ZS EV LR Will suddenly not fast charge

[Chris Law]

My ZS is almost 2 years old. During a 2000 km trip from France to Portugal, over 4 days, the car initially performed normally at CCS chargers, charging at up to 62kW. After a charge on day 3 at a BP Pulse Iberdrola charger, the Bluetooth stopped working (Wired and dongle). At the next charge and all subsequent charges, the rate did not go above 25kW. I used various providers (Tesla, BP Iberdrola, Ionity, Endesa). I considered disconnecting the 12V battery but decided against it until we reached home. After reaching home I did this and the BT problem was solved. However, charging has stayed in the 20skW. Has anyone experience with this or tips? I have contacted the dealer but will not get a response today.

 

[hmadsen]

2 things i can think of.

1. 2000 km in 4 days, all on CCS, could make the car derate the charging due to repeated CCS charges, which can be harder on the battery, the car will derate the charge speed to protect the batteries (Well to make sure they dont go below the warranty limit, to prevent them from having to give you a new battery)

2. Loads of CCS charges = Loads of "to 80%" charges = Batteries have not been balanced. If the battery balance between cells gets to high, it might limit the current to protect the batteries.

First thing to do is....Try sticking it on a wall/home/destination AC "Charger" and set the limit to 100% and leave the car to charge until it stops and says it has finished. Then drive it and when it needs a charge, try to stick it on a CCS, if it was cell imbalance, the balance charge you did, should fix it.

Could also be a bad battery module, which again would mean an imbalance and lower charge amps to protect the batteries.


Remember, when doing DC charging, the charger is not onboard, but the onboard charger is still responsible for regulating the wattage to the battery.

So it is the OBC that limits the current, it tells the CCS charger how much current to feed the batteries, so it is almost surely because the OBC is "mad" about something.

If the balance charge does not solve it, an MG service workshop should be able to get the car to tell, where it hurts

 

[Chris Law]

2 things i can think of.

1. 2000 km in 4 days, all on CCS, could make the car derate the charging due to repeated CCS charges, which can be harder on the battery, the car will derate the charge speed to protect the batteries (Well to make sure they dont go below the warranty limit, to prevent them from having to give you a new battery)

2. Loads of CCS charges = Loads of "to 80%" charges = Batteries have not been balanced. If the battery balance between cells gets to high, it might limit the current to protect the batteries.

First thing to do is....Try sticking it on a wall/home/destination AC "Charger" and set the limit to 100% and leave the car to charge until it stops and says it has finished. Then drive it and when it needs a charge, try to stick it on a CCS, if it was cell imbalance, the balance charge you did, should fix it.

Could also be a bad battery module, which again would mean an imbalance and lower charge amps to protect the batteries.


Remember, when doing DC charging, the charger is not onboard, but the onboard charger is still responsible for regulating the wattage to the battery.

So it is the OBC that limits the current, it tells the CCS charger how much current to feed the batteries, so it is almost surely because the OBC is "mad" about something.

If the balance charge does not solve it, an MG service workshop should be able to get the car to tell, where it hurts

Thanks for your thoughts. I did balance charge before the journey and at the first 2 of 3 overnight hotel stops. I'm booked into my dealer on 21/1 (they offered earlier but I am out of the country).

 

[Chris Law]

Update: At the dealer yesterday. They spent a day with the car, speaking to MG along the way. They do not have a CCS charger on site and did not use one during the day. They did observe some problems with the HV battery and asked me to balance charge it multiple times, including leaving it on charge for up to 48 hours. I only use a granny charger at home. This was better for me than leaving the car there for several days and I agreed. As a precaution and with their agreement, I also made another appointment for 16 Feb (the earliest mutually available date), on the assumption the problem would not be solved (if it is, I will cancel). The car works fine, except for not charging above 25 kW, so not (yet) an issue as I don't plan on any long journeys until March. They did advise me to make contact with MG myself to put a marker down for any possible guarantee claim later. To be continued....

 

[Nej]

Chris,

Do you have an update on this situation please? I have just purchased a 2022 ZS (literally 6 days ago), only to discover this issue when we decided to take a little jaunt to the seaside. I just swapped up from a 1st gen Leaf because of better range/charging, so this was especially exhausting.

I'm about to go and hook up the car at a local Park and Ride to let it charge for 24 hours to see if it resets (we don't yet have long enough cables at home to charge there). The dealer insists that this is not a problem as it "still charges rapidly", but it's a deal breaker for me as the charging time would be doubled on a rapid!

 

[Chris Law]

Chris,

Do you have an update on this situation please? I have just purchased a 2022 ZS (literally 6 days ago), only to discover this issue when we decided to take a little jaunt to the seaside. I just swapped up from a 1st gen Leaf because of better range/charging, so this was especially exhausting.

I'm about to go and hook up the car at a local Park and Ride to let it charge for 24 hours to see if it resets (we don't yet have long enough cables at home to charge there). The dealer insists that this is not a problem as it "still charges rapidly", but it's a deal breaker for me as the charging time would be doubled on a rapid!

Hallo Nej,

Yes, I do have a progress report. The situation is not fully resolved but is improving. I have now balance charged with my granny charger about 20 times, leaving the car connected for up to 48 hours (remembering to cancel scheduled charging).

Initially the car fast-charged at a maximum rate of 25kW. On 31 January I got a max of 32kW. After repeated balance charging, on 8 Feb I got a max of 38.5kW. Some more balance charging gave me 48kW on 11 Feb.

I was then absent for 10 days and am since yesterday continuing the same actions. I had an appointment at the dealer yesterday but changed that to an annual service and R25-R27 update as I want to reach a stable charging maximum before returning to the dealer with a complete story.

Good luck with your problem.