battery cycles and lifetime.



> And don't forget all numbers are metric, as I'm french !!!


I'm from Australia, so all good, since we also use your superior system 



> But 1000 Kg after conversion is not so heavy, have you check equivalent conversion in this forum garage ?


Not yet. Still going through the forums at the moment.


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## Bellistner (Dec 12, 2010)

Did some more tinkering with this today. It's quite addictive sitting here playing with various options. I'd been using 300wH/km as a very conservative estimate of useage, figuring that when it came time to put the EV on the road, anything under that was 'free'. Most home-brew EV's seem to be targeting 300wH/mi, but 300wH/mi is actually only 188wH/km.

Americans seem to love things like a S-10 'truck', which I understand is an easy vehicle to convert, plus it have carrying capacity to boot, so that's understandable. If I convert a small, lightweight, somewhat aerodynamic car like a Daewoo Lanos or Holden Gemini, and your calculator shows it using about ~80wH/km @ 60 and ~140wH/km @100km/h, that seems to be in the right ballpark, which tells me I haven't broken your spreadsheet. Yet. 

I also re-entered data for the Headway cells, and it worked this time. I must have done something wrong previously. FWIW, data for them is as follows:

Headway 38120S
10 AH
3.2V
330g
5 C
Headway 40152S
15 AH
3.2 V
480g
10C
Sky Energy/CALB SE60AHA
60 AH
3.2 V
2340g
4 C


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## Franky.EV (Feb 27, 2010)

In this thread and this link you can see that for a little car, it's perfectly doable to have a 110wh/km consumption (real life numbers)

Try to check if this mightyboy conversion can compare with yours.

Regards.


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## Franky.EV (Feb 27, 2010)

Hi Bellistner, I've made some modifications to my EV calculator. I also changed the name .

For the gearboxes, I need the final ratio (differential ratio) other way the formula won't work.

I still need to improve this spreadsheet, but you can see the work in progress.

Regards.


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## Bellistner (Dec 12, 2010)

Cheers Franky. Layout looks good.

EDIT: Two small glitches in the latest version. Pack topology tops out at 60S1P, and the charts don't change (only 'Motor' will display).
Final Drive for *TX and TG Geminis* is 3.90:1

Final drive for the *VB Commodore* is a hodge-podge:

2.85 L6 4 speed MC6: 3.36:1
2.85 L6 4 speed M20: 3.36:1
3.30 L6 4 speed MC6/M20: 3.08:1 / 3.36:1
3.30 L6 TriMatic M40: 2.78:1 / 3.08:1 / 3.36:1 
4.2 V8 TriMatic M40: 2.78:1 / 3.08:1 / 3.36:1 
4.2 V8 4 speed M20: 3.08:1
5.0 V8 TurboHydramatic M41: 2.60:1 / 3.08:1
5.0 V8 4 speed M21: 3.08:1 / 3.36:1

*VN Commodore* is slightly better:

V6: 3.08:1
V8: 3.08:1
Commodore SS: 3.45:1
Statesman and Caprice: 3.08:1

*XD Falcon*:

3.3 litre Six manual and auto: 2.92:1
4.1 litre Six manual and auto: 2.92:1
4.9 litre V8 manual and auto: 2.92:1 
5.8 litre V8 manual: 2.92:1
5.8 litre automatic: 2.77:1
3.3 litre Alloy Head from June 1980 2.77:1

*EB/ED Falcon*: 3.27:1 and 3.23:1

Way too many choices there. No wonder manufacturers have narrowed the options for new cars. For the spreadsheet, I'd be inclined to pick a max of three combinations each of gearbox and diff for the Commodores and Falcons and leave it at that.


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## Franky.EV (Feb 27, 2010)

Not sure I can match this with your other post, do you have all this data in a spreadsheet ?

Concerning the Kostovs motor, I haven't find any torque curve, in their web site.

The torque curve is defined by at least two points :
- base rpm
- max rpm

You can add them, if you have this data.

Thanks


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## Bellistner (Dec 12, 2010)

I'm taking the opportunity to add a whole bunch of other data that may be useful to somebody. I'll post it up in a few days, hopefully.


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## Franky.EV (Feb 27, 2010)

I've got some approximate Kostov data from their website and I've put them in the spreadsheet.

But I'm already working on a new version in which I could check the max voltage and max amp of the motor, compared to the max voltage and max amp of the battery pack.

Work in progress.


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## Bellistner (Dec 12, 2010)

Looks good.

Atattched is my modified spreadsheet (it's actually a .rar, but renamed to .zip so the forum software would take it). I've added info (highlighted in Orange) to the 'Batteries', 'Drag Data', and 'Driveline' sheets, and moved the motor listing to a seperate sheet (but obviously has no effect on the macros). Hope the data is helpful.


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## Franky.EV (Feb 27, 2010)

OK, I look to modify the spreadsheet, but I go for a trip to Paris next week, I'll see that later.


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## Franky.EV (Feb 27, 2010)

Back from Paris for 15 days and I've been working on the spreadsheet.

Now I take into account :
- max motor voltage
- max motor amp
- max battery pack voltage
- max battery pack amp
- C rating setting

UI has been modified to have every thing in logical blocks

That's still a simulation, based upon what I've understand about EV. But i'm not a specialist. Just doing that for the fun.

Use at your own risk


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## gor (Nov 25, 2009)

hi, Franky
what the reason - it didn't show values?

does anyone have such problem?
thank you


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## Franky.EV (Feb 27, 2010)

I'm using OOOCalc 3.2.0 at home and OOOCalc 3.2.1 at work.

I don't understand the problem, as you should'nt have any value in the cell "Power" for "v=0". I have deleted the formula in this cell, as you can see in the image in my post.

Try to download again, and check your Open Office version.

Regards.


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## Franky.EV (Feb 27, 2010)

I've noticed I don't check validity of the "coeff of rolling resistance", and if you enter a text value for exemple, you have the problem, but it also mess up the corresponding calculated force "Fr".

I will post a newer version with all data entry checks verified.


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## gor (Nov 25, 2009)

Franky.EV said:


> I'm using OOOCalc 3.2.0 at home and OOOCalc 3.2.1 at work.
> 
> I don't understand the problem, as you should'nt have any value in the cell "Power" for "v=0". I have deleted the formula in this cell, as you can see in the image in my post.
> 
> ...


hmm - same thing in other computer and with all earlier versions of calc
ooo 3.2.1; build 9502; oo update says - up to date
can be bug in macros, file path name,etc? what is your build?


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## Franky.EV (Feb 27, 2010)

Hey Gor, I got it !!!

You have to enable macros in "Tools - Option - Security".


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## gor (Nov 25, 2009)

Franky.EV said:


> Hey Gor, I got it !!!
> 
> You have to enable macros in "Tools - Option - Security".


 yea - perfect, it works! thanks, Franky : )))))

menu: tools-options - macro security- mid or low

in mid. settings it would ask to enable macros, in low - run all
thanks again


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## Franky.EV (Feb 27, 2010)

I think the simulation is correct when pack_amp >= Motor_Max_Amp.

If you set the C rating two low or choose a battery with low amperage then motor_power can be more than pack_power.

Something is wrong.

Still working on it.


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## Franky.EV (Feb 27, 2010)

New version soon, with better handle of max pack power.


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## Franky.EV (Feb 27, 2010)

As promised, new version taking care of battery pack max deliverable power.

I now see another problem . Uptime, Range and Mileage calculations, are based on minimal power demand. They don't match with the acceleration time which uses max power.

Looking for some graph to show that out.

Comments welcome.


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## Franky.EV (Feb 27, 2010)

Some new works :
- Bug corrected : macros won't initialize when spreadsheet has been previously saved with activesheet <> "EV"
- Better handling of "low amp torque"
- added : sport mode : you floor the pedal to reach max speed and hope everything goes well (no ESP yet)

See new graphs in the first post.


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## spdas (Nov 28, 2009)

Franky.EV said:


> Some new works :
> - Bug corrected : macros won't initialize when spreadsheet has been previously saved with activesheet <> "EV"
> - Better handling of "low amp torque"
> - added : sport mode : you floor the pedal to reach max speed and hope everything goes well (no ABS yet)
> ...


Aloha, I tried to D/L the openoffice Program to make use of the this neat Calculator. (from ooodocs.org) and managed to get a virus. Any recommended sites to get the OO program? thanks
Francis


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## Amberwolf (May 29, 2009)

http://openoffice.org

The original and best site, should be safe. If there's a virus there, I'd be surprised.


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## Bellistner (Dec 12, 2010)

What Amberwolf said. If you've got a Torrent program, use that instead of regular downloading, as it saves some of their bandwidth.


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## golden boy (May 31, 2010)

Thanks very much for sharing.

Is there a way to changing the battery parameters? 

It mentions the cells are protected.


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## Franky.EV (Feb 27, 2010)

Sorry, Golden Boy, battery sheet was protected by error.

File corrected in posts #1 and #51.


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## ZX-E (Aug 31, 2009)

Wow, this is an extensive spreadsheet! Hats off to you Franky .


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## spdas (Nov 28, 2009)

I got a good virus-free version of OO, but the spreadsheet contents have a lot of ### and values for motors 

Cannot change from AC55 in the ev sheet.

chart in EV is also filled with #value! in the uptime to 3rd gear column

What am I doing wrong?

thanks
Francis


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## Franky.EV (Feb 27, 2010)

Thanks' a lot ZX-E

Spdas, you have to enable macros.


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## spdas (Nov 28, 2009)

Franky.EV said:


> Thanks' a lot ZX-E
> 
> Spdas, you have to enable macros.


Ok thanks that works now. BTW is CALB not 3.2 v and not 3.4v as listed? thanks
Francis


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## Franky.EV (Feb 27, 2010)

I've seen on a the Web that CALB SKY Energy batteries are all listed 3.4V, except the 400Ah model which is 3.2V.

Maybe there is an error in my file, please feel free to correct.


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## spdas (Nov 28, 2009)

Franky.EV said:


> I've seen on a the Web that CALB SKY Energy batteries are all listed 3.4V, except the 400Ah model which is 3.2V.
> 
> Maybe there is an error in my file, please feel free to correct.



I cannot as it is a protected cell.
Francis


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## Franky.EV (Feb 27, 2010)

Spads, I've uploaded a non protected version (see post 56). Download the spreadsheet again.


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## spdas (Nov 28, 2009)

Franky.EV said:


> Spads, I've uploaded a non protected version (see post 56). Download the spreadsheet again.


I do not see a file in post 56 and posts #1 and #51 are protected
Francis


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## Franky.EV (Feb 27, 2010)

I come with another version of my OpenOffice EV Calculator.

I removed some parameters and hard coded some parts, so the program is faster and simpler to use.

I also set the default Δv to 1km/h, so the curves are more precise, but this give some minor differences in the "EV" sheet (Δv = 10km/h).

I added a "Mode" parameter to set different curves :

Cruise / Speed
Sport / Speed
Cruise+Sport / Speed
Cruise / Time
Sport / Time
Cruise+Sport / Time

Only "Cruise/speed" and "Sport/time" have real meaning :

- Cuise mode : the car has reach the desired speed and has no more acceleration, so you observe what is happening as this speed.

- Sport mode : you floor the pedal to reach maximum speed in minimum time, and you observe what is happening during this time.

But I thought interesting to compare the Cruise and Speed mode, you can think of the Cruise mode as an "extreme Cool" mode : you try to reach a desired speed in the "maximum" time, in fact in cruise mode this time is infinite.

The curves help to understand why you litterally suck the battery if you have a sport driving mode, the mileage is in an order of magnitude of that of cruise mode at the beginning, and tends to equal the cruise numbers while the power increases.

I don't set RPM, Torque, Time, and Speed in cruise mode, as they are computed in Sport mode only.

(This speadsheet run on OpenOffice Cacl, with macros enabled.)


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## CTR01 (Apr 19, 2011)

This probably doesn't help any or is already known...but the calculator can be viewed via Google Docs (after being uploaded of course). Just too bad can't use all the features without having to use OO.


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## Franky.EV (Feb 27, 2010)

I come with a new version. In fact, it's more a proof of concept.

I didn't like the "cruise/sport" comparison in the precedent version, as I've said it doesn't has real meaning.

So I propose to vary the percentage of "sport driving mode" so that when this percentage is "0%" it's like "cruise" mode.

To do that I use oooBasic controls, but they are quite buggy and slow.

So when you launch the spreadsheet, allow some time for initialization before cliking on any control.

I also give a mode with individual curve for each gear.

So you can set :
- percentage of sport driving mode
- percentage of C_Rating
- percentage of DOD
- grade
- Global / Gear mode
- Speed / Time axis

Enjoy.

Know bug : When you set "Speed" Graph with "speed" axis, or "Time" Graph with "time" axis you get a line in global mode as expected, but curves in gear mode, because the axis refer to the global mode (each gear as his own axis). This is kind of weird.

PS : I plan to rewrite everything in a VisualBasic like IDE (SharpDevelop), I can get anything more from oooBasic.


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## lonestarrpm (Aug 18, 2011)

Is there a non-protected version.

I'd like to play with my conversion (Porsche Boxster S)

however
many of the features I need to edit are protected pages.

thanks,

Mike


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## Ravishankar (Jan 26, 2009)

Where can I get this file ?


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## GizmoEV (Nov 28, 2009)

Ravishankar said:


> Where can I get this file ?


A couple of posts above yours.


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## Franky.EV (Feb 27, 2010)

Hi, This is the unprotected version


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## lkcl (Sep 16, 2011)

I've done a conversion of the maths behind this spreadsheet, into python. then, as i am the lead developer of the pyjamas project http://pyjs.org it would be remiss of me not to create a Desktop / Web 2.0 GUI application out of the simulator.

i've released the source code under the GNU Affero (AGPLv3+) License Version 3+ http://www.gnu.org/licenses/agpl.html

then i've also pre-compiled the application and you can therefore run it in any modern web browser, here:

http://lkcl.net/ev/vehicle_simulator/output/Simulator.html

this is in support of the Ultra-efficient EV Hybrid Project, http://lkcl.net/ev but the source code, available at http://lkcl.net/ev/vehicle_simulator, can be used for any vehicle. if you are not familiar with Free Software Licenses *please read the AGPLv3+* before using, modifying or contributing to the source code.


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## lkcl (Sep 16, 2011)

ok there's a bug related to drivetrain efficiency.

the logic required is this:

def power_for_speed(vehicle, state):
gp = gravity_for_gradient(vehicle, state)
ad = aerodynamic_drag(vehicle, state)
rr = rolling_resistance(vehicle, state)
p = (ad+rr) / vehicle.drivetrain_efficiency
if gp > 0:
p += gp / vehicle.drivetrain_efficiency # up hill, goes against
else:
p += gp * vehicle.drivetrain_efficiency # down hill, works in favour
state.power_required = p
return p


the logic as shown in the modified spreadsheet is *not* correct, it assumes that if you go downhill the efficiency is reversed: it's not. the efficiency is *only* reversed on the downhill portion (gravity) - you still have drag and rolling resistance "as standard".


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## Franky.EV (Feb 27, 2010)

Ickl

Thanks for your post, I've seen something was wrong when you go downhill with my calculator, I'll check the solution you give and post a correction, but, I'm on a linux system with LibreOffice now, and my spreadsheet don't work anymore, pb in interpretation of formulas. I have to correct this before.

Regards.


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## tomofreno (Mar 3, 2009)

Thought you might be interested in this:
http://hpwizard.com/rotational-inertia.html

I failed to take account of inertia of rotating parts when estimating acceleration from the difference in available wheel torque and required torque to move the vehicle at a given speed - the net torque available to accelerate the vehicle - because I thought it wouldn't be that significant. It does indeed have a significant effect in the lower gears, fairly big effect in first. I corrected for it by using the simpler equation for equivalent mass near the bottom of the article, which is also given on page 99 in Bob Brant's book: Build Your Own Electric Car, using the symbol C sub i. I just divided the net torque by C sub i. The estimate is still off a bit, about 14 seconds, versus 16 seconds measured using a GPS to record vehicle speed versus time.


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## gor (Nov 25, 2009)

tomofreno said:


> Thought you might be interested in this:
> http://hpwizard.com/rotational-inertia.html
> 
> I failed to take account of inertia of rotating parts when estimating acceleration from the difference in available wheel torque and required torque to move the vehicle at a given speed - the net torque available to accelerate the vehicle - because I thought it wouldn't be that significant. It does indeed have a significant effect in the lower gears, fairly big effect in first. I corrected for it by using the simpler equation for equivalent mass near the bottom of the article, which is also given on page 99 in Bob Brant's book: Build Your Own Electric Car, using the symbol C sub i. I just divided the net torque by C sub i. The estimate is still off a bit, about 14 seconds, versus 16 seconds measured using a GPS to record vehicle speed versus time.


 pretty awesome work, thanks, T
14 vs 16 - which calculations you mean?


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## tomofreno (Mar 3, 2009)

> pretty awesome work, thanks, T
> 14 vs 16 - which calculations you mean?


 Gor, I didn't do the work, I just found it on the net, and used the results in a calculation of acceleration. I calculated about 14 seconds zero to 60 mph time for my car using the results, but measure 16 seconds. I just used the simple equation at the bottom of the article for estimating the effect of rotational inertia, as I don't know the mass and radius of my flywheel and didn't care to estimate those parameters for the half shafts, wheels, and tires. I might get a more accurate estimate if I did, since the simple equation is just a rough estimate for all vehicles which scales with vehicle weight, likely based on rear wheel drive. But then each calculation is vehicle-specific. The simple equation can be used in a spreadsheet for any vehicle since only gear ratio and vehicle weight must be specified. From Brant's book: F = C sub i * W * a, where C sub i is the mass factor, W is vehicle weight in pounds, and a is acceleration in mph/sec. C sub i = 1 + 0.04 + 0.0025*g*g, where g is the overall gear ratio - the simple equation near the bottom of the net article.


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## Franky.EV (Feb 27, 2010)

As I've switch to Linux Ubuntu, and Ubuntu has switch from OpenOffice to LibreOffice, I noticed YAEC spreadsheet, doesn't work anymore.

So I diggued into the spreadsheet to see what was wrong, I found LibreOffice has another interpretation than OpenOffice for empty cell et null cell (equal zero).

Doing so, I change some stuffs in the spreadsheet to correct things I don't like.

The graph may have to axis : "Time" or "Speed"
- When "Time" is applied, the Yaec shows only the "best gears"
- When "Speed" is applied, you have the choice to show the "best gears", or the "full gears", you will notice full gears give different times than best gear as you are suppose to start in the designed gear and hence in may be longer.

You can change any value that appears in blue cell or control.
You can disable a gear, to simulate a start from 2nd or 3rd gear.
You can change the Cell rate, to see the effect on the Torque and Power curve in "Motor" graph.
You can change cell topology, to get best range or max speed.
You can change grade from -30% to +30% (a bug in OpenOffice does't allow negative percent in control !).
The "Sport" field allows you to apply full trottle and see what happen : you go faster, suck the battery, and get very high mileage !
"Cruise mode" = "Sport = 0%" that is very very coll driving.

Enjoy.

Run in OpenOffice 3.3 or LibreOffice 3.3, doesn't run in LibreOffice 3.4 or 3.5 as they have changed their naming convention, I'll correct this for next version.

See file in first post.


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## Jordanie (Aug 28, 2012)

Hi all!

I'm working on a conceptual project as summer student and my task is to estimate how the required battery for a 100 tone electrical transporter(for nuclear components within ITER fusion reactor: (http://www.sciencedirect.com/science/article/pii/S0920379610005624)

As an input information I know the the x,y cordinates of the vechicle and possible velocity profiles for (dV between the x,y cordinates of the trajectory - all in exell table format)

I have done simple exell calulator but not sure if the results I get are relaistic. Do you know if I can use any of the upper mentioned tools for calibrating my estimation. My spread sheet is applied to the tread, please have a look. Here at fusion for energy the IT policy is tite so it is a bit of a pain to instal any software such as open office!

Please let me know, what you think, at the moment I get for:

130meters; 100tone vechicle, Crr = 0.01, Vmean=0.1659 m/s Total time = 1160seconds, and you can see the axeleration profile within the sheet, I get I would require about --> 1839 W of Power(rms) and 30kg of (lead acid batteries).

If I ignore friction forces, I get that the energy required just for the change of momentum for this velocity profile and 100Tone vechicle is only 2.35kg

Do you have any sugestions of how I can calibrate my battery estimator?

Thank you allot!


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## lkcl (Sep 16, 2011)

Jordanie said:


> Hi all!
> 
> 130meters; 100tone vechicle, Crr = 0.01, Vmean=0.1659 m/s Total time = 1160seconds, and you can see the axeleration profile within the sheet, I get I would require about --> 1839 W of Power(rms) and 30kg of (lead acid batteries).
> 
> ...


i don't use excel (it's proprietary, and i'm a free software developer) so you'll have to put the calculations into a non-proprietary format if you want my help.

however you might like to try this:

http://lkcl.net/ev/vehicle_simulator/output/Simulator.html

you should be able to experiment with that, putting in appropriate numbers. the full source code is available: PLEASE NOTE that the license is the "Affero GPL v3.0+" - so you WILL need to make publicly available ALL AND ANY modifications that you make to that source code.

for example numbers: i put in:


weight: 100000 (in kg)
Cd: 0.3
surface area: 10 (in sq.m)
Cr: 0.015 (0.01 i think you'll find is too low.)
max and avail power: 500000 (in watts)
max torque: 500 (this is in Nm)
what that gives is a 0-56.4mph time of 497 seconds, taking almost 10km to achieve that speed, at which point it's using all of the 500kW specified as the maximum available for the vehicle. actually, it was using pretty much all of that 500kW by about the 5.5km mark.


but, anyway: what you can do, if you run that for yourself, is grab the output cut/paste style and then use excel or python to turn the power used on each step into a Joules figure (J=Power in watts x time in seconds).


from that you will be able to calculate whether the battery selected has enough energy (in Joules) to get this monster vehicle up to the appropriate speed and stay there.

other things you need to know: gear-change time in this simulator is set at about 0.5 seconds, and you'll need to examine (and change it in) the source code, yourself [don't ask me to change it for you: that would be doing your work for you. unless you're offering me a paid-for programming contract. that's how free software works].

for a big truck like this, which would usually have something like a 19-speed primary gearbox as well a 2 or even 4-speed rear axle, that is NOT enough. nowhere near enough. you should really allow at least 1.5 seconds for gear changes on big trucks, esp. 100 tonne monsters like this one.

i did a vehicle simulator for Detroit Diesel 19 years ago (SpecManager) so i studied these things for about 18 months. it was... fascinating in a mind-boggling kind of way 

l.


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## Jordanie (Aug 28, 2012)

Hello, lkcl

The transport pallet is going to be compleatly electric - DC mottors no gearboxes. (have uploaded a speck)

Here I have applied the open office version. On the right is the input data for a particular trajectory and the step to step vechicle velocity profile. On the right is my estimation of the required Wh and estimated battery mass.

I'm trying to predict the size of the Li-Accid battery required for this trajectory completion. One way that I try is by using equation that I derived for the battery mass (you can see it in the sheet) - with oversizing getting about 37 kg(li-acid) of battery for moving 100Tones over 130 Meters for 807 Seconds with the shown highly variable velocity/acceleration profile.

On the other hand when I look at the required Power(RMS) in Wh for this trajectory i get about 9626 Wh rated battery required which if I devide it by 40wh/kg energy density given for Li-accid batteries I get: 9626/40 = 240 kg 

Big difference!? 

Do you have any suggestions on the way I'm aproaching the problem??

Thank you!

Jordanie


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## lkcl (Sep 16, 2011)

ok. you really need to look at the VehicleEfficiencies spreadsheet. i'm not going to do your work for you (unless paid) - but some basics you can gain from here:

http://www.howstuffworks.com/tire4.htm

so if the Cr is 0.015 and the vehicle is 100,000kg then the drag force alone is 100000*0.015 = 1500.

at 55mph therefore you'd need 484HP *just* to overcome rolling resistance - that's 361kW!

however.... 130 metres taking 809 seconds is an average of 0.16m/s which is roughly 0.5mph - certainly not 55mph!

... a leetle different 

so actually, rolling resistance losses at 0.5mph is only 3.28kW, which is not bad. at 0.6mph it'd be 3.94kW.

wind resistance at 0.5mph is going to be negligable but you should take into account *windspeed* losses. i.e. if the transporter is moving the payload and there's a 30mph (about 12m/sec) headwind, you *need* to take that into account, due to the massive size (front surface area) which i'm guessing is about 10-15sqm or thereabouts.

also, gravity (inclines) are going to be an absolute bitch, here. even the slightest incline - even a 0.5% grade - will eat power. you should check that the conditions are perfectly level (flat).

l.


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## PStechPaul (May 1, 2012)

I used my online EVcalculator with your figures (100,000 kg for 100 tons?), and I got 9803 N force and energy of 1625 W. For acceleration I used 0.0000286 m/s/s assuming the nominal speed will be reached at 1/2 the total transport time. It's written in JavaScript so you can make changes or add to it if you wish. If you do, please post the changes and I might add them to my version.


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## johntrhodes81 (Aug 8, 2010)

Franky,

I tried to add additional gearboxes but they don't show up. Is that only something you can do?

Thanks,
John

I was trying to add the GM 6L45/ 6L50 which is a trans for RWD cars.


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## agazdziak (Sep 24, 2012)

As a heads up, there is a typo for the CALB-SE130AHA and CALB-SE180AHA batteries - their AH values are swapped in one of the sheets.

Edit: John, to get my parts to show up I had to add them to the appropriate sheet, save the document, then close it and re-open it.

One question: how do I generate separate curves for peak and continuous motor values? I'm trying to add a new motor in there and I got a graph for the continuous but haven't figured out how to get it to show multiple curves (like it does for the AC90 motor).


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## Franky.EV (Feb 27, 2010)

I propose a new version of this EV calculator.
The problem I noticed in all EV calculators on the WEB, is that they predict, mileage and other stuff at cruising speed.

As you know, you can eat more energy while you are accelerating to reach the desired speed :

- If you accelerate very slowly, your mileage is low for a longer perdiod of time.
- If you floor the pedal, your mileage is high for a shorter period of time.

I try to address this in this new version, so :
- the parameter "Trottle" tell what your cruising speed will be.
- the parameter "Accel" tell how fast you want to reach the cruising speed.

In the yellow cells you know :
- the cruising speed, depending on "Throttle"

second column
- the energy consumed to go to that speed
- the distance to reach that speed
- the mileage (mean) while getting to that speed
- the time to reach the cruising speed

third column
- the remaining energy, once you are at the desired speed
- the range
- the mileage
- the time remaining if you ride at the cruising speed

You can change any parameters in blue text cells
This calculaor run only with OpenOffice (Apache). LibreOffice is buggy and nobody correct bugs when you ask !!!

The "EV" sheet is protected, to avoid messing up things, but has no password.

Please download spreadsheet from first post.

Enjoy.


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## tomofreno (Mar 3, 2009)

Looks nice. Are you accounting for equivalent mass of rotating parts in your acceleration calculations? It can be significant. For example the flywheel in my car adds about 630 lb equivalent mass in first gear. It is about 180 lb in second gear, and unimportant in higher gears.


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## Franky.EV (Feb 27, 2010)

I don't take equivalent mass of rotating parts into account. I don't know how to compute the moment of inertia of the different rotating parts.

Is there a method to approximate equivalent mass ?


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## Franky.EV (Feb 27, 2010)

I've found this formula :

Me = M ( 1 + 0.04 + 0.0025 G² )

Me : effective mass (mass of vehicle + equivalent mass of rotating parts)
M : mass of vehicule
G : total gear ratio

I gonna to figure out how to put this in the spreadsheet.

Thank's for your remark.


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## tomofreno (Mar 3, 2009)

Franky.EV said:


> I've found this formula :
> 
> Me = M ( 1 + 0.04 + 0.0025 G² )
> 
> ...



If you call the quantity in parentheses in your above expression the mass factor, C sub i, then you can likely work out that the "available acceleration" (if you floor it to give it the max torque available at that motor rpm, the "available torque") at a given vehicle speed is:


available acceleration = (3600/5280)(Available torque – required torque)*2*12*32.2/(Ci *EV weight*tire diameter)

which is equal tractive effort/(vehicle mass + equivalent mass), or F/(m + me)


"required torque" is the motor torque required to move the car at a given speed, and "available acceleration" is the max acceleration rate possible at that motor rpm, overall gearing g, and current vehicle speed. You can calculate Ci for each overall gear ratio then use the appropriate one for calculation of available acceleration (aa) in a given gear. When aa in gear n-1 becomes about equal to aa in gear n, it is time to shift.


Units conversions in the eq: 3600 sec per hr, 5280 ft per mile, 12 inches per foot, tire diam/2 = tire radius. Let me know if I made an error.
Edit: You will of course need the torque-speed curve for the motor to get the available torque at given motor rpm and vehicle speed.


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## Franky.EV (Feb 27, 2010)

I'll check this but as you know I'm french and I use metric system ...

I have to convert the formula.

I correct my previous post : "Me" is the effective mass (mass of vehicle + equivalent mass of rotating parts).

By the way I've found a very interesting WEB site on the subject :

http://hpwizard.com/index.html


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## tomofreno (Mar 3, 2009)

Franky.EV said:


> I'll check this but as you know I'm french and I use metric system ...
> 
> I have to convert the formula.
> 
> ...


 No, I didn't know that. Would have given it this way then:

available acceleration (kmph/sec) = (3600/1000)(Available torque – required torque)*2/(Ci *EV mass*tire diameter)

Tire diameter in meter, EV mass in kg, torque in N-m and available acceleration in kmph/sec, or change in vehicle speed (in km per hr) per second. Conversion factors: hour = 3600 sec, km = 1000 m, tire radius = tire diameter/2.

Yeah, the HP Wizard is a good reference. The equation for the Ci factor is near the end, given as the simpler approach. It is the only way I see to include this effect in a spreadsheet without requiring users to input a bunch of specific details on their vehicle which they likely won't know.


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## tomofreno (Mar 3, 2009)

There is also this that I wrote up a while back after reading HP Wizard:


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## Franky.EV (Feb 27, 2010)

Good reading.

I take the formula from hpwizard and put in the spreadsheet.
Was very easy, as mass is present in only one expression.

As you say Tomofreno, you can see the effect in the first gear, where the car stays longer before needing to shift. Time, distance to accelerate, and energy consumed are longer at final speed.

Thank's.


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## Franky.EV (Feb 27, 2010)

Tomofreno,

I've update my speadsheet, but now the result (0-100mk/h in 3.9s) is incorrect for the Tesla Roadster.

Obviously, the equivalent mass formula from hpwizard doesn't work for vehicle with no flywheel, and no complicated gearbox : much gain for the true EV car.

I'll will add a parameter to take that into account.


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## tomofreno (Mar 3, 2009)

Franky.EV said:


> Tomofreno,
> 
> I've update my speadsheet, but now the result (0-100mk/h in 3.9s) is incorrect for the Tesla Roadster.
> 
> ...


 Yes, there are complications like that when you try to do a general spreadsheet for many types of vehicle. 

Using the Ci parameter is about as much as you can simplify it though I think. For what it is worth, after I included the equivalent mass in the calculations for my car I estimated 14.9 seconds for 0 to 60 mph plus two shift times. If I estimate 0.5 sec per shift I get 15.9 seconds for 0 to 60. I measured the 0 to 60 mph time by data logging speed versus time with a gps, and got 16 seconds. So for my car it happened to agree very well. I expect it will vary quite a bit with vehicle model, but it is better than not including it for vehicles with a flywheel/clutch assembly.


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## Franky.EV (Feb 27, 2010)

OK, I've found a more generic formula for equivalent masses from : http://www.thecartech.com/subjects/auto_eng/car_performance_formulas.htm
I'll do something with that, depending of FWD, RWD, front or rear motor mount.

Inertia Resistance (_IR_):









where:
_IR_ = inertia resistance [N] 
_m_ = car mass + equivalent mass of rotating parts [kg]
_a_ = car acceleration [m/s2], (from 0 to 100 km/h in: 6 s (4.63 m/s2), 18 s (1.543 m/s2))
_mcar_ = car mass [kg]
_meq_ = equivalent mass of rotating parts [kg]
= [ _Iw (1/rw)2 + Ip __hf (if /rw)2 + Ie __ht (if ig / rw)2_] 
where:
_Iw_ = polar moment of inertia of wheels and axles ≈ 2.7 [kg m2]
_Ip_ = polar moment of inertia of propeller shaft ≈ 0.05 [kg m2]
_Ie_ = polar moment of inertia of engine ≈ 0.2 [kg/m2] + polar moment of inertia of flywheel and clutch ≈ 0.5 [kg m2]
_hf_ = mechanical efficiency of final drive 
_ht_ = mechanical efficiency of transmission system (hg x hf)
_ig_ = gearbox reduction ratio [ig1 or ig2 or ………….]
_if_ = final drive reduction ratio 
_rw_ = tire radius [m]

* ( + ), (+) with the car in *acceleration*. {tractive resistance}
(-) with the car in *deceleration. *{tractive effort}


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## tomofreno (Mar 3, 2009)

Now you are back to estimating the moments of inertia for all the rotating parts for each model car you consider. Also, this has included transmission and drive train efficiencies in the equiv mass, so have to ensure they aren't being used anywhere else in your calculations in a way that "double counts" them. Plus, who knows what those efficiencies are? I think the best you can do is a ball park number, same for most vehicles. But its your time, so have fun.


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## Franky.EV (Feb 27, 2010)

I propose an option for the calculation of mass factor as you can see in the picture. The numbers are taken from : http://www.thecartech.com/subjects/auto_eng/car_performance_formulas.htm

but you can modified them, if they don't suit you.

See the spreadsheet file in the first post, easier to maintain versions.

For Tesla Roadster I just uncheck "Shaft" and "Flywheel".

The result is now correct for the 0-100km/h : 4.02 s this gives 3.9 for 0-60 mph !


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## tomofreno (Mar 3, 2009)

Franky.EV said:


> I propose an option for the calculation of mass factor as you can see in the picture. The numbers are taken from : http://www.thecartech.com/subjects/auto_eng/car_performance_formulas.htm
> 
> but you can modified them, if the don't suit you.
> 
> ...


 Sounds good. You might add some explanatory comments on that section of the spreadsheet for those who aren't familiar with equivalent mass, so they can figure out what options to select for their vehicle. That was quick!


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## Franky.EV (Feb 27, 2010)

Some calculations were weird with slow rate of acceleration, and give enormous time to reach the desire speed due to the fact that acceleration 0 is reach in infinite time, I removed such values.

I also take into account empty battery, to limit range.

Little change to stats.

File update in first post.


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## ryanwalexander (Aug 31, 2013)

This calculator looks great! I was going to make my own. Maybe I'll try to contribute to this one too.

However, when I open it in OpenOffice, I'm getting #NAME? in almost all the cells and the graph doesn't work.

I've been trying to figure out what's causing it but I haven't been able to!


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## Franky.EV (Feb 27, 2010)

Hello Ryan. Due to new realeases of Open office, this calculator only run with Ooo 3.4.1 (or LibreOffice 3.0)

If you have this version (or previous to 3.4.1) be sure to enable macros. 

Regards.


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## ryanwalexander (Aug 31, 2013)

Thank you, downloading now!


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## dedlast (Aug 17, 2013)

Franky.EV said:


> Hello Ryan. Due to new realeases of Open office, this calculator only run with Ooo 3.4.1 (or LibreOffice 3.0)
> 
> If you have this version (or previous to 3.4.1) be sure to enable macros.
> 
> Regards.


Franky, I saw you had reported this issue as a bug at Open Office. Do you know if they ever got it squashed? I had to roll back to 3.4 to use the calculator and it has been very helpful.

Bill


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## Franky.EV (Feb 27, 2010)

Hi Bill,

The bug is reported as _Bug_ #122840, and is now marked as VERIFIED FIXED.

So I'm waiting for the new release of OpenOffice, 4.1 or something.

The guys at ApacheOpenOffice.org were very responsive and very fast to correct things.

I've also signaled the bug at LibreOffice, and they treat me as though I didn't know how to use their product. 

That's why I switched back to OpenOffice (before the same bug appears !)

So wait and se the next version of OpenOffice.

Regards.


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## dedlast (Aug 17, 2013)

Good news. I'll be keeping my eyes open, then.

Bill


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## PStechPaul (May 1, 2012)

I just tried this calculator and I am very impressed. JFF I added a 100 Ah 12V lead-acid battery and used it for a 1P 20S pack with a K11" 192V motor with a 96-01 Civic EX transmission and a 4% grade. But the label of the graph shows HPEVS AC50 and 0% grade. I am using Open Office 3.30.

It seems that the motor list has duplicate entries, some with two and some with three. I was able to add my own 2HP motor to the list, but it is a simple list and not derived from the names in the battery data table. So it should be easy to delete the superfluous items.

The battery power density is labeled kWh/kg and should be Wh/kg.

I fixed the motor list and the updated file can be obtained at:
http://enginuitysystems.com/files/YAEC_20130927.ods

I left in the lead-acid battery and the 2HP motor, but all the other changes are corrections.


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## Franky.EV (Feb 27, 2010)

Hello Bill,

Apache has just release version 4.0.1, and every thing run fine. I thank the guys at Apache OpenOffice, far more professionnel than LibreOffice ones.


Paul,

That's long time since I have'nt look inside this spreadsheet, but I think the motor table is'nt dynamic, you have to exit OpenOffice and open again the speadsheet after a motor modification.

I've done that because of the way I managed the list before. I have to change that.

Regards.


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## dedlast (Aug 17, 2013)

Franky.EV said:


> Hello Bill,
> 
> Apache has just release version 4.0.1, and every thing run fine. I thank the guys at Apache OpenOffice, far more professionnel than LibreOffice ones.


Thank you, sir. 



> Paul,
> 
> That's long time since I have'nt look inside this spreadsheet, but I think the motor table is'nt dynamic, you have to exit OpenOffice and open again the speadsheet after a motor modification.
> 
> ...


I can verify that. I have added a few things like a transmission and a motor and discovered that a restart was needed to see the changes. Still, a nice bit of work and very helpful.

Bill


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## PStechPaul (May 1, 2012)

I just loaded it again and now it seems to work OK. I might not have had macros enabled previously. I can change the motor characteristics and they are updated automatically. The only thing I have problems with is the small 2 HP motor I added which results in divide by zero in the maximum speed section, but that is probably outside the range for which this calculator was intended. It's a very nice tool!


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## MasterCATZ (Sep 28, 2013)

just a few extra's that could be added into it 

Direct Drive ( for gear box ) 
AWD 
Option to add extra motors into equation ie 1,2,4


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## aggiemarine07 (Nov 26, 2013)

Ok so im definitely not a math genius like you are because this spreadsheet is nothing short of impressive; thank you for the time and effort of this sheet.

I do have one question though, I am assuming that you can use this sheet to roughly figure out how much battery power, etc you need in order to have your vehicle run effectively, correct?

My suggestion, can you make a simple post explaining how to fill out this spreadsheet for the idiots, such as myself, who didnt do so well in business math in college? 

I know what my vehicles weight would be approximately (1250 kg), the minimum round-trip (80 km), and top speed (120 KmH) and I assuming this sheet can help me figure out how many batteries I need to get these minimums, right? Thanks!


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## Franky.EV (Feb 27, 2010)

Hello Aggiemarine,

Thanks for your comment. To use the spreadsheet, basically, you need to input value only in all blue-text cells in the first sheet.

First basic parameters :







These parameters are very conservative ones, no need to modify them in first approach. If you know the Cd value and front area of you donnor car, you can input these values, I give some sample in the sheet "Drag Data". I suppose the efficiency of the entire drive train is 83%, change efficiency of controler or gearbox if you think it's to high or to low.

Then the mass of your vehicle :







No comment

Then the motor :







If your motor is in the list it's OK, if it's not you have to put it in the "Motors" sheet : name, max rpm with constant torque, max torque, max rpm, troque at max rpm, max amp, max volt and estimated efficiency.

Then the gear box :







Same as motor, if it's there in the list it's ok, if not, add it in the sheet "Gearboxes".

Battery Pack :







Choose a cell type in the list, if's it's not then, add it in the sheet "Battery". You have to set how many cells you put in serie (100 in the exemple) and in parralel (1 in this example). Try first to match the voltage of your motor, here the voltage of the battery pack is 320V, far more than that of the motor wich is 72V, that's why the voltage is red (the higher voltage the higher speed). Then try to match the max amp your motor can absorb : you have to choose an appropriate cell type, here pack amparage is only 177A and the motor can absorb 335A (The higher amp, the quicker).

You can now choose the graph and data you want to see (power, range, etc.) :







Throttle tell how fast you want to go, and Accel how quick you press the pedal : 100% is very sporty.

These yellow cells give you a summary of principal datas :








I hope you will be able to use the spreadsheet with these explanations. I'm trying to do something easier, but time is missing.

Regards.


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## aggiemarine07 (Nov 26, 2013)

Thanks! that's really helps, about the sheet though Im using libreoffice 4.1 and the summary stats state #VALUE, do you know why it displays the results as #VALUE?


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## Franky.EV (Feb 27, 2010)

In fact, there is a bug in LibreOffice, I've filed the bug to OpenOffice and LibreOffice. OpenOffice has correct it, and LIbreoffice has not.

The screenshots in my previous post are from Apache OpenOffice 4.0.1.

PS : you need to enable macros to run the spreadsheet.

Cheers.


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## Max Clark (Apr 10, 2012)

Very cool application. You put a lot of work into this calculator and it shows.
I had to download open office to get it to work...thanks again!
Ford Focus almost finished...AC 50, 300 Ah batteries.


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## Max Clark (Apr 10, 2012)

Could you explain the time option. How is that depicted? Thanks


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## Franky.EV (Feb 27, 2010)

Thanks Max. The time option change the x-axis of the graph to "time" versus "speed".


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## beshan (Dec 17, 2013)

Great Calculator! I am having trouble trying to match this calculator to the actual Tesla Roadster. I put in all of the data correctly (I think), but the acceleration time to 100kmph is almost double of what Tesla Roadster is. Is it possible for you to upload a version that matches the Roadster ? This will help create a baseline to make progress. Thanks much !


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## Franky.EV (Feb 27, 2010)

Hello Beshan,

You can try this parameters :

- Gearbox and motor of type : "Tesla Roadster"

- Battery : Kokam-SLPB120255255 : 101S and 3P, this give correct voltage and amperage

- vehicle mass : 747 kg this give a total mass of 1310 with passenger, luggage and battery

Regards.


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## victor.miranda (Jul 23, 2018)

Hi everyone!

First of all, thanks @Franky.EV for putting together this awesone spreadsheet.

Has anyone tried to use it with a wheel/hub motor?

And, how to take into account a direct drive on the gear setup?

Thanks in advance.

Cheers,
Victor


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## nickC29 (Jul 18, 2018)

This is really impressive stuff! The work you put into this really shows. Need to play around with it to understand if further. Think it will take some experimentation haha


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## gwayne (Dec 9, 2017)

I can open it in Excel but it looks like the macros are broken. If you ever make an excel version, please let me know. Thanks. gw


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