Battery capacity and poor range

[LeoRBK]

Charger dispatches 32kwh to charge the car from 0 to 100%. Charger measures what it supplies and the energy is also measured on my house meter.
I expect a 44.5kwh battery to take 44.5kwh (less a small amount for usable capacity).
32kwh measured at the charger * charging efficiency at the car of say 90% = 27kwh into the battery.

Hello @andymgzs
Please, what is the voltage shown in the trip meter screen at full charge?
What is the range reported by the car at full charge after trip meter A and B are reset?

How did you read 0% charge when you started measurement at home?

Please, have you tried charging at a rapid charger like instavolt and measured the energy input reported?

 

[andymgzs]

0 miles = 0%.

Don’t need to use a 3rd party charger to check energy input. My measurement was robust.
BTW - car also has a fast charge problem and would take about 2 hours + balancing to get 100%. So 6 hours in total. No thanks.

 

[Gadget Geek]

Charger dispatches 32kwh to charge the car from 0 to 100%. Charger measures what it supplies and the energy is also measured on my house meter.
I expect a 44.5kwh battery to take 44.5kwh (less a small amount for usable capacity).
32kwh measured at the charger * charging efficiency at the car of say 90% = 27kwh into the battery.

The problem the calculations is that the battery is not at 0% to start with. A battery at 0% will never work again, which is why there is a buffer to protect it from full discharge.

Also, I'm a little confused by your naming of charging.

Fast charge = 7-22kW AC (7kW in UK)
Rapid charge = 50kW+ DC

 

[andymgzs]

12.5kw!

 

[Gadget Geek]

12.5kw!

Just posting random numbers doesn't really help forum members to understand your problem.

 

[Kithmo]

FWIW Gen 1 usable capacity is 42.5kWh.
So if you are at 0% you should use 42.5kWh plus losses to get to 100%, 32kWh is way too low.
The 0% indicated battery SOC on the car is actually about 2.5% SOC and 100% indicated is about 97%.

 

[andymgzs]

I was answering your point on buffer. A 12.5kwh buffer is 28%.

Tells me MG have severely limited battery capacity.

Ok it fast charges ok at 7kw.
It does not rapid charge ok. Max ever seen 36kw.

 

[andymgzs]

FWIW Gen 1 usable capacity is 42.5kWh.
So if you are at 0% you should use 42.5kWh plus losses to get to 100%, 32kWh is way too low.
The 0% indicated battery SOC on the car is actually about 2.5% SOC and 100% indicated is about 97%.

Yes - battery is screwed. And MG won’t accept it!

 

[bryer]

Yes - battery is screwed. And MG won’t accept it!

Buy an ODB dongle and see for yourself your battery health, that way you'll see what's going on.

 

[bryer]

And the MK2 is hugely different in what way?

Charging worked as advertised etc. No issues what so ever with speed of charge etc. People don't realise that you are only going to get full speeds when batteries are in optimum window.

 

[Gadget Geek]

From EVDATABASE:

"The battery of the MG ZS EV has an estimated total capacity of 44.5 kWh. The usable capacity is 42.5 kWh (estimate). A range of about 135 miles is achievable on a fully charged battery."

If you don't believe the dealership, you need to get an OBD2 and check for yourself. Although I doubt if you will believe that either.

 

[steve1973]

I have been charging at work as it's free noticed today the range went down to 219 instead of the usual 254 anybody think of why this has happened? Changed nothing from my routine. Stayed on charger for a few hours after 100% so don't have a clue. Reset the trip meters afterwards and it went to 259.

 

[Lovemyev]

I have been charging at work as it's free noticed today the range went down to 219 instead of the usual 254 anybody think of why this has happened? Changed nothing from my routine. Stayed on charger for a few hours after 100% so don't have a clue. Reset the trip meters afterwards and it went to 259.

Resetting the trips removes any historical data stored and predicts the range based on the previous data.
Resetting the trips souls give you something closer to the WLTP range ( ish ).
Some owners prefer to leave the historical data and some prefer to reset the trips.
It’s totally a personal choice situation, do what you are comfortable with is my advice.

 

[Lovemyev]

Yes - battery is screwed. And MG won’t accept it!

I can fully understand your frustration regarding to the issues you think have / have not, with your battery pack.
But it’s become a bit of a “Mexican Stand Off” now because the dealer states the pack is fine and you are not convinced at all.
You are 100% convinced that you have had a faulty pack, from day one almost.
And maybe you have ?‍.
But if you really really want to contest their findings, you need more concrete / structured evidence to challenge the dealers findings.
You could either find another MG dealer who would provide you with a simple, detailed SOH report on the whole pack.
It is likely to cost you 1 - 2 hours labour ( wait ) but it will hopefully give you something, or nothing that will proof / disprove your deep concerns.
You could take it to an independent EV specialist who could do the same thing, but MG may try to contest these findings ??.
Unfortunately, being brutally honest here.
MG are not about to replace that whole pack, worth about 8 - 10 grand, just because you “think” it is faulty.
I know that sounds really harsh, but that’s the truth.
You absolutely need some hard evidence to get them to look at this case again.
Even a simple OBD dongle is a simple starting point, if this give the slightest incline that something is not 100% then you have made the first steps to progress your claim.
Oh …… Sorry, did you say the BMS module has already been replaced on this car ?.
Am I right in thinking the BMS module lives INSIDE of the battery case ?.
As it does in most EV’s.
If so, if it has been replaced, what gave them due course to replace it in the first place and therefore, did this necessitate removing the pack to install it ?.
I ask, only because this is a huge job and needs special Techs to carry out this level of EV work.
It’s not something your local dealer would take on to be honest.
As this car on a lease deal, I expect that you consider expediting this is not really worth the bother and I get that entirely !.
In fairness though, I don’t think any EV manufacture is going to replace a whole battery pack without some serious evidence to support this type of work / expense.

 

[DB Go Rex]

Charger dispatches 32kwh to charge the car from 0 to 100%. Charger measures what it supplies and the energy is also measured on my house meter.
I expect a 44.5kwh battery to take 44.5kwh (less a small amount for usable capacity).
32kwh measured at the charger * charging efficiency at the car of say 90% = 27kwh into the battery.

So you are assuming 1% of your battery equals 4.45KWh?

Depends on your SoH of your battery and currently usable.

Given your car is prefacelift I assume it's at least a couple of years old. You need to get the actual SoH and actually capacity confirmed.

Charging losses are likely not the issue.

 

[andymgzs]

1% = 0.445kwh right

 

[bryer]

Bad BMS? Assume the same for all. I’m sure the firmware wasn’t just created for me.

MK 2 - not based on MK 1 experience.

OK I'm going to call you out here.

MK1 has a battery of 44.5kwh with a useable amount of around 42.5kwh. It had a bad firmware released early in 2022 late 2021, which caused some capacity issues. MG acknowledged fault with it, and rectified it. There are 1000's of users of the MG ZS EV Mk1 and hence why it's not one for all as there are 3 or more versions floating about in the wild.

MK2 Standard range has a battery of 51kwh with a useable amount of 49kwh.
MK2 Long Range has a battery of 72.6kwh with 68.3 being useable.

So to say you have a MK2 with 44.5, you're talking rubbish. Clearly just hear to get a kick out of attempting to drag the brand through the mud.

 

[andymgzs]

OK I'm going to call you out here.

MK1 has a battery of 44.5kwh with a useable amount of around 42.5kwh. It had a bad firmware released early in 2022 late 2021, which caused some capacity issues. MG acknowledged fault with it, and rectified it. There are 1000's of users of the MG ZS EV Mk1 and hence why it's not one for all as there are 3 or more versions floating about in the wild.

MK2 Standard range has a battery of 51kwh with a useable amount of 49kwh.
MK2 Long Range has a battery of 72.6kwh with 68.3 being useable.

So to say you have a MK2 with 44.5, you're talking rubbish. Clearly just hear to get a kick out of attempting to drag the brand through the mud.

Didn’t say I had a MK2!

 

[bryer]

Didn’t say I had a MK2!

Read what you said and I'll quote it again "MK2 - not based on MK1 experience". You've never answered the direction question from users about what model you have, you just keep saying 44.5kwh and arguing with people when they've asked you.

 

[Gadget Geek]

I think we've wasted enough of our time on this one. Just ignore him.