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That doesn’t seem to explain why other cars are getting less range from batteries with similar capacity.
by mikeash 7y ago
That doesn’t seem to explain why other cars are getting less range from batteries with similar capacity.
- baybal2 7y agoRegen, BMS, mass and aerodynamics
- kenhwang 7y agoNMC batteries needs to be much bigger/heavier to match the capacity of NCA due to NCA's better energy density. Then you have both the increased weight and increased cooling burden associated with the larger NMC battery that negatively impact range.
- mikeash 7y agoThat doesn’t add up. The I-PACE and Taycan both have similar weight to the Model X, yet are substantially less efficient. The e-tron is lighter than a Model S and has absolutely horrible efficiency.
- kenhwang 7y agoThe e-tron is similar in weight, size, and power to the Model X and pretty much gets within 10% of its efficiency comparing WLTP ratings. I think the efficiency loss can be explained by cooling (if this article is to be believed that Audi has more complicated/expensive cooling) and aerodynamics (it has a normal SUV profile vs the coupe of the Model X).
- mikeash 7y agoI found about 250 miles for the e-Tron and 315 miles for the Model X competing WLTP ratings. I imagine aerodynamics are a huge factor in this difference.
- kenhwang 7y agoFor 83.6kWh usable battery on the e-tron vs 95kWh on the Model X.
- mikeash 7y agoAh, I just saw 95kWh and figured it was close. I didn't realize the usable was so different. I'm a bit suspicious of the WLTP ratings for these cars. The EPA rating for the Model X Long Range is 325 miles, while the e-tron's EPA rating is only 204 miles. Any idea why the Model X would score lower on WLTP while the e-tron would score so much higher?
- kenhwang 7y agoThey probably just have different blends of city/highway/speeds. Just like how gasoline cars have different estimates from different testing agencies, electric cars do too because they all have different efficiency curves. The ratings generally try to mimic the driving conditions of the region and automakers tend to optimize for their home turf. So it's not too surprising the American automaker does better on the American test and the Europeans do better on the European test.