Nissan Ariya achieves 5 Star Rating by Green NCAP

[Rob]

Nissan Ariya has achieved the maximum 5-star rating and confidently reaches a Weighted Overall Index of 9.6 in at Green NCAP – an independent initiative aiming to highlight the work of specific carmakers and models that go above and beyond minimum sustainability requirements, causing minimal harm to the environment.

Green NCAP’s rigorous testing process analyses in detail all aspects of a car’s sustainability credentials. The test contains 3 separate sections: Clean Air Tests, Energy Efficiency Tests and Greenhouse Gases Tests. These tests are then used to calculate a model’s overall score.

Having no tailpipe, Nissan Ariya naturally achieved a perfect 10/10 in the Clean Air Index test. This included top scores in the Laboratory Test and the Road Test; the two constituent sections of the Clean Air Index. Furthermore, high scores of 9.3/10 and 9.5/10 were recorded in the Energy Efficiency Index and Greenhouse Gas Index sections of the rating respectively.

The standard On-Road Drive was performed in cold weather at -1°C and Ariya’s consumption was about 24 kWh/62 miles. The usable battery capacity measured by Green NCAP is 89.6 kWh, which is more than the officially declared value. When charging with 11 kW, the overall efficiency is 91.6% of energy drawn from the electricity grid. This represents “the highest value measured by Green NCAP so far” per a quote in Green NCAP’s report.

“At Nissan, we are deeply committed to our sustainability and electrification goals as outlined in Ambition 2030. It is wonderful that Green NCAP has recognised the Ariya as being at the forefront of this eco-revolution. We are so proud of everyone across the team who has worked tirelessly to accomplish this achievement” said Arnaud Charpentier, Region Vice President, Product Strategy and Pricing, Nissan AMIEO.

With a maximum range of 329 miles along with rapid charging capabilities, the all-electric Nissan Ariya embodies Nissan’s commitment to a cleaner future. There has never been a better time to go electric, and thanks to the Green NCAP’s 5 star rating, the Ariya represents the best possible option for consumers across the region seeking greater sustainability in their everyday lives.

[Milkfloat]

I would love to see the data that concludes 91.6% overall efficiency. My data shows losses at over twice that.

[Cosmyc]

Delta Electronics, which is the manufacturer of the 7.2kW and 22kW on board chargers for the Ariya, claims "better than 93% efficiency", and indeed at least in my case with the 7.2kW charger the efficiency is very high, lower than 10% losses for sure as I measured.

[Milkfloat]

The claim is that those very small losses, 8.4%, are applicable to energy drawn from the electricity grid. There are many losses in the total EV system including wall charge unit/cables/plugs, on board charge converter, battery charging losses, battery discharging losses and inverter/motor losses. Try comparing the kWhrs invoiced to what the Ariya App claims is the energy usage. Typically, it is the latter value that we are using as our guide to efficiency of the car but you will find that the invoiced units are at least 20% higher. Just the motor and Delta converter together lose well over 10% of invoiced power! We don't have a radiator/fan assembly that would manage a 1.0 litre engine for nothing.

[Cosmyc]

The claim is that those very small losses, 8.4%, are applicable to energy drawn from the electricity grid. There are many losses in the total EV system including wall charge unit/cables/plugs, on board charge converter, battery charging losses, battery discharging losses and inverter/motor losses. Try comparing the kWhrs invoiced to what the Ariya App claims is the energy usage. Typically, it is the latter value that we are using as our guide to efficiency of the car but you will find that the invoiced units are at least 20% higher. Just the motor and Delta converter together lose well over 10% of invoiced power! We don't have a radiator/fan assembly that would manage a 1.0 litre engine for nothing.

I disagree.

I'm accounting for everything except discharging, inverter and motor losses. I'm also contabilizing them with the measurement indicator of various power walls and street chargers that I've used.

If I charge my Ariya from 10% to 100% and the street charger says I've consumed ~83kWh, and then we assume 90% of the 105% usable range (I'm also taking hidden usable buffer below 0% into account of 5kWh aprox) is 74,6kWh of 87kWh that results in 8,4kWh losses, which is exactly 10% of what the charger says it has delivered, that seems to be very reasonable.

Even after that we can underestimate the efficiency of the motor to have like 90% efficiency, and that 10% turns into 11,1%, it would only remain the discharging battery losses (which are usually 1kWh aprox in a full discharge) and the inverter ones which are unknown, even after all that I doubt that the losses goes to higher than 15% or even just 15% alone.

But the article point and my initial point in my previous post was that charging losses are about right around that 8,4%.

[Milkfloat]

OK Cosmyc. I was confused into thinking that overall means overall rather than solely charging efficiency. So, getting it from AC and into the battery lost 8.4%. It is not irrational to consider that the losses would be much the same to get the power back out of the battery and converted to AC. Then another 8% loss across the motor. (which will run most of the time between about 88 and 94% efficiency dependent upon speed). Finally, another 3% loss for ancillaries, that few seem to ever consider, and the total loss is over 20%. I have done the % SOC calculation many times and made the same assumptions as you. Now I just look at the kW consumed shown in the App but I use the invoiced power if I want to understand the real cost per mile which includes the 20+% total losses in the system.

[Cosmyc]

Fair enough