As I understand it the lithium Iron EV batteries degrade because of five main reasons:
1) High temperature (leaving car in sunlight or charging when the battery has been used heavily, prior to charging)
2) Charging the battery above 90% regularly - which I think MG are advocating even with the new BMS (takes it to 95% I understand?)
3) Allowing the battery charge to drop below 20% charge regularly.
4) High charge or discharge - again the forum seem to suggest that rapid charging will not adversely affect the battery as long as it is rebalanced?
5) the number of charging cycles.
So given the freedom to choose how we drive and charge our MG ZS EVs do we have views on what is the best driving and charging plan that will make sure whole life battery performance is optimised? And Why?
Also if 1) is a real problem then why don't the public EV charging points come with a solar cell canopy to park under?
As well as my MG, I've had a 2014 nissan leaf for about 3 years. We have always trickle charged it on a granny charger and don't often charge it to 100%. When we've had it checked over by Nissan, the mechanic said the battery was in the best state they had ever seen at that age. It's on 85% SoC at 7 years old and that's with older Li-Ion tech and no liquid cooling.
In response to your list of reasons for battery degredation, I thought ~I'd just add some details around why they cause degredation.
1) Lithium batteries operate best between +5C and +45C so summer weather in the UK isn't likely to be a problem and when you are using the battery it can be heated or cooled by the batteries coolant loop.
2) The majority of the degradation in charging does come from charging from 80% to 100% of the total battery (not the usable) and the higher you go the more impact it has. It causes more degradation than the whole of the 0% to 80% charge. So if you can charge to only 80% or 90% you will get better life out of you battery. Having said that the hidden buffer that is built into the BMS will protect the car from most of the damage.
3) The lower end of the SoC runs the risk of over discharge, if this happens to a cell it may die completely and become unusable. Not really an issue as the BMS prevents it, as long as you don't leave the car for an extended time at a low charge level, it isn't a problem
4) High drain or high charge rates do impact on the batteries life. At higher current levels small lithium deposits form inside the cells, this reduces their effectiveness and overtime can lead to an internal short circuit and a dead cell.
5) Charging cycles cause degradation but the amount of degradation is related to how quickly the car is charged. I'm sure I heard somewhere that slow charging actually keeps the battery healthy more than having it sat doing nothing for extended periods. On the 2kW granny charger you'll be having minimal impact, even on a 7kW charger your not really putting the battery under strain (10% of it's max continous load). If you rapid charge on a regular basis there will be greater degredation over time but this would build up over years.
So all this into account my suggestions for maximising battery life would be,
1) If you can, only charge to 100% when needed, otherwise charge to 80%. Although an occasional charge to 100% has benefits in terms of rebalancing the cells
2) Only use rapid chargers when necessary, this is by far going to have the biggest impact. And when you do use them only charge to the level needed for the next leg of your journey (with some leeway)
A lot of the concerns around battery life are not there with the MG compared to our Leaf. Temperature isn't an issue with the liquid cooled battery. The Li-Ion tech is newer and the load to size of the battery is more conservative. The cars software will tell me if I need to balance the cells, with the Leaf I periodically have to check using leaf spy. So I really think you could quite happily rapid charge to 100% as your only method of charging and the battery would still hold out quite well.