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Somewhere in the builds forum my Opel GT conversion thread is collecting dust. I've been crawling along at a snail's pace as I usually don't have time and money at the same time. But progress slowly continues. One thing I have settled on is using a Nissan Leaf motor. But I want a lot more power out of it than Nissan pulls. It appears that the Leaf motor is grossly underrated at 85kW and the limit in the Leaf is more a function of their puny battery. Several people have gotten more than 200kW out of it for short periods of time. But how high can it go? My question falls into two categories; Current and Voltage.

Current: Apparently forum member Arlo over on Endless Sphere has cranked up the phase current to 750Arms. This is probably pushing it pretty close to the limit, but the inverter I'm thinking of has a limit of 600Arms which should be comfortably within the limits. Anyone else have experience over-currenting the motor?

Voltage: This is the bigger unknown. Arlo only went up to 470VDC on his bus voltage, but I think this was more a function of his discomfort with higher voltages, rather than the limits of the motor. But I don't know for sure. I'd be surprised if the insulation did not go up to 600V or higher. And in the stock Leaf, the motor appears to go into field weakening far lower (less than 3000 RPM) than the mechanical maximum (over 10,000 RPM). So there does seem to be some potential for a big power boost here. Does anyone have an idea on this? What's the highest anyone has pushed this motor in terms of voltage?
 

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It appears that the Leaf motor is grossly underrated at 85kW and the limit in the Leaf is more a function of their puny battery. Several people have gotten more than 200kW out of it for short periods of time. But how high can it go? My question falls into two categories; Current and Voltage.
It's 80 kW in the first generation (with the 24 kWh and 30 kWh batteries), 110 kW in the base model of the second generation (with 40 kWh battery), and 160 kW in the Plus version for 2019 (with the 62 kWh battery)... but yes, the consensus seems to be that the battery is the limitation. It's also battery cooling (or the lack of it), not just size - the little 16 kWh Volt battery is good for 120 kW briefly, even in the stock Volt. This assumes that there is no significant physical difference between the motors of these Leaf versions.

Aside from the battery, I think there will be another factor in addition to motor current and voltage: cooling. It doesn't matter for an instantaneous burst, but any sustained use will at some point produce heat faster than the cooling system can remove it.

And in the stock Leaf, the motor appears to go into field weakening far lower (less than 3000 RPM) than the mechanical maximum (over 10,000 RPM).
That makes sense, because "field weakening" (which I think is much more understandable as phase shift of the applied power from the rotor position, just like advancing DC motor brushes) is unrelated to the mechanical limits on speed; it's an electromagnetic issue, not a mechanical issue. Presumably if you use higher voltage to run the motor faster, more shift may be necessary to run properly at the higher speed.
 
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