Doctorbass Zero S mod to 2013 motor

[Doctorbass]

Yes guys i did it !!

I added that famous 75-7 motor that Biff ( Ryan) designed for Zero for the 2013+ model !

Actual project: 2012 SR conversion 8)

Goal : get more power and acceleration .. not top speed!

limitation: low 66V Battery voltage = limiting battery max power

You probably saw my post with the desire to add a size 6 or a 75-7 motor to my Zero... believe it or not! i'll do both !!

It is really complicated to replace all the MBB, BMS and DC-DC to reconfigure the battery voltage to 28s ( 102V nom) so i'll keep it to 66V!!

Now with that fact, i need to dig somewhere else to get more power on my 2012 S !!

Solution? better motor and higher current !!

Here is my idea:

Right now with the Stock size 4 during i'm accelerating, at about 75mph i see 30.2kW max on my cycle Analyst before it drop while continuing to 86mph. I see about 452A max on calibrated cycle analyst display during the peak of power. The controller is exploited to 105% for the current and only 64% for the voltage. BUt as you know i dont want to raise voltage for the reasons above. So for a 420A controller getting 452A would probably mean getting 690A max on the size 6 and probably 45kW.

The ZF9 battery can take that easy from what i saw. The contactor and high current wiring should be ok with gauge 1/0. Apparently the stock 425A fuse is ok with a Size 6...

Maybe one day i will just rebuild the battery to 28s and add my own BMS and will get rid of the MBB.. but from now i wanna ride my bike this summer not in 2 years of battery work lol !!! 8)

EDITED : i was wrong on some SR current calculations. Thanks Luke for the info :wink:
The S is 40kW wich mean 400A and pretty close to the max 420A power the stock size 4 can do. so the 2013-14 S is exploiting the Size 4 to about 100%.
The SR with 50kW

On my side the size 6 with 660A and 66V would give me 44kW, so it would be a little above the 2013-14 S power of 40kW!!!. not sure... but doing some basic calculations are assuming that...
The Powerband is what would make the difference... my motor will spin slower at 66V so the torque will not be sustained at speed as high as for the 2013 bike with the new 2013+ 102V battery

I can confirme that the 75-7 motor DOES FIT in the 2012 S frame. I made a foam dummy 75-7 based on the measurement i did on a 2013 S. I'll just have to add holes to fit it to the frame or add an adaptor bracket to match the different shape.

I ordered from Harlan the 25T, the 28T and the 30T so i'll be able to play with various config for finetuning the powerband.

My actual ZF9 battery internal resistance is about 8 miliohm. This mean that at 660A it should dissipate 3.4kW. let say that accelrration last for max 10 sec this is equivalent to 34kJ of energy wich is i guess probably ok if dissipated during 95% of the discharge time.. let say 1h ride from 100 to 0$ soc.... so 170W continuously average.

For the motor, the 75-7 motor should be able to manage the heat pretty well for 44kW.. otherwise i'll add forced airflow on the case fins.

The kW power i'll get at the wheel with the stock size 4 controller and that new 75-7 might be a little bit above the power i had with the motenergy due to the better torque ( 115Nm vs 66Nm) and the efficiency too.. but it is just a question of powerband.. i will shift it a little bit to the lower speed for better aceleration and i will loose torque at higher speed...but i only need to go as fast as 120km/h, it'S not a racebike!

I expect to be able to buy the Size 6 from Harlan with in about 3-4 weeks.

That will be awsome!


Doc

 

[Doctorbass]

Some pictures worth thousand words :wink:

 

[Doctorbass]

Got it to work !!!

Hey guys.. THAT IS JUST AWSOME !!!

I upgraded from 66Nm to 115Nm !! same 420A sevcon current !

It's feeling like twice the acceleration of the strock 2012 S!!!

I had to do several mod to achetve that but the motor is installed now and i had to get the rear wheel to be machined today and have the rear wheel rim threaded holes seat for the sproket to be lowered by 0.100" to get the belt aligned properly with the motor sporket. The motor 28T sproket was at the max allowable spacing so i had no choices. This make the rear sproket to be 0.100" closer to the rim.

But guess what!.. fun didn't last lomg time!!!! I just snaped the belt !!!! Yes guys the belt just broke under acceleration!! and.... i was ... just... 8km from home !!...

I had to walk 8km with the zero on my side... lol.. not a great experience!!! :lol:

I was a bit disapointed since i planned to make some great ride this weekend.. and knew that the 220 tooth belt are very rare in spare parts at our multiple zero dealers...

BUT FORTUNATLY MY LOCAL DEALER HAD ONE STOCK !!!!!


Believe me i dont want that to walk another 8km again!!!

Things learned today:

- When testing new exciting project, ALWAYS TEST GENTLY BEFORE !!!
- ALWAYS test and retest all thightened screw and belt tension
- ALSO TEST BELT ALIGNMENT during driving and see if it remain aligned under torque
- Always bring your cellphone when going for a ride for testing!
- NEVER go too far from home or garage !!!
- Have great AVAILLABLE friend that can help just in case!

Doc

 

[Doctorbass]

NO worrie guys.. this belt is really strong and is made of carbon fiber and is the same as on teh 2014 SR with 660A sevcon controller... my guess is that that belt was used and also might have suffered from multiple desinstall and reinstall process ... without untightening it before... :lol:

Well it last 8000km ! with my multiple torture

Coming next:

- investigate the real cause of the belt snap..
- correct it
- test BUT FOR VERY SHORT RIDE :lol: lesson learned lol
-enjoy the new 115Nm torque


The things i might have to correct are the belo alignment, and tightening and i will lube it as it is recommanded

Doc

 

[flathill]

Nice mod my man
All ur bass r belong to dbass

 

[liveforphysics]

The belts are extremely durable if you just ride them.

If you install them without loosening the belt, you definitely damage it. If you bend it overly tight, particularly if you bend it backwards at a tight radius, you snap the carbon fibers and it will fail.

They last an incredibly long time if belt tension stays very high and they are handled properly if removing/installing.

Also, in your first post, you incorrectly assume the SR draws only 500A battery current. It draws much more. There is essentially no power left on the table in the stock motor/controller setup.

 

[r3volved]

Very sweet ride! Well done
Curious, did the federal or provincial government offer you any rebates or perks when purchasing an EV?

 

[Ariane]

Hi Doc,

I really love, the lesson learned section of your post it's remind my old experiences with my electric motocross, stuck on trails, I connector that fails off, walking with motocross boot about 8 km, in sand trails...

Nice works man it takes allots of thing to do project like this nice accomplishments, good day, take care!

Black Arrow

 

[Doctorbass]

The belts are extremely durable if you just ride them.

If you install them without loosening the belt, you definitely damage it. If you bend it overly tight, particularly if you bend it backwards at a tight radius, you snap the carbon fibers and it will fail.

They last an incredibly long time if belt tension stays very high and they are handled properly if removing/installing.

Also, in your first post, you incorrectly assume the SR draws only 500A battery current. It draws much more. There is essentially no power left on the table in the stock motor/controller setup.

Thanks Luke, i corrected my post :wink:

I have read alot about carbon fiber belt in the tech documentation of their website... but i should have read that BEFORE... You are right sometime i as not untightening it before to remove it.. this probably damaged some fibers.

The carbon fiber cross section in the belt is so small !!! this is difficult to imagine that they can hold tensil strengh above 1000 pounds!!

the SR is about 180Nm if i remember?... with a 28T sproket, this give about

39 inch ( 1m) / about 1.5inch radius of the sproket = 26

26 x 180 = 4680

4680 / (g).... 9.81 = 477kg of tension on the belt!! = above 1000 pounds under acceleration lol...

Doc

 

[Laserman]

Sweet mod dr. Hope you are having fun with the added accel

 

[oatnet]

Nice work, Doc! Enjoy the extra boost!

-JD

 

[RLT]

Wow!

 

[liveforphysics]

If I'm not mistaken, you likely cut your 0-60mph time in HALF with these mods. I bet it feels like a rocket now.

 

[Doctorbass]

If I'm not mistaken, you likely cut your 0-60mph time in HALF with these mods. I bet it feels like a rocket now.

Totally Luke !!!

and i just replaced the belt and aligned with custom laser tool and tension it to 25 pounds ( spec say 20-30) and i just comeback from another ride.. but this time it was around my home max 2km :lol:

my previous zero-60 time was average of 8.0 sec with the Me0913 stock 2012 S motor.

In the next hour i will measure it again... but now my motor is just cooling and i'm charging the battery full.

In fact the motor temp alarm have blinked the first time today! as well i tested the motor with continuous acceleration and deceleration duuring hald an hour to ensure everything is ok for myt little 400km trip tomorrow =)

Next thing will be to find the right adjustment for the field weakening parameters... cause right now my motor seem to cut at about 4000rpm but on the DVT log i saw it to peak to 6000rpm briefly and go back to 4000 with some oscillation.

in the video you can clarely hear the motor speed ramp up and then it drop suddeenly with a strange sound.. i guess it's the field weakening that is not properly set... after all i have the motor parameter for a battery of 102V but i'm using it at 66V.. i just wonfder of the rpm map might need some readjustment to have the filed weakening to start at the proper rpm...

here is the video of that problem: [youtube]X5b4ESAl78o[/youtube]

 

[Doctorbass]

ACCELERATION TEST !

OK now the belt is repaired! and aligned with my custom laser alignment tool =)

I tested it during 100km with torture on the throttle!! this evening at full acceleration and deceleration

and the belt is perfect, no sign of wear!

Here is a video i made to show the acceleration 8)

btw previous acceleration was 8 sec woth the stock 2012 motor and not it is at 6.4sec and can be improoved by just toping off the torque curve in the controller. it is actually set to 66Nm at 0kmh and 115Nm at about 100kmh and it could start directly at 115Nm !

[youtube]JD-W3kok4h4[/youtube]

Doc

 

[Arlo1]

Cool Doc. Is that with a size 4 ?

 

[r3volved]

Is the CA providing a more accurate readout than the actual dash? Looks like they're out of sync by 5-10kph. Which one do you focus on?

 

[Doctorbass]

Cool Doc. Is that with a size 4 ?

Yes it's with the stock size 4. Next upgrade will be size 6

Doc

 

[Doctorbass]

Is the CA providing a more accurate readout than the actual dash? Looks like they're out of sync by 5-10kph. Which one do you focus on?

YES.. The C-A is quicker and more accurate Than the Zero speedo. It seem that the one on the zero is not responding really quick... it's like it have a smooting filter on teh response wich make it slower to react and display the actual speed.

Doc

 

[Arlo1]

I think luke said the 75-5 will make more torque per phase amp then a 75-7. The 75-5 maxes out at ~70-75 ft/bs with a size 4 so I would say you are making less then 70 ft/lbs you also need more voltage to get the torque curve to flatten out. The back emf will cause the torque curve to fall quite fast. mine is also set to 115 nm I tried to play with that but that seemed to be the best setting. It does not mean it makes 115nm its a setting above the actual max of the motor by a bit to ensue you are getting the full amount of phase amps the controller can push.

 

[liveforphysics]

I think luke said the 75-5 will make more torque per phase amp then a 75-7. The 75-5 maxes out at ~70-75 ft/bs with a size 4 so I would say you are making less then 70 ft/lbs you also need more voltage to get the torque curve to flatten out. The back emf will cause the torque curve to fall quite fast. mine is also set to 115 nm I tried to play with that but that seemed to be the best setting. It does not mean it makes 115nm its a setting above the actual max of the motor by a bit to ensue you are getting the full amount of phase amps the controller can push.

Indeed, due to the additional turns on the more narrow motor, it makes more motor torque per amp of phase current. The bigger one has substantially higher continuous torque however.

 

[querlenker]

Did anyone test the -5 above the 420 phase amps? Luke..

 

[Doctorbass]

Update 30 june 2013:

Ok i just comeback from my 450km ride this weekend. I went close to Lac Megantic close to the US border where we have some familly. I would say that the Wh per km is really similar than before with the stock motenergy Me0913.

On the road i am also able to reach about 125km/h with the 75-7, the stock 66V 2012 battery and the stock 28T and 132T sproket.

Problem is that at high speed ( i mean over 90kmh) i get the motor cut out !!! Yes the motor just cut and if i set back the throttle a bit lower the power comeback.. but it cut again if i maintain that speed above 90kmh.. It act just like the motor would have some overtemp and the controller would protect it.. but i dont see any temp alarm on the dash!...
If i keep lower than 90kmh, let say 80-85kmh, it dont cut and it seem to become colder because if i go back to 90+ kmh it last more time... until it cut again... and sometime i see the temp alarm but not every time.. just let say 20% of the time!... that's strange!!

The power draw at that speed ( i see on the C-A) seem to be reallly similar to the power i was seeing with the previous motor.. so it does not seem that the motor draw more power than it should.. but it cut !

The cutback is instant, it's like i loose power.. than i wait a bit and i can get the power back after 1-2 or 3 sec when i twist the throttle repeatly to (feel when it comeback)

It happen at any state of charge. It hapenned after a given period of run. It dont happen in the first 10-15 minutes, it just happen after 20-25+ minutes of continuous run at 90+kmh..

That's why i feel it'S like a overtemp but the motor is hot to touch but not bruning my hand...

I just wonder if it is something to have with the Field weakening and some parameters that affect it... i think that the field weakening parameters might be still set for the 2013 S with the 102V battery... so the torque vs voltage curve and others parameters might be not optimized for my lower voltage battery of 66V...

My torque curve is still set for 66Nm at 0rpm and linearely raise to 115.4Nm at 4000rpm etc..

Doc

 

[querlenker]

I don't want to give some wrong advice as I don't know your exactly setup, but I had some trouble with the thermal cutback. Imagine the Sevcon not only measures the actual temperature via the temperature sensor, it calculates an temperature that "should" be more realistic. The temperature sensor is slow, it chances it's resistance not as fast as the windings really heat up. So the Sevcon takes for example the current and some other factors in count and calculates its own estaminet temperature for the actual situation. As far as my experience is, this can be more than 40 degree more than the sensor itself would be. From the case to the sensor you can add easily another 20-30 degree while running.. I would recommend you to check your thermal settings. Maybe the 2012 setup is there different too. I run for example much different values, as the motor is modificated, with stock zero setup I had big problems..

Also I would change a bit your torque curve, it should be pretty hard to deliver 115Nm at 4k rpm. Mine is different, it's high from the beginning and than I reduce from about 3k rpm on..

One thing you should check to be save too, is the controller temperature..

I think Biff will be the best to ask, if you don't find the fault yourself.

 

[John in CR]

Problem is that at high speed ( i mean over 90kmh) i get the motor cut out !!!

I hope you meant MPH, not kmh. I was going to challenge you to a podcast race, but if 90kph is "high speed" for you, it simply wouldn't be fair, since I call 90 slightly over half speed.

I hope you get the shut down issue sorted out.