Battery capacity

[JodyS21]

Oh yes, the Glasgow incident.
Sorry, I forgot.
Hope the car is back soon as good as new.
If the device is not that expensive then it may be worth a go but I have my doubts about the accuracy.

It is reading the data provided by the cars ECUs, I don't quite see how they can be inaccurate, it is the exact same data that is available to the MG technicians. They could of course be misinterpreted.

If you follow the information on this forum, you will see that we know what all the BMS versions are. By reading the obd2 ecu version data, one can very easily see exactly what version of the BMS software you have installed.

 

[macd2401]

Hopefully the more data points we can get, the more confident we can get that it is accurate.

 

[Mg5man]

Mg need to sort out the bms issues fast. Who in there right mind would buy a car with faulty bms which you have to charge possibly 100 times to get it working properly.

 

[Gwyn Wardman]

What is this equalisation that everyone is writing about?

 

[mj224]

I had my January BMS update the other day. Fully charged battery still is only 440 volts. But they did say it will take time to get back to where it should be...:-(

 

[Gomev]

What is this equalisation that everyone is writing about?

@Gwyn Wardman This is the bit after car is fully charged using an A/C (wallbox/granny/7kw) where the BMS spends time trying to balance all the cells in the battery pack so that they are all charged up as much as possible the same.
You need to leave the car plugged in. You can tell it is equalising by the MG badge on the front. The little dots on the badge will be illuminated constantly. When charging the dots 'pulse', when unplugged or not charging/balancing they are not illuminated.

 

[KasEV]

I had my January BMS update the other day. Fully charged battery still is only 440 volts. But they did say it will take time to get back to where it should be...:-(

@mj224
What was you voltage before having the update.
If your voltage was 450 - 455 before the update then you shouldn't be having any problems maintaining about 449-450 after the update and it shouldn't require multiple charges for that to happen.
Are you sure they haven't mistakenly applied the discarded buggy update?
You should keep an eye and go back if the voltage remains low.
Just pulling your legs..
Please let us know how long it takes to recover.

 

[KasEV]

It is reading the data provided by the cars ECUs, I don't quite see how they can be inaccurate, it is the exact same data that is available to the MG technicians. They could of course be misinterpreted.

If you follow the information on this forum, you will see that we know what all the BMS versions are. By reading the obd2 ecu version data, one can very easily see exactly what version of the BMS software you have installed.

@JodyS21 Have you personally got one of these data reader gadgets?
I personally do not trust using a generic reader that claims to be able to read all makes of cars. I have some experience of these units from several years ago. May be over 15 to 20 years ago or more? At the time one was having to buy a different unit for each make of car. So one had one for BMW, one for Ford's etc. Then a company called Launch came along and said guys we have a unit that works on all cars please buy from us. If I remember correctly the experience was not good to start with and we required update after update and it work well with some car brands and rather poorly with others. I must admit I have lost touch with all that sort of stuff in recent years and although from what I gather more recent units from this company called Launch are quite good, my experience from several years ago make me skeptical of cheap small gadgets that claim to be able to do miracles. I am following the discussion on this issue on the forums and I get the impression there is quite a lot of difficulty still with these gadgets.

 

[JodyS21]

@JodyS21 Have you personally got one of these data reader gadgets?
I personally do not trust using a generic reader that claims to be able to read all makes of cars. I have some experience of these units from several years ago. May be over 15 to 20 years ago or more? At the time one was having to buy a different unit for each make of car. So one had one for BMW, one for Ford's etc. Then a company called Launch came along and said guys we have a unit that works on all cars please buy from us. If I remember correctly the experience was not good to start with and we required update after update and it work well with some car brands and rather poorly with others. I must admit I have lost touch with all that sort of stuff in recent years and although from what I gather more recent units from this company called Launch are quite good, my experience from several years ago make me skeptical of cheap small gadgets that claim to be able to do miracles. I am following the discussion on this issue on the forums and I get the impression there is quite a lot of difficulty still with these gadgets.

I got a £12 one.
It’s a simple standard they use to read the data, the very cheap knock off Chinese chip copies may not fully comply with latest standards etc. (Edit, better chips also work faster for better data refresh rates)
If you have a dongle that works then it’s just a matter of knowing which data items are there to request.
All cars have to supply a basic set of data using the same method. After that there’s lots of other manufacturer specific data that can be obtained it’s just a matter of knowing what it is. It’s not that difficult to figure out the more obvious stuff.
It gets complicated when you start updating via obd2, that’s when you need software that’s been developed and tested properly to ensure you don’t brick the ecu - that’s the stuff you pay for.

 

[Bazzer44]

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.

How can you tell its done an equalisation ?

 

[JodyS21]

How can you tell its done an equalisation ?

Watch the MG badge (or put a camera on it - my security camera catches it!), how ever long it is on constant means that's how long it's trying to balance for.
In terms of ACTUALLY DONE a balance vs TRYING, only way would be get obd2 dongle (or ovms) and monitor the min/max cell voltages when it's finished charging and then when it's finished balancing....

 

[mj224]

@mj224
What was you voltage before having the update.
If your voltage was 450 - 455 before the update then you shouldn't be having any problems maintaining about 449-450 after the update and it shouldn't require multiple charges for that to happen.
Are you sure they haven't mistakenly applied the discarded buggy update?
You should keep an eye and go back if the voltage remains low.
Just pulling your legs..
Please let us know how long it takes to recover.

My voltage at full charge was 439v, after or so, its almost 440v, so some time to go I feel................:-(