Voltage and current measurement of NISSAN LEAF

Hello everybody!

I am a student performing my thesis on the energy flow in the nissan leaf.
For this I need to measure the voltage and the current from the battery.
A possibility is measuring the CAN data which I will also do, but I'd like to measure it in a physical way as well in order to analyze the accuracy of the CAN data.
So my question is where I can measure the voltage and the current from the battery, what tools I need and what dangers there exist?

Thank you in advance!

CAN message document which has a lot of the data normally communicated on the two main busses. Message 1DB on EV CAN is what you want. I believe you can query the LBC (BMS module) for a more accurate value, since the standard message only has a 0.5 V precision.

Spend $20 downloading the Leaf service manuals from the nissan service site ($20 buys you a 24 hour access to the portal, search elsewhere on this site about it).

You'll have to talk to your professors about how to do a shunt, my guess is the best way would be to go through the service disconnect or fuse (2011-2012 cars) that's accessible from outside the pack. Keep in mind the leaf has a high voltage system running at 395V fully charged and about 250 amps maximum motor draw. I'd do as much as I could with the CAN messages first. The leaf uses a hall-effect current sensor so it's probably not that accurate for low levels of current. Ingineer, the guy who runs EVSE upgrade probed the HV bus to see how accurate the voltage measurement was and as I recall he found it pretty accurate (he posted his results somewhere on this forum).

JeremyW said:

Keep in mind the leaf has a high voltage system running at 395V fully charged and about 250 amps maximum motor draw.

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The leaf service fuse is 450VDC rated at 225Amp, So cant see that the motor could draw 250 amps

They have this service fuse inside them
https://www.pecj.co.jp/en/fuse/ev/evfp_30.html


What sort of AMPS have we actual see from can message relating to current draw and volts from battery and motor ?

TrueSoln,

The documentation you referenced shows that fuse will carry 110% of rated current for 4 hours so it would easily carry 250 amperes for long enough to discharge the traction battery. The 80 kW motor in a 2011 through 2017 LEAF is capable of drawing at least 270 amperes to produce its full rated output if the traction battery is down around 300 volts and a traction battery in reasonable condition is capable of delivering that much current if there are no really weak cells. I know from personal experience that the 2011 and 2015 motors will draw enough current to produce their full 80 kW rated output even when the battery is below the very low battery warning threshold. The 2019 Plus has a motor rating of 160 kW so it is capable of drawing twice as much current.

I know from personal experience that the 2011 and 2015 motors will draw enough current to produce their full 80 kW rated output even when the battery is below the very low battery warning threshold. The 2019 Plus has a motor rating of 160 kW so it is capable of drawing twice as much current.

Click to expand...

Interestingly, these versions - including the ePlus - all use the same motor, which was changed for 2013 to use less expensive magnets. It's the inverter that has been increased in capacity twice, so the little motor that produces 80kw/108HP of power in a 2013 also produces 200+HP (and whatever that is in kw) in a 2020 ePlus.

Interestingly, these versions - including the ePlus - all use the same motor, which was changed for 2013 to use less expensive magnets. It's the inverter that has been increased in capacity twice, so the little motor that produces 80kw/108HP of power in a 2013 also produces 200+HP (and whatever that is in kw) in a 2020 ePlus.

Click to expand...

I would infer from this Leftie that this little motor should probably not be used to capacity except occasionally- hard to imagine it holding up very long under full amperage? OTOH our Plus has so much power that we have never really tapped it.....

dmacarthur said:

Interestingly, these versions - including the ePlus - all use the same motor, which was changed for 2013 to use less expensive magnets. It's the inverter that has been increased in capacity twice, so the little motor that produces 80kw/108HP of power in a 2013 also produces 200+HP (and whatever that is in kw) in a 2020 ePlus.

Click to expand...

I would infer from this Leftie that this little motor should probably not be used to capacity except occasionally- hard to imagine it holding up very long under full amperage? OTOH our Plus has so much power that we have never really tapped it.....

Click to expand...

I'm not certain of this (my memory is bad) but I seem to recall that full power is limited to something like 30 seconds in the 2018+ Leafs. This is more common than you'd think with EVs. It just isn't widely publicized, for some reason.

I know that after 30 seconds I am going 100 MPH, I have tried it, not something I will ever need to do again...... and I do not see a lot of complaits about the Leaf motors, let's hope that they hold up well....

LeftieBiker said:

It's the inverter that has been increased in capacity twice, so the little motor that produces 80kw/108HP of power in a 2013 also produces 200+HP (and whatever that is in kw) in a 2020 ePlus.

Click to expand...

Or the motor controller was initially designed for the latest (ePlus) power output & battery rating, and just the controller input was limited
based on the desired motor output (limited by battery).

So I ran a Matlab simulation to try and get what I believe is the correct amount of motor current that that is used by the Nissan Leaf Gen1+2. The fuse on most EV battery packs have specs that allow for things like current spikes or exceeding maximum ratings for periods of time. They also have thermal fuse links as well (in lots that I've dealt with at least) to prevent things such as stator windings or DC bus bars from affecting the temperature of the battery componentry or vice versa. With all of that out of the way, my program showed that in order to reach 250NM of torque (2013-16 models) the motor needs around 384 amps of stator current (stator current = DC current for WYE configuration motors). The base speed will be around 3050 RPM based on the limited power output. When running a standard MTPA, FW, and MTPV algorithm you'll find that max power with the battery fully charged is around 129 kW and a base speed of 3737 RPM. The motor doesn't even need MTPV until you get past 456.25 amps (based on D-axis inductance values and PM rotor flux). Even then it's not really going to contribute until you pass 571 amps. This power output is what the Nissan leaf ePlus has, albeit with 340Nm of Torque and not 455 like what it is capable of. Nissan clearly overbuilt the rotor and stator but underbuilt it's cooling capability. The EM57 only has a water-jacket around the stator and has no rotor cooling (from what I can tell). Modern high performance motors such as in the Model 3 and Rivian RT1 Dual motor (upper spec) have oil cooled stators and rotors. The stator has oil forced through the electrical steel and the rotor has oil sprayed onto an internal heat spreader.

Ld = 1.6 mH
Lq = 4.3 mH
Lambda_m = 73 mWb
Rs = 23 mOhms

TrueSoln said:

JeremyW said:

Keep in mind the leaf has a high voltage system running at 395V fully charged and about 250 amps maximum motor draw.

Click to expand...

The leaf service fuse is 450VDC rated at 225Amp, So cant see that the motor could draw 250 amps

They have this service fuse inside them
https://www.pecj.co.jp/en/fuse/ev/evfp_30.html bloxd io

What sort of AMPS have we actual see from can message relating to current draw and volts from battery and motor ?

Click to expand...

Can you provide any recommendations for higher-rated fuses that could handle a motor drawing 250 amps?