[Franky.EV]

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.

 

[roflwaffle]

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.

 

[Franky.EV]

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

 

[roflwaffle]

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.

 

[Franky.EV]

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.

 

[roflwaffle]

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.

 

[Franky.EV]

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

 

[Bellistner]

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.

 

[Bellistner]

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.

 

[Franky.EV]

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 ?

 

[Bellistner]

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.

 

[Bellistner]

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

 

[Franky.EV]

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.

 

[Franky.EV]

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.

 

[Bellistner]

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.

 

[Franky.EV]

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

 

[Bellistner]

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.

 

[Franky.EV]

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.

 

[Bellistner]

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.

 

[Franky.EV]

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