Just a point of clarification about balance charging. Balance charging only occurs when the normal AC charge (ie on Granny Charger or Type 2 charging from either a home wall charger or public charging post) and cannot be done after reaching 100% on a public DC Rapid Charger. The reason is that a balance charge is a slow low power charge and is delivered over a completely different set of wiring connecting each cell in the battery pack to the Battery Management System (otherwise known as the BMS). One of the functions of the BMS is to look at the charge of each Cell in the Battery Pack and finetune the charge on each cell so that the pack as a whole performs optimally. This fine-tuning may take as little as 20 minutes but if there have been a lot of charge/discharge cycles whether as overnight AC charges or Rapid DC chargers since the last Balance charge, then the individual cell voltages will be more varied from one to another. This is because when normally charged or driven the batteries are connected in series that is one after the other with the positive of one to the negative of its neighbour, like batteries in a flashlight. This way the individual 4 or so volts get added together to form the EV's 400-450 volt High Voltage Traction Battery. In an ideal world, every battery cell would be identical and when charged with a High Voltage they would all charge up equally. In the real world every cell is unique and when charged some will charge a little better and others a little less well but by only tiny fractions of a volt. But as the EV is driven and is discharged and then charged these minute differences accumulate. So next time the battery is fully charged to the set 100% the BMS stops the high voltage charging of the pack end to end and using the thin wires connected between each cell the BMS first senses the voltages of each cell and then using the preprogrammed algorithm delivers small adjustments of charge at low voltage. This is why after a 7 kW AC charge over several hours the charge will drop from 7,000 watts to only 200-300 watts during the balance charge. This Balance or Equalisation Charge will trickle charge normally for 20 to 30 minutes if done once every week or so but if the cells are way out of balance it will go on either until all the cells are within limits or 3 to 6 hours before time out (depending on the BMS and pack size).
One final point on charging. There are broadly two main types of Lithium Ion battery cells being used in EVs today and MG is using both types namely the Lithium Nickle Manganese Cobolt known as "Li-Ion" or "Li-NMC" and the "Lithium-Iron-Phosphate" cell chemistry also called "Li-FePO4" or "LFP" for short. There are many reasons why one battery chemistry should be chosen over another but suffice to say that in a given volume you get a greater Electrical Energy Capacity ie kWH with Li-Ion but LFP is less expensive, more stable (doesn't catch fire) and doesn't use controversial Cobolt.
51 kWh MG4 Standard Range and MG ZS Facelift Standard for example have LFP and their Long Range brothers and sisters have Li-Ion. You'd notice the practical difference on the CHarging Screen of the Infotainment system. The Li-Ion cars have the ability to set an 80% charge limit for daily use and a 100% charge limit for the full range if you have a longer trip or you want to do a balance charge. This is because Li-Ion degrades more quickly if charged to 100% and kept at a high state of charge. With LFP EVs, you cannot set 80% limit because LFP chemistry is stable at 100% state of charge (SOC), and doing so is beneficial to the long-term cell health.
