• We are having a problem with new Hotmail members being unable to receive activation emails. Please avoid using a Hotmail email address. Thanks.

Battery capacity

Chrissunray

Standard Member
Joined
Jan 18, 2021
Messages
15
Reaction score
10
Points
5
Location
Ayr
Looking for some assistance:

I’ve had my MG ZS EV since December 2020 and got the latest BMS update on the 22nd February, however I’ve noticed that no matter what charger I use, my battery never seems to charge past 31kwh. For example, the remaining range on my car was between 10-15 miles, then after using the rapid charger it put in 28kwh. I then took my car home and put it on my home charger it only put in 3kwh and did a full equalisation.

I was under the impression that the usable battery capacity was in the region of 40-42.5kwh and that the rapid charger would charge the battery to 80% capacity, so in theory I should be able to get the remainder done on the home charger?

I find that as a result of this my actual physical driving range is rather low given what is originally displayed on the dash.

Is anyone else experiencing this, or is there anything I can do?

Any help/advice is greatly appreciated.
 
What’s your voltage when ‘100%’ charged?
 
The latest bms should show around 450v. Some severely affected cars can take a while to recover and need quite a lot of equalization charges. Yours seems to be quite badly effected. A rapid will charge past 80 it just slows down after that. You only need to get battery down to around 95% before you can charge and equalize again if that helps.
 
Oh. Equalization should be done on 3.5 or 7kw AC chargers. What range are you getting?
 
If your voltage is 440V I don't think you should be "that" badly affected....
@Cocijo what do you reckon at that voltage must be only a few kWh down on maximum? not like 10kWh or something else the voltage would be lower?

You definitely need a few battery charge cycles I'd guess though to get it back to full (450V).

If you're not sure, I'd suggest maybe take it back to the dealer and say; I don't seem to be getting near a proper full charge, please can you stick it on your charger and see if you get more like a proper full charge of 450V.
 
I worked it out to approx 1to 2kwh usable capacity lost based on the 450v being useable 42.5kwh. So down to about 41kwh usable. Should still see around 120miles range. The issue is the equalisation time it will take to get voltage back up of course.
 
Think probably back to the dealer might be the best solution as I’ve already done a few equalisations and the voltage isn’t changing. Do you know how many equalisations I’d need to do to get the voltage back to what it should be?
 
Yes. I think it might be best. Has your car had a life of rapid charging because on the duff bms this can make the cells worse? The 10v you are down may be losing you up to 10kwh in capacity. Each cell only equalises very slowly and transfers mv across affected cells in the pack - some have calculated this at hundreds of hours equalisation needed. Sorry I cannot give you more positive comments 😕
 
Yes. I think it might be best. Has your car had a life of rapid charging because on the duff bms this can make the cells worse? The 10v you are down may be losing you up to 10kwh in capacity. Each cell only equalises very slowly and transfers mv across affected cells in the pack - some have calculated this at hundreds of hours equalisation needed. Sorry I cannot give you more positive comments 😕
That could possibly account for the drop in the battery capacity although been mixing up the charging between rapid chargers and 22kwh ones. I’ll get in touch with the garage on Monday but thanks for your help.
 
Another disappointed customer..This weekend I set out to do a 51 mile journey, starting with 141 miles on the GOM. Arrived at my destination with only 54 miles left. All motorway, speed 60-65mph, no heater etc.

When returning, I had hoped to cover the next 20 miles to a motorway rapid charger, but only just got there with some 4% left on the battery. And then another car was using the rapid, so I used the 7Kw charger until he left. I then charged up to 80%, the GOM showing some 116 miles. The final leg home was only 30 miles, arrived home with 49 miles on the clock, using a one bar of heater occasionally. Temps were about 4'C.

Something not right there at all.

The car is going for an update to software this week, and not too soon.

Patience is wearing a bit thin to say the least..........Grrrrrrr
 
Another disappointed customer..This weekend I set out to do a 51 mile journey, starting with 141 miles on the GOM. Arrived at my destination with only 54 miles left. All motorway, speed 60-65mph, no heater etc.

When returning, I had hoped to cover the next 20 miles to a motorway rapid charger, but only just got there with some 4% left on the battery. And then another car was using the rapid, so I used the 7Kw charger until he left. I then charged up to 80%, the GOM showing some 116 miles. The final leg home was only 30 miles, arrived home with 49 miles on the clock, using a one bar of heater occasionally. Temps were about 4'C.

Something not right there at all.

The car is going for an update to software this week, and not too soon.

Patience is wearing a bit thin to say the least..........Grrrrrrr
@mj224
Sorry for your bad experience with the GOM. I hope it does not put you off electric cars.
I am doubtful that there is anything major wrong with your ZS EV. Basically any EV with a less than 50kWh battery will behave similar to what your ZS did in the recent cold weather we had.
I have tried to objectively explain how the GOM works and why one should not expect to drive the exact mileage shown on the GOM when one starts a journey. Unfortunately my efforts were thwarted by those claiming the ZS EV could do miraculous mileage of above 200 miles driving at motorway speed.
I would not go over the workings of the GOM and what is realistic Range again because last time I tried to humbly explain it resulted in racist and dehumanising abuse from a selected few. I just would ask that you look at real life data for all EVs especially in cold weather and consider adjusting your expectations of the ZS EV. Remember it is the cheapest and most low tech electric SUV on the UK market.
Cold weather does havoc with the performance of lithium ion batteries and the smaller the battery capacity the worse the effect of the cold.
Untill more advanced battery temp control systems and large capacity batteries over 72kWh become the basic standard for EVs, range expectations will be modest.
 
Looking for some assistance:

I’ve had my MG ZS EV since December 2020 and got the latest BMS update on the 22nd February, however I’ve noticed that no matter what charger I use, my battery never seems to charge past 31kwh. For example, the remaining range on my car was between 10-15 miles, then after using the rapid charger it put in 28kwh. I then took my car home and put it on my home charger it only put in 3kwh and did a full equalisation.

I was under the impression that the usable battery capacity was in the region of 40-42.5kwh and that the rapid charger would charge the battery to 80% capacity, so in theory I should be able to get the remainder done on the home charger?

I find that as a result of this my actual physical driving range is rather low given what is originally displayed on the dash.

Is anyone else experiencing this, or is there anything I can do?

Any help/advice is greatly appreciated.
@Chrissunray
I have been working round the data you have given but not sure if I have understood the data.
Now the issue of "charging up to 31 kWh only" how are you measuring that?
Are you using your GOM? Is it by distance travelled or by the energy used per distance travelled?
Also when you say "the rapid charger only put 28 kWh in"........ did the rapid charger automatically cut out after 28kWh or did you stop the charger yourself? And did the rapid charger screen show 80% full?
In any case if the car was not behaving this way before the update then it needs to go back to the garage.
 
Yes. I think it might be best. Has your car had a life of rapid charging because on the duff bms this can make the cells worse? The 10v you are down may be losing you up to 10kwh in capacity. Each cell only equalises very slowly and transfers mv across affected cells in the pack - some have calculated this at hundreds of hours equalisation needed. Sorry I cannot give you more positive comments 😕
Had a lot of problems after the BMS update in early December - the range dropped about 100 km - the real range after the update remained about 140 km only. Every day - multiple warnings "Slow Charge the Vehicle" although I have slow charged the vehicle almost every night.
The point is that after that the dealership replaced the faulty BMS update, it took them 21 days of charge/empty cycles to get the car back to normal.
 
@Chrissunray
I have been working round the data you have given but not sure if I have understood the data.
Now the issue of "charging up to 31 kWh only" how are you measuring that?
Are you using your GOM? Is it by distance travelled or by the energy used per distance travelled?
Also when you say "the rapid charger only put 28 kWh in"........ did the rapid charger automatically cut out after 28kWh or did you stop the charger yourself? And did the rapid charger screen show 80% full?
In any case if the car was not behaving this way before the update then it needs to go back to the garage.
When I put it on the rapid charger it showed on the charger screen that my battery pre charging was approximately 6% and once it finished charging it showed 28kwh on the screen. My car dash also had the message charging complete. Then when I took it home and used the home charger which displays the usage on the app, it showed 3kwh went into the battery after around 4 hours of charging (obviously this includes equalisation).

Prior to the update, we were finding a similar issue which I think has got worse over time and the range has been rather unpredictable, especially when the range is showing 140 ish and we’re only completing a 70 miles round trip, with heating off and outside temperature around 9 degrees celsius, the final range shows 16 ish miles left and just can’t help but think this is due to the car not utilising the full battery capacity when allegedly charging to full.
 
When I put it on the rapid charger it showed on the charger screen that my battery pre charging was approximately 6% and once it finished charging it showed 28kwh on the screen. My car dash also had the message charging complete. Then when I took it home and used the home charger which displays the usage on the app, it showed 3kwh went into the battery after around 4 hours of charging (obviously this includes equalisation).

Prior to the update, we were finding a similar issue which I think has got worse over time and the range has been rather unpredictable, especially when the range is showing 140 ish and we’re only completing a 70 miles round trip, with heating off and outside temperature around 9 degrees celsius, the final range shows 16 ish miles left and just can’t help but think this is due to the car not utilising the full battery capacity when allegedly charging to full.
You need the BMS Jan15th 2021 update A.S.A.P.
You longer you continue with the “Buggy” software and the more you charge, the worse your battery range will get and the longer it will take to rebalance the pack.
 
You need the BMS Jan15th 2021 update A.S.A.P.
You longer you continue with the “Buggy” software and the more you charge, the worse your battery range will get and the longer it will take to rebalance the pack.
I got the new update on the 22nd February and have only had the car since December so will not be happy if I get told I need to do hours upon hours of equalisations to get the battery back to what it was when I bought the car - It’s so frustrating as the car is so lovely to drive.
 
You need the BMS Jan15th 2021 update A.S.A.P.
You longer you continue with the “Buggy” software and the more you charge, the worse your battery range will get and the longer it will take to rebalance the pack.

Yes in my case, i have done the 102 mile round trip several times over the last couple of months.

The first time, the car came home with 30 miles in the tank, the second time, I had to recharge at about 70 miles, and last night I had to recharge at about 80 miles. When I say had too, I HAD to with 4% of the battery left.

So I do feel the range is getting worse, fully charged voltage is 440v or so. As said the car is going to have its update this week...
 
Support us by becoming a Premium Member

Latest MG EVs video

New EVs from MG: MG S9 & MG9 plus hot topics from the forums
Subscribe to our YouTube channel
Back
Top Bottom