Range declining?

[sbwithers]

I'm in New Zealand. I've had my eZS since November 14th. At first, the range was just as I would have expected. I went for a long drive the day after getting the car It easily did 193km before the battery low light appeared. Awesome.

But the range has gradually been declining. Day to day, I don't really notice as I live in a small town and might only drive 10km.

But when I attempt longer trips I find my range to flat is now, effectively, about 150km. Last week, I drove 670km to Wellington and returned the next day. I wasnt able to drive more than 100km without getting the low battery warning. Sometimes even less. When I charged, from 6% to 96% (in one example) the car only gained 23kWh. That means my max charge seems to now be 26-27kWh..... The same as my 2016 30kWh LEAF.

I seem to have lost access to about 15kWh......

I have the warranty process underway - awkward at Xmas / NY - and will be taking the car back to dealer next week for them to have a look. This just isn't right. The attached image was a charge yesterday from 12% to 100%..... Only gaining 21.8kWh.

Thankfully there is no Covid here in NZ, so getting this looked at is life as usual...... But a pain regardless.

 

[shikoku14]

That sounds like there may be a faulty cell in the pack that is limiting access to the full pack capacity, I’ve not seen this before in MGs but (as a former Leaf owner myself) have seen this kind of behaviour on older 24 and 30kWh Leaf packs.

Hope MG NZ get you sorted soon, and please keep us update, always worth pooling issue knowledge so other users can self troubleshoot.

 

[sbwithers]

Agreed. It looks like a faulty cell. The limit seems to be 27kWh. There is also some discussion on Facebook that the battery heating update broke the BMS and this 27kWh 'limit' is a consequence of that. Hopefully they will just be able to remove that update........and we can test it from there.

 

[Peter WA]

Did you make any progress with your warranty claim in the meantime?

I am about to buy a ZS EV (in Australia), the only thing holding me back is the fear of being left in the rain with a low capacity battery and no help from the manufacturer, as has happened to Nissan Leaf owners a few years back.

 

[Mhb]

I was having the same problem and I phoned my dealership and they said that since the comfort update was done the car adjusts the mileage range to your driving style. I have since reset the display for the miles per Kw and the range has shot back up again

 

[Graham King]

I was having the same problem and I phoned my dealership and they said that since the comfort update was done the car adjusts the mileage range to your driving style. I have since reset the display for the miles per Kw and the range has shot back up again

This is true but would not explain why the vehicle is only accepting 27kWh in charge...

 

[AussiePete]

Graham, there are discussions here in the UK about an MG recognised issue with a mid 2020 BMS software update that appears to be marking batteries as charged when they are not. Symptoms appear to be gradually reduced range and battery voltage when fully charged bring under 440v.

I can't find the specific thread, however if your battery level is lower than 454v after a full charge and rebalance then it's possible you have this issue.

You need to progress with your dealer and use the full charged battery voltage as the explanation of what's wrong

 

[Graham King]

Graham, there are discussions here in the UK about an MG recognised issue with a mid 2020 BMS software update that appears to be marking batteries as charged when they are not. Symptoms appear to be gradually reduced range and battery voltage when fully charged bring under 440v.

I can't find the specific thread, however if your battery level is lower than 454v after a full charge and rebalance then it's possible you have this issue.

You need to progress with your dealer and use the full charged battery voltage as the explanation of what's wrong

Indeed - that is something for @sbwithers to check out and confirm.
Fortunately, I am not having any issues with the range on my vehicle (getting a consistent 285-290 km at the moment in my environment).

 

[Jeps]

I had the BMS update done in the beginning of December. To me every thing seemed Okey, until I saw some mention that they had lost range after that update. We drive normally mostly short trips so I don't pay that close attention to the range, but after reading about a maybe faulty update, I payed more attention to how much range was used compared to how long we drive. And then I started to see the range dropped faster then I had expected compared to most of our driving is town driving with 50-70 km/h.
Then suddenly just out of nowhere this Monday, I get a call from my MG dealer here in Denmark, they wanted me to come in and have a new update because my previous update was the faulty one.
So today I had the update done (fast delivery I must say ) I was told that the next 14 days I should try to rebalance the Battery by slowcharging as often as possible so the battery/BMS could bring it self back to how It should be.
Now time will tell.
Ps. With the first update I noticed the regen on level 3 got a little weaker, but that seemed now to be back to where I like it be, strong.

 

[Mike]

 

[Mike]

What the first 10 minutes or so.

MG EVs Podcast Monday 18th January 2021 @ 7:30pm UTC

Join MG EV owners for advice about the car plus ask your questions live. Please reply below with any questions or suggestions for discussion topics. Potential topics of discussion: MG5 roof rail update ZS EV BMS update Condensation inside the ZS EV Home chargers - which to choose and why? And...

www.mgevs.com

 

[Jeps]

Just had my first full charge after the BMS update. I started from 8% and had the car charging over night, in the morning I was surprised to see the car was still charging after 16 hours at a 3,7 kw wallbox. I was curious to see how the SOC was showed on the dashboard, but to my surprise the car showed 100% and had stopped charging, but my wallbox was blinking like it normally will do when it is charging. So that was a little bit surprising that the wallboxed looked like it was still charging.
Last full charge before update showed 186 km range in normal mode.
After update the GOM showed 246 km. I don't expect that to be my range in winter time, but I hope to get close to about 200 km.

 

[Cocijo]

following a charge the batteries may start equalisation which ensures a consistent charge across the batteries. This sounds like what you’re experiencing. Good to hear that the update seems to work now anyway.

 

[Mike]

Just had my first full charge after the BMS update. I started from 8% and had the car charging over night, in the morning I was surprised to see the car was still charging after 16 hours at a 3,7 kw wallbox. I was curious to see how the SOC was showed on the dashboard, but to my surprise the car showed 100% and had stopped charging, but my wallbox was blinking like it normally will do when it is charging. So that was a little bit surprising that the wallboxed looked like it was still charging.
Last full charge before update showed 186 km range in normal mode.
After update the GOM showed 246 km. I don't expect that to be my range in winter time, but I hope to get close to about 200 km.

Your car has a duff BMS. Ignore the GOM. What is the voltage when it is at 100%? If it’s around 455V you should still have reasonable range, but you have the duff BMS with the long equalisation session. Mine has taken 6+ hours of the MG badge glowing before it has finished balancing the cells. It should only take up to an hour.

If your voltage is lower than 455V, mine is around 445V and others have reported lower, then you have the range reducing BMS and need to get the car updated by your dealer.

 

[Cocijo]

Your car has a duff BMS. Ignore the GOM. What is the voltage when it is at 100%? If it’s around 455V you should still have reasonable range, but you have the duff BMS with the long equalisation session. Mine has taken 6+ hours of the MG badge glowing before it has finished balancing the cells. It should only take up to an hour.

If your voltage is lower than 455V, mine is around 445V and others have reported lower, then you have the range reducing BMS and need to get the car updated by your dealer.

So it looks like this dealer who just updated the car is still providing the buggy bms?

 

[Jeps]

Your car has a duff BMS. Ignore the GOM. What is the voltage when it is at 100%? If it’s around 455V you should still have reasonable range, but you have the duff BMS with the long equalisation session. Mine has taken 6+ hours of the MG badge glowing before it has finished balancing the cells. It should only take up to an hour.

If your voltage is lower than 455V, mine is around 445V and others have reported lower, then you have the range reducing BMS and need to get the car updated by your dealer.

I checked the voltage before I was out for a little drive, It said around 446v.
I was called in to have the BMS updated because the one I had in December was the faulty one. So I hope the one I received yesterday is the correct one. But now I am little confused.
Is there a chance that the voltage will get higher after several charges as I was instructed to do by my dealer?

 

[Mark Holmes]

I checked the voltage before I was out for a little drive, It said around 446v.
I was called in to have the BMS updated because the one I had in December was the faulty one. So I hope the one I received yesterday is the correct one. But now I am little confused.
Is there a chance that the voltage will get higher after several charges as I was instructed to do by my dealer?

It will be the correct update as the others were withdrawn, give the battery time to balance themselves and get back up to level power through the equalisation process.

 

[AbuG]

It supposed to take a handful of cycles of recharge before battery should be back to optimal voltage... Give it a week (or two depending how often you recharge to see)

 

[Jeps]

I am in no hurry, so I see what happens the comming weeks.
I had a short town drive this evening. I started out with 221 km on the GOM. I drove 7,4 km and GOM was on 212 when I was back home. I drive in normal, level 3 regen, heat and fan on level 2 and with AC on.
So to me everything looks fine.

 

[sbwithers]

My MG eZS is still with the dealer (about 10 days now) after they applied the January 19th BMS update. I have their demo car. It has the same issue as mine. The battery is effectively 30-31kWh after 3500km.

I don't know what to think at this point. This isn't what I paid for.