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[Lecram]

When my bike is in sports mode and I want to accelerate, the bike starts slowly and acceleration increases at higher speeds. Especially with a passenger on the bike, I am barely faster away from the traffic lights than the cars. My KTM is much faster at low speeds. It seems that the Zero has reduced torque at low speeds.
is that normal? And is that adjustable?

[firepower]

Think it may be a limit of the motor controller

S & DS Gen 4 size 4 420A max current to motor.
DS Acceleration, 0-60 mph (0-100 km/h)   9.4=5.2 seconds    12.5=5.7 seconds   12.5+PT=6.4 seconds
S   Acceleration, 0-60 mph (0-100 km/h)   9.4=4.8 seconds    12.5=5.2 seconds   12.5+PT=5.8 seconds

SR Gen 4 size 6 660A max current to motor.
Acceleration, 0-60 mph (0-100 km/h)   12.5=3.3 seconds   12.5+PT=3.9 seconds

Zero may also be limiting max torque at take off for safety and liability reasons, wish they would allow an insane mode unlock like Tesla has

[CScalpeL]

I would suggest you quantify your acceleration to see how far off spec the bike is. You can use your cell phone to capture the speedometer while doing accelerations and then analyze the frames after to determine your times.

Remember to take into account your weight and the PT (if you have one) when comparing to the spec.

[RNM]

Lecram, 0-100 km/h in 6,4 is not exactly slow.
If in doubt, time your bike.

[M@2015DS]

I can sense a very slight delay on my DS from a stop (0-10MPH?) but after that it ratchets up quickly. I knew that I was obviously not going to get the fastest bike in the Zero lineup so I did not expect that much. In sport mode I am getting zero to sixty in around 5 seconds no problem. That is faster than a Mustang GT so I don't think it is particularly slow.

[teddillard]

... That is faster than a Mustang GT so I don't think it is particularly slow.

um, no.  http://www.0-60specs.com/ford-mustang-0-60-times/

[Biff]

When my bike is in sports mode and I want to accelerate, the bike starts slowly and acceleration increases at higher speeds. Especially with a passenger on the bike, I am barely faster away from the traffic lights than the cars. My KTM is much faster at low speeds. It seems that the Zero has reduced torque at low speeds.
is that normal? And is that adjustable?

See the article that Ted wrote up here, and pay close attention to the comments.

https://evmc2.wordpress.com/2014/07/07/motor-starting-torque-stall-torque-and-motor-types/

The Dyno chart from motorcycle consumer news shows that the motorcycle has relatively constant torque from 1000 RPM (their dyno lower limit) up to 3200 RPM (that is from 17mph up to 55mph) .. the  flatness of the torque curve remains even at lower RPM.

http://www.motorcycleconsumernews-digitalmagazine.com/mcnews/september_2014d?pg=20#pg22

The "slow" acceleration at lower speeds is purely a human perception, not an imposed limitation on the vehicle.

Cars typically have a first gear that will shift at around 20mph when casually accelerating from a stop, when they shift, the wheel torque drops and thus acceleration also decreases for the same throttle position .. in the electric you don't shift, you just keep accelerating.  I believe humans perceive the acceleration of the bike becoming faster, but really it is just faster in comparison to your point of reference, vehicles that have to shift.

-ryan

[Lecram]

Thanks Ryan, but it's for sure not a perception. I own a KTM 990, too, and this bike will lift it's frontwheel, even at 3rd gear. It's way faster from standstill than the Zero. A VW T4 was almost as fast as my DS.

[RNM]

Lecram,

See this topic
http://electricmotorcycleforum.com/boards/index.php?topic=4635.0

[steven_first]

I just learned a bit ago we have been all wrong about the amperage rating of the gen4 systems.  Look at this PDF on page 2. 96V to 120V size 4 is only 300A that is unless we are using the 72v to 80v controller whereas the current is still 350A (not counting burst). http://www.sevcon.com/media/2461/Gen4%20Aug%202013%20web.pdf

[Lecram]

I just learned a bit ago we have been all wrong about the amperage rating of the gen4 systems.  Look at this PDF on page 2. 96V to 120V size 4 is only 300A that is unless we are using the 72v to 80v controller whereas the current is still 350A (not counting burst). http://www.sevcon.com/media/2461/Gen4%20Aug%202013%20web.pdf

The peak current is 360A for 10 secs. That's what it should deliver when accelerating from standstill

[protomech]

I just learned a bit ago we have been all wrong about the amperage rating of the gen4 systems.  Look at this PDF on page 2. 96V to 120V size 4 is only 300A that is unless we are using the 72v to 80v controller whereas the current is still 350A (not counting burst). http://www.sevcon.com/media/2461/Gen4%20Aug%202013%20web.pdf

The S / DS use the G8035 Size 4, the SR uses the G8055 Size 6. These controllers top at 116VDC, despite the nominal 80V rating.

[Biff]

I just learned a bit ago we have been all wrong about the amperage rating of the gen4 systems.  Look at this PDF on page 2. 96V to 120V size 4 is only 300A that is unless we are using the 72v to 80v controller whereas the current is still 350A (not counting burst). http://www.sevcon.com/media/2461/Gen4%20Aug%202013%20web.pdf

The peak current is 360A for 10 secs. That's what it should deliver when accelerating from standstill

The peak current for the 80V Gen4 is
Size2: 180A (2013 XU)
Size4: 350A (FX, S, DS)
Size6: 550A (SR)

From page 3-9 of the user manual:
http://www.thunderstruck-ev.com/Manuals/Gen4_Product_Manual_V3.0.pdf

However on page 4-3 It goes into more detail with a graph that shows that "boost" region allows for 120% of the short term current for up to around 30seconds, which ends up providing the following current limits
Size2: 216A (they actually boosted that boost on the size2 up to 250A)
Size4: 420A
Size6: 660A


-ryan

[RNM]

The peak current is 360A for 10 secs. That's what it should deliver when accelerating from standstill

Lecram, it's a limitation of the ESC. Full current (full torque) at 0 rpm would induce great current ripple because the BEMF is very low. To have full current, you would have to increase ESC switching freq a LOT, but that means a lot of additional heat (=burned MOSFETs)

[Biff]

The peak current is 360A for 10 secs. That's what it should deliver when accelerating from standstill

Lecram, it's a limitation of the ESC. Full current (full torque) at 0 rpm would induce great current ripple because the BEMF is very low. To have full current, you would have to increase ESC switching freq a LOT, but that means a lot of additional heat (=burned MOSFETs)

in fact the Sevcon Gen4 does provide full current at 0RPM, until temperatures get up and the controller starts reducing current to maintain operating temperatures.

-ryan