True. But calendar life, and especially temperature history, seem to be much larger factors.
The MG ZS EV SR seems to be LFP chemistry. Ideal for the subtropical climate where I live (Brisbane, Australia). It rarely (one or two nights a year) gets below freezing here.
Agree, but charge cycles are as important. A longer range results in fewer charge cycles, giving less degradation than a smaller battery. The LFP batteries don’t suffer as much from 100% SOC charging than the NMC batteries. In the LR ZS the user is able to set a limit on the charge level, only going to 100% when needed for a long journey. I believe the SR version always charges to 100% SOC ?
It is generally accepted that Li Ion batteries lose between 15 to 20% of capacity over 500 charge cycles. I know the warranty on the batteries in the MGs is 80,000 while maintaining up to 70% of the original capacity (effectively range).
The SR has a range of around 200 miles.
80,000 / 200 = 400 cycles. Clearly they are expecting the worse and taking into account other issues that can cause degradation as the number of charge cycles is not a limiting factor for the warranty.
The LR has a range of 270 miles. This gives about 300 charge cycles.
Based upon 500 charge cycles:
SR is good for 100,000 miles before it loses 15% to 20% of its range due to charge cycling.
LR is good for 135,000 miles before it loses 15% to 20% of its range due to charge cycling.
The excellent BMS systems provided in BEVs limits other effects such as temperature. The new ZS EV allows the user to warm up the battery before charging as well. Unfortunately, it doesn’t show battery temperature anywhere :-(
Oh, and the Nissan Leaf has no thermal control of the battery other than limiting charge rates if it’s too hot or too cold. It also limits output power if too hot. RapidGate is a good thing to search on.
Here is some interesting reading..
Here is an interesting battery degradation test of two years old 2019 Tesla Model 3 Long Range, conducted by Bjørn Nyland.
insideevs.com