Battery degraded by approx. 20 miles in 10 months

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djr

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MG ZS EV
Hi all,

I bought my 44.5 kWh ZS EV (2020 model) about 10 months ago and last Summer I charged it a several times using a fast charger (BP Pulse) and achieved figures like 148 miles and 152 miles at 100% capacity.

During the Winter months I didn’t travel very far so tended to just top up with 20-30 miles using the granny charger plugged into the mains in the garage.

Today I went to my first fast charger in a while (Instavolt) and fast charged to 100% capacity, but the display inside the car only showed 128 miles, so I have a few questions:
1. Has my battery degraded by 20 miles in the last 10 months?
2. If I went to a different fast charger would I see any difference?
3. Should I get the dealer to check the battery in the hope that they can improve the capacity?
4. If this repeats next year will the capacity go down to 108miles?
 
Last edited by a moderator:
One question . You say fast charger , do you mean 7 or 22kW ? or a rapid charger 50kW or above ( which is what I assume by Instavolt ) .
Repeated rapid charging to 100% is not recommended for battery health and frankly pointless as the charging rate drops after 80 %
 
Last edited by a moderator:
If it was an Instavolt, it was 350 kW DC.

So even though it was taken to 100%, it seems the pack wasn't balanced. @djr, what you need to do if you can't wait for it to go all the way on the granny charger is to take the car up to maybe 90% on the DC charger then take it home and let it go the rest of the way on the granny charger, then sit there for as long as it takes for the pack to balance. (You can probably tell from the app that this has happened, but ask in the ZS forum for details.)

This may actually improve the range estimate that you get. Also recommended is to run the car down to below 10% then let it charge all the way up to 100% and balance on an AC charger of some sort. This should be done every 3 to 6 months and will improve the accuracy of the GOM and reduce the chances of nasty surprises if you run the car low on a long trip.
 
Last edited by a moderator:
djr said:
Hi all,

I bought my 44.5 kWh ZS EV (2020 model) about 10 months ago and last Summer I charged it a several times using a fast charger (BP Pulse) and achieved figures like 148 miles and 152 miles at 100% capacity.

During the Winter months I didn’t travel very far so tended to just top up with 20-30 miles using the granny charger plugged into the mains in the garage.

Today I went to my first fast charger in a while (Instavolt) and fast charged to 100% capacity, but the display inside the car only showed 128 miles, so I have a few questions:
1. Has my battery degraded by 20 miles in the last 10 months?
2. If I went to a different fast charger would I see any difference?
3. Should I get the dealer to check the battery in the hope that they can improve the capacity?
4. If this repeats next year will the capacity go down to 108miles?
Click to expand...
Whilst at 100% turn off all heating etc and reset the Accumulated trip. Then look at the GOM to check for any degredation.
 
djr said:
Hi all,

I bought my 44.5 kWh ZS EV (2020 model) about 10 months ago and last Summer I charged it a several times using a fast charger (BP Pulse) and achieved figures like 148 miles and 152 miles at 100% capacity.

During the Winter months I didn’t travel very far so tended to just top up with 20-30 miles using the granny charger plugged into the mains in the garage.

Today I went to my first fast charger in a while (Instavolt) and fast charged to 100% capacity, but the display inside the car only showed 128 miles, so I have a few questions:
1. Has my battery degraded by 20 miles in the last 10 months?
2. If I went to a different fast charger would I see any difference?
3. Should I get the dealer to check the battery in the hope that they can improve the capacity?
4. If this repeats next year will the capacity go down to 108miles?
Click to expand...
There have been independent tests and they concluded that a normal battery pack being charged an average amount of times each year, woukd lose 1 to 2% of its capacity each year. That sounds a lot but on a car with an average range of 200 miles per charge that would mean at most 2 to 4 miles a year.

Independent tests have concluded that battery packs on an EV would last for between 1,500 and 2,000 full cycles (0 to 100%)
That is the equivalent of over 300,000 miles.
In general they are likely to outlast the car itself!
Seriously! Check for yourself.
 
Hi all,

Thanks for all of your fantastic advice. I don’t regularly charge to 100% on a rapid charger, only about 5 times in 10 months that I've had the car.

Thanks @Rolfe for the tip about charging to say 80% on a rapid charger and then charging the remaining 20% at home, this makes good sense.

A few of you have mentioned 'balancing the batteries', which is something I didn't know about until now, so I'll have a read through this link:

MG ZS EV Battery charging and balancing

Hi I've just discovered this forum and I'm looking forward to learning more about my car. I picked up a 2020 MG ZS EV Exclusiv last week. It's my first EV. We've had a few teething problems trying to get it charged but I think we're getting there now. But after looking through some previous...
www.mgevs.com www.mgevs.com
to make sense of it all.
 
With an NMC battery (which I assume you have) you should aim to do that about once a month, preferably shortly before you intend to run the battery back down below 80%, to save leaving it at a high SoC for too long. This will maximise your range, and also help the GOM give you an accurate estimate.
 
djr said:
Hi all,

Thanks for all of your fantastic advice. I don’t regularly charge to 100% on a rapid charger, only about 5 times in 10 months that I've had the car.

Thanks @Rolfe for the tip about charging to say 80% on a rapid charger and then charging the remaining 20% at home, this makes good sense.

A few of you have mentioned 'balancing the batteries', which is something I didn't know about until now, so I'll have a read through this link:

MG ZS EV Battery charging and balancing

Hi I've just discovered this forum and I'm looking forward to learning more about my car. I picked up a 2020 MG ZS EV Exclusiv last week. It's my first EV. We've had a few teething problems trying to get it charged but I think we're getting there now. But after looking through some previous...
www.mgevs.com www.mgevs.com
to make sense of it all.
Click to expand...
I think the other thing to do prior to charging is to reset your car’s mileage stats as these are used in the GOM calculations and as I understand it can affect the final values after a charge/balance.
It’s the one thing I always forget to do…
 
Spinynorman said:
I think the other thing to do prior to charging is to reset your car’s mileage stats as these are used in the GOM calculations and as I understand it can affect the final values after a charge/balance.
It’s the one thing I always forget to do…
Click to expand...
Resetting the counters just defaults the GOM to the factory default value. For a realistic, real world range based on your driving, leave them be.
 
djr said:
Hi all,

I bought my 44.5 kWh ZS EV (2020 model) about 10 months ago and last Summer I charged it a several times using a fast charger (BP Pulse) and achieved figures like 148 miles and 152 miles at 100% capacity.

During the Winter months I didn’t travel very far so tended to just top up with 20-30 miles using the granny charger plugged into the mains in the garage.

Today I went to my first fast charger in a while (Instavolt) and fast charged to 100% capacity, but the display inside the car only showed 128 miles, so I have a few questions:
1. Has my battery degraded by 20 miles in the last 10 months?
2. If I went to a different fast charger would I see any difference?
3. Should I get the dealer to check the battery in the hope that they can improve the capacity?
4. If this repeats next year will the capacity go down to 108miles?
Click to expand...
Bought in the summer!! It's now colder weather, the cold temperatures will make a big difference (lower) to battery capacity, try it again when it a lot warmer and let the group know!
 
Gadget Geek said:
Resetting the counters just defaults the GOM to the factory default value. For a realistic, real world range based on your driving, leave them be.
Click to expand...
It resets it to WLTP based on a 100% state of health (SOH). If the SOH has reduced this will reflect in the GOM when the accumulated trip is reset and mode is Normal, with everything else such as heater set to off.
So as an example if WLTP for car is 250 for the long range model then if the reset GOM show 245 then it indicates your SOH to be 98%.
For real world range, totally agree just leave them be.
 
Gomev said:
It resets it to WLTP based on a 100% state of health (SOH). If the SOH has reduced this will reflect in the GOM when the accumulated trip is reset and mode is Normal, with everything else such as heater set to off.
So as an example if WLTP for car is 250 for the long range model then if the reset GOM show 245 then it indicates your SOH to be 98%.
For real world range, totally agree just leave them be.
Click to expand...
That makes sense . I followed this procedure after my last service and the range was 246 miles (LR) .Yet the service sheet said my SOH was 90% .
I'm going with your assessment ;)
 
maskull said:
That makes sense . I followed this procedure after my last service and the range was 246 miles (LR) .Yet the service sheet said my SOH was 90% .
I'm going with your assessment ;)
Click to expand...
Just make sure you were in normal mode not eco. :)
 
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