[Franky.EV]

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.

 

[spdas]

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

 

[Franky.EV]

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

 

[spdas]

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

 

[Franky.EV]

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.)

 

[CTR01]

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.

 

[Franky.EV]

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.

 

[lonestarrpm]

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

 

[Ravishankar]

Where can I get this file ?

 

[GizmoEV]

Where can I get this file ?

A couple of posts above yours.

 

[Franky.EV]

Hi, This is the unprotected version

 

[lkcl]

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.

 

[lkcl]

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".

 

[Franky.EV]

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.

 

[tomofreno]

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.

 

[gor]

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?

 

[tomofreno]

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.

 

[Franky.EV]

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.

 

[Jordanie]

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!

 

[lkcl]

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).

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!

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.