Doctorbass 2WD ADAPTTO / NYX / MXUS 32kW 105 pounds

[Stielz]

Awesome! now to see how it goes on 400A phase current

For some reason I thought you were putting the faster 3T mxus on the front wheel and 4T on the rear.. Did you decide to swap them around?

 

[Doctorbass]

Awesome! now to see how it goes on 400A phase current

For some reason I thought you were putting the faster 3T mxus on the front wheel and 4T on the rear.. Did you decide to swap them around?

Not decided yet... my actual 4T is laced on a 19" rim... if i would replace it without unlacing/swaping the rim i could just swap the rotor... but i have some test to do.

dual 3T will improove torque sustained over all the 1/8 mile but will have lower torque from a start

4T rear and 3T front would give me a bit higher torque but at higher speed like the 3T can do it would become useless and i would loose the torque required to go higher speed than what a 4T can do...

Doc

 

[cycborg]

Oh btw, That is great to pedal relatively LOW rpm at 50km/h !!.. The 60 T and the rear 12T make a huge improovement! I can now contribute to pedal some power at a slow cadance even at speed up to 60km/h

OK, I’m a low-power guy, and this is something I don’t understand about these high-power builds. Why even pretend you’re contributing significant power at 50-60 km/h? Why not just let the motor(s) do 100% of the work at those speeds, instead of 90-95%, and gear it so that you actually can contribute power in the 25-35 km/h range? Is the pedal power just about getting a workout, rather than propelling the bike?

Not asking this to give anyone a hard time - on the contrary, since this is often a feature of builds by experienced builders, it would be a good thing for me to understand.

 

[wojtek]

Is the pedal power just about getting a workout, rather than propelling the bike?

For me it is purely about workout (and police). Obviously human contribution to the overall power is not so material. Still I can get sweaty when pedalling high powered bikes. Great workout indeed!

 

[grindz145]

Wow doc, that front axle setup is insane! Next-level shit. 8)

 

[Doctorbass]

Wow doc, that front axle setup is insane! Next-level shit. 8)

Yeah thanks!.. That was hard time getting every machining done like i need but finally it fit like a glove on the 20mm DH 1200$ White Brother fork!

 

[Doctorbass]

Oh btw, That is great to pedal relatively LOW rpm at 50km/h !!.. The 60 T and the rear 12T make a huge improovement! I can now contribute to pedal some power at a slow cadance even at speed up to 60km/h

OK, I’m a low-power guy, and this is something I don’t understand about these high-power builds. Why even pretend you’re contributing significant power at 50-60 km/h? Why not just let the motor(s) do 100% of the work at those speeds, instead of 90-95%, and gear it so that you actually can contribute power in the 25-35 km/h range? Is the pedal power just about getting a workout, rather than propelling the bike?

Not asking this to give anyone a hard time - on the contrary, since this is often a feature of builds by experienced builders, it would be a good thing for me to understand.

In Drag Racing, every addition of power you get make you better E.T. even small it can be it contribute. i saw a little diff on aceleration at the 1/8 drag strip with the previous 5403 when i pedaled. it improoved my 0-60 time.

AT LOW SPEED WHERE THE POWER FROM THE MOTOR IS WAY LOWER DUE TO LOW RPM BUT THAT YOU ONLY HAVE THE SAME TORQUE, THE HUMAN TORQUE CONTRIBUTION BECOME IMPORTANT. never forget that POWER is TORQUE x RPM. in relative comparaison to the motor, Human can bring great torque to the crank but not power.

In fact at low speed human contribution is more important due to the power ration between human and motor vs torque ratio between human and motor.

In non drag racing situation, even if i contribute for 10% of power average by pedaling, that,s as significant as regen do usually so it Worth i think.

I dont like keeping legs not moving on bike, plus it help for the equilibrium and controling the bike, you feel more the bike handling by pedaling.


Doc

 

[cycborg]

In Drag Racing, every addition of power you get make you better E.T. even small it can be it contribute. i saw a little diff on aceleration at the 1/8 drag strip with the previous 5403 when i pedaled. it improoved my 0-60 time.

AT LOW SPEED WHERE THE POWER FROM THE MOTOR IS WAY LOWER DUE TO LOW RPM BUT THAT YOU ONLY HAVE THE SAME TORQUE, THE HUMAN TORQUE CONTRIBUTION BECOME IMPORTANT. never forget that POWER is TORQUE x RPM. in relative comparaison to the motor, Human can bring great torque to the crank but not power.

In fact at low speed human contribution is more important due to the power ration between human and motor vs torque ratio between human and motor.

I completely understand and agree with all this, but if it’s low-speed torque you’re after, then isn’t lower gearing what you want? Or maybe in the drag-racing context, 50-60 km/h is low speed, since it’s about half your terminal speed and you might hit these speeds 1/4 - 1/3 of the way down the track.

I guess the tradeoff would be that at lower gearing, you’d have a larger torque contribution at low speed, so you could accelerate faster, but with higher gearing, you’d spend more time in your optimal cadence band so your total contribution would be greater.

In non drag racing situation, even if i contribute for 10% of power average by pedaling, that,s as significant as regen do usually so it Worth i think.

I dont like keeping legs not moving on bike, plus it help for the equilibrium and controling the bike, you feel more the bike handling by pedaling

If you in fact do most of your riding at 50-60 km/h, then, yeah, put the power where you’re going to use it. On the other hand, if someone's speeds are more or less evenly distributed in the 25-60 km/h range due to traffic, energy conservation, or whatever, it might make more sense for them to optimize for the lower end of the range.

 

[Doctorbass]

IN the drag racing conditions i will install the 16T rear gear witch helped alot during the first 1/8 mile drag racing i did a month ago. For the interbike and Las Vegas Ride i have installed the 12T but as well i will also bring with me the 16T just in case.

Doc

 

[madin88]

i believe for drag racing the optimal gearing would be 0-20 or 30kmh. than move into a position as aerodynamically as possible of course it should't feel uncomfortable.
or mabye its even better to lower the seat as much as possible for better COG, and lean over the steerer to prevent the bike from a wheelie

my bikes all are geared for 20kmh at about 70crank rpms. i must say that wasn't really planned it just so happenend, but i like it because it makes it possible to pedal up slight grades wihtout motor - otherwise i would have to wheel it home.. with a 2,6:1 schlumpf gear i could pedal up to 50-60kmh but these gears are very expensive so i do joke pedalling at those speeds. i also do not like keeping the legs not moving.

btw. nice to hear you noticed much better acceleration with the MXUS.

 

[Doctorbass]

Yeah For drag racing, 20-30kmh max pedaling is probably the best for the 0-60ft

If you take a look to my video you can see i was pedaling alot with the 60T 16T!


Tis video was a month ago with a single motor (5403)
jump at 20s:

[youtube]LYniYz8OQmc[/youtube]

 

[Baron]

How does 2wd effect top speed? How would the top speed differ on a bike with one motor vs a bike with two identical motors? Also, how does a 1wd bike compare to a 2wd in terms of overall efficiency?

 

[macribs]

How does 2wd effect top speed? How would the top speed differ on a bike with one motor vs a bike with two identical motors? Also, how does a 1wd bike compare to a 2wd in terms of overall efficiency?

My guess is that 2 wd will have better efficiency because both motors will have easier task of pushing the bike to normal speed vs single motor, as single motor will draw more current to reach the same speed. Top speed should increase because total power is double so more power to punch "hole in the air".

 

[wojtek]

2WD will reach top speed faster.

 

[Baron]

How does 2wd effect top speed? How would the top speed differ on a bike with one motor vs a bike with two identical motors? Also, how does a 1wd bike compare to a 2wd in terms of overall efficiency?

My guess is that 2 wd will have better efficiency because both motors will have easier task of pushing the bike to normal speed vs single motor, as single motor will draw more current to reach the same speed. Top speed should increase because total power is double so more power to punch "hole in the air".

2WD will reach top speed faster.

The 2wd will surely accelerate faster, but does it use more total power compared to a 1wd during acceleration?

So is the 2wd more efficient at "cruising" speed since it can get closer to it's no-load speed and use less watts maintaining that speed?

You also have to factor in the added weight of the 2nd motor + batteries in the efficiency of the 2wd bike.

 

[Doctorbass]

Each motor/controler set have a torquer curve. as the motor reach the max no load speed that torque decrease.

It's a lb/ft number for every speed the motor.

It is the same for friction and the wind you have to fight aginst. It require a torque for every speed.

Your bike will be able to continu accelerating if and only if the motor torque is higher than the required torque at the speed you run at.

The no load speed where torque availlable is near zero, is the absolute factor of max possible speed your motor can do in the given voltage condition can go if there would be no air and mechanical friction your bike could go to that max no load speed.


If you double the motor and controller you also double the torque you have at every speed ! .
BUT the REQUIRED torque for every speed remain the same!
so.. if with one motor-controller set, you was capable of max speed of 100km/h and that it required 80 lb-ft this mean your motor was capable of reaching max of 80 lb-ft at that speed and not capable of higher torque for continuing accelerating for the higher speed.
But now if you double the motor/controller set, you now have 160lb/ft availlable at 100kmh witch is higher than what is required for 100kmh so your bike will continu accelerating until it reach the speed where the torque your motor can produce is equal to the torque of the speed you go at.

As well POwer is Torque X Speed so we cold also talk in term of POwer like on the ebike simulator.

btw on that simulator, the bblack curve is the required power at every speed. so you can guess what is your max possible speed by looking the point where the red curve cross the black curve. The speed on the X axis that is in line with that point IS the max speed you can get.

DOc

 

[Doctorbass]

How does 2wd effect top speed? How would the top speed differ on a bike with one motor vs a bike with two identical motors? Also, how does a 1wd bike compare to a 2wd in terms of overall efficiency?

My guess is that 2 wd will have better efficiency because both motors will have easier task of pushing the bike to normal speed vs single motor, as single motor will draw more current to reach the same speed. Top speed should increase because total power is double so more power to punch "hole in the air".

2WD will reach top speed faster.

The 2wd will surely accelerate faster, but does it use more total power compared to a 1wd during acceleration?

So is the 2wd more efficient at "cruising" speed since it can get closer to it's no-load speed and use less watts maintaining that speed?

You also have to factor in the added weight of the 2nd motor + batteries in the efficiency of the 2wd bike.

As i said the new 2WD bike configured for drag racing will have less weight than the 1WD. ( less battery energy, diff battery chemistry and C rate, lower weight motor.)

Doc

 

[Doctorbass]

It's 00:51 here and Only few hours now before the bike will be 99.5% finished! the 0.5% being every little thins we sometime forget...

I finally installed 6 AWG harness to power each controller. Battery is 4 gauge and goes to 4x 125vdc 63A circuit breaker in two group of 2 parallel. This will be able to sustain 126A and about 200A burst per 2p of breaker.

I have to get the bike to NYX office at about 1h30 driving for about 5pm. This will be really short for having one of the most powerfull ebike finished and ready for the show and tested and tuned! lol... I feel like a zombie now.. i realy have to go sleep before i mix red and black wires connection!!!

Doc

 

[Rodney64]

Doc, looking forward to see this bike run and how you programme the 2 controllers to work together using the one throttle.

 

[madin88]

Doc, looking forward to see this bike run and how you programme the 2 controllers to work together using the one throttle.

its not very difficult. you need to program them one by one by swapping the display. one needs to be set as master and the other as slave. than connect them with the Y- cable and connect the display to this adapter. you can set both controllers to do the same or programm them different. at the moment i also build a 2WD system but with two mini-e set both to do exactly the same (they will drive the rear wheels on a 4-wheel rickshaw)

Doc, hopefully you got enough sleep i wish you a great time on the interbike show!

 

[Doctorbass]

OK quick update now:

The bike is in a crate in direction to Interbike 2015 at Las Vegas and should arrive during the weekend.

I had no time to test and tuning before shipping so test will happen at Las Vegas before the show 8)

Yeas.. I know.. I like Adrenaline!

Doc

 

[Jestronix]

I sense massive post incoming !

 

[Doctorbass]

Yes you are right!.. But from now i need the crate to comeback from interbike, rebuild the bike in one piece and finish building the 100kW lipo drag racing pack!

btw this pack will be awsome! 13 miliohms ( abmiant temp of 25C) total resistance!

let's have fun with math!

The optimum voltage to get lowest internal resistance is 3.9V per cell

and 3.9 x 22s = 85.8V witch is exactly what Jeka, the Adaptto engineer recommand as the optimum voltage for max ouput :wink:

Now the peak amp that can be sraw from this pack before reaching the 3.0V is calculated as :
Max allowable voltage drop :85.8V-(22x3.0V) = 19.2V
Max I = (Vdrop / Ir) = 1476A !!!.. That's 97.4kW !!!
These pack are rated 150C.. and these are 9Ah total.. That's pretty close with (9Ah*150C)=1350A

The amp limit will be the controller and the 8 gauge wire!.. But the fusing point of 8 Awg copper wire of these pack is 475A and i have two parallel ... so.... let say the max amp is: 950A.. That's stil alot !!! 950A * 0.013 = 12.35Vdrop = 73.5V pack volt at 950A... That's 69.8kW... right before seeing these silicon wire red hot !!!

That is still more than twice the current that both of my controllel rwill draw ( 375A and 32kW)!

This awsome pack will be 6" x 4" x 6".

I will build a strong aluminum box to keep cells compressed and help keeping low internal resistance.
Both end will be 3/16" T6 allu and sides and bottom will be 3/32".

Doc

 

[izeman]

i thought canada uses metric system?

 

[Doctorbass]

i thought canada uses metric system?

We use Both... as well as we speak French and English! :wink:

Doc