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Looking at the GOM is meaningless, your calculation is flawed that’s why
Whilst you're correct in stating the GOM is meaningless, it doesn't help the O/P in answering the question!

There's losses in the charging system, but even if you assume 5% loss, and then also factor in that the stated 10 miles left was drastically understating the true remaining miles possible (and therefore the actual percentage power remaining), there can't have been 10kW available, so it's clear if only 24kWh can be put into the battery, then it's not able to provide the full 44kW.

To address the issue, I'd run the battery closer to empty, then see how much energy can go into the battery. And if there's still an issue, then raise it with the dealer.
 

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Renault Zoe 50
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It’s very cold in the UK, so the GOM is probably factoring in heating use as well as the lower voltage due to battery temp.
 

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If you watch the GOM and turn on the heating and seats and full beam lights, you'll see the range drop. Switching from sports to eco makes a big difference.
The other day I made a delivery and was running late, doing a true 70mph, where legal, dropped my efficiency to just 2mi/kWh. On the way back, letting my speed drop to true 65, the average rose to 2.6 so just for the second leg it would have been maybe 3.
 

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None of these comments are taking into account the broken BMS though. The cars with it are are really rather debilitated in terms of range until they’re updated and then balanced several times.

OP - I’m not sure you’d be able to reject the car because the rebuttal from the dealer will be that they’ve fixed it but I do wonder if you could shift the requirement for lots of charging and balancing onto them, insisting on a courtesy car whilst they’re sorting it.
 

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MG warrant 70% capacity for 7yr/80k miles.

Mine would take ~45.5kWh to fill from 0-100% (calculated from various levels of discharge)

Allowing for c.10% AC ->DC loss suggests actual usable capacity was more like 41kWh.

Before the latest update I measured 31kWh gross to charge 0-100% (starting from 3%)

That's 68% original capacity.

It's slowly rising with every balance charge. Very slowly.

OVMS data from those who have the gear suggest the cells will evevtually all recover.

OP's charging data looks worse than mine was - his car may be below the warranted level for months, even with his best efforts and the added expense and hassle of balancing charges (draws 300W for up to 12 hours, each time)

Considering some customers have had a ballache trying to get a 12V battery replaced FOC within a year, I have precious little faith in MG/MGUK honouring its warranty claims without having to pull teeth.

Step one, I guess, is to make the dealer aware of the issue, your disappointnent in the failure of the product, and a satisfactory outcome for yourself. Some affected customers have been offered a free seevice if that helps.
 

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Thanks for the replies so far. For clarity, I always drive in eco mode as I wouldn't get to work and back in sports mode! In my example above, with 10 miles remaining- this was in eco mode, with the heater/fan off. The car wouldn't go above 20% power so I don't accept the claim that there was more than 10 miles left in the battery. If there was, it was unusable.with only 20% power available..
I have had the GOM down to --miles but the battery charge still only took 25kWh and again the car wouldn't go above 20% power.

'Mrmoonuk' -if my calculation is flawed, could you offer a different calculation or any helpful advice??.. when the car shows --miles and you only get 20% power, how far would you drive to deplete the battery further (and going uphill I cant get above 30mph). This is after approximately 65miles of driving, so really my last '10miles' isn't safely useable unless in a 30-40mph speed limit. 30mph on a motorway isn't safe - the car wouldn't go faster.
Once the battery is low like that, park in front of your charger, then leave the car in park, put the heater on max and roll down the windows and leave it for an hour, then check every 15 minutes or so. This will get it completely empty and give the BMS accurate data about where the bottom is.
 

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30KW Tekna (2017)
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Do you have a battery Leafspy equivalent? Any chance in a week cell or two dragging the pack down and locking in the last few kw? Thats the fault I had with my leaf and I remember being stood at the rapid scratching my head as to why it had only drunk 15KW to full from empty
 

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Zoe Devotee
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What worries me most about the new "fixed" BMS is some have said it can be as many as 50 charges to get the pack balanced and back to where it was before the broken BMS. Now by 50 charges I believe the poster meant 50 cycles, which in my case is easily going to be a years worth of motoring, a YEAR! To recover from an MG made mistake? I'd be expecting compo definitely. Most folk can't go a week without their car when its broken, but this admission is that your car will be sub-par for potentially 12 months takes the biscuit. Especially as the long term "fix" is to rebalance every time, in some cases this will be wasting literally hundreds of pounds of electricity that your paying for, not MG.

I'm only glad I've learned the hard lesson after following the sheeple pack in getting my Zoe updated. Wait a year after a major update, by then things like this issue are coming out the woodwork.
 
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Once the battery is low like that, park in front of your charger, then leave the car in park, put the heater on max and roll down the windows and leave it for an hour, then check every 15 minutes or so. This will get it completely empty and give the BMS accurate data about where the bottom is.
And record how much juice goes in from your charger or smart meter.
 

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ID3 1st & e-Golf
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How about talking to them about the pack being below the 70% warranty level and the car not being usable for your daily driving needs in its current state.
That's where I would start as it doesn't sound like it's meeting the 70% level.
It should be up to them to sort it, not for you to wait for it to recover.
 

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What rights do I have if my range doesn't increase? The car was sold as 44kWh and it currently isn't even close to that. The car was new when we bought it 4 months ago and it now has around 5000miles on the clock.
The same rights as any other purchase under the Consumer Rights Act 2015.
  • Within the first 6 months from taking ownership, the assumption is that any problems were always there, after 6 months, the burden of proof moves to you. If you're going to complain, complain quickly and in writing to get in before the 6 month deadline.
  • You have the right to ask for a repair or replacement. You cannot mandate which happens, it is up to the retailer do choose. If the repair or replacement also fails, you are allowed a refund.
I don't intend going into the dealership 'all guns blazing', but I feel like I have been sold a lemon
This is the correct approach - there is a very fine line between being firm and being a dick. Within the first 6 months, the dealership must prove that you haven't been sold a lemon. If any action or inaction puts you at a loss, you can pursue reasonable costs (e.g. hire car while they're fixing yours). Keep a record of any costs incurred, and be prepared to take it to a small claims court if you are dissatisfied. Note that this isn't guaranteed, so pursue costs at your own risk. This also goes the other way, if it turns out that there isn't an issue, you can be pursued for costs.

The key thing to remember is that your contract is with the seller. Don't let them try and fob you off to the manufacturer (unless that is permitted under the terms of sale that you agreed to before taking the car).

The other thing to keep in mind is the person at the service desk probably isn't paid enough to get shouted at. Don't be afraid to escalate.
 

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2020 VW ID3 Life 58kWh
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I think you'd be right to go back to your dealer and raise this as an issue and ask them what they are going to do about it, as others have said be firm but polite and make sure you make a record of everything.
 

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Now by 50 charges I believe the poster meant 50 cycles,
Isn't it possible (once the pandemic is over) to go for a few miles and then charge again over night several days and see if that brings the voltage back up. You don't even have to drive it, we sat on the drive the other day having a mug of soup (just to get out of the house. Boy, those 4 walls are getting closer every day) with the heated seats on and the heater as well. Dropped about 10 miles before we'd finished.
 

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My car has the buggy BMS software and is going to be updated soon. I accept that my range will be somewhat reduced from the claimed 160miles due to cold/wet/windy weather, however I am currently getting 75-80miles range
My fully charged and balanced battery is only 437volts and it doesn't hold 44kWh. Not even close.
With 10miles left on the GOM (based on my average of 2.7miles/kWh, that is approximately 4kW remaining in the battery.
A 'full' charge from 10miles remaining and it only took 24kWh, therefore my battery capacity is approximately 28kWh.
(This is the case every evening when I charge it - smart meter and my charger app show the same data).

Having read about the BMS update, it looks like it might take dozens of charges to bring the battery voltage up to where is should be (assuming that the update actually works..) - so possibly months of waiting to see if my car will have a reasonable range and/or if it will actually hold close to 44kWh.

I accept that mistakes happen, however I need my car for work and my current 75-80mile range only just allows my work based mileage, but if I need to make a journey after work I have to use my wife's diesel car. In a few years time when the battery starts to 'degrade', the car won't be useable for my work purposes unless the BMS update works..

What rights do I have if my range doesn't increase? The car was sold as 44kWh and it currently isn't even close to that. The car was new when we bought it 4 months ago and it now has around 5000miles on the clock.

I don't intend going into the dealership 'all guns blazing', but I feel like I have been sold a lemon - we had been looking to buy an electric car for a long time - cost and range was prohibitive until the ZS arrived. A few years back we decided that a 24kWh Nissan leaf wouldn't work for us due to it's limited range, but I now have a 28kWh ZS instead....:mad:
My car has the buggy BMS software and is going to be updated soon. I accept that my range will be somewhat reduced from the claimed 160miles due to cold/wet/windy weather, however I am currently getting 75-80miles range
My fully charged and balanced battery is only 437volts and it doesn't hold 44kWh. Not even close.
With 10miles left on the GOM (based on my average of 2.7miles/kWh, that is approximately 4kW remaining in the battery.
A 'full' charge from 10miles remaining and it only took 24kWh, therefore my battery capacity is approximately 28kWh.
(This is the case every evening when I charge it - smart meter and my charger app show the same data).

Having read about the BMS update, it looks like it might take dozens of charges to bring the battery voltage up to where is should be (assuming that the update actually works..) - so possibly months of waiting to see if my car will have a reasonable range and/or if it will actually hold close to 44kWh.

I accept that mistakes happen, however I need my car for work and my current 75-80mile range only just allows my work based mileage, but if I need to make a journey after work I have to use my wife's diesel car. In a few years time when the battery starts to 'degrade', the car won't be useable for my work purposes unless the BMS update works..

What rights do I have if my range doesn't increase? The car was sold as 44kWh and it currently isn't even close to that. The car was new when we bought it 4 months ago and it now has around 5000miles on the clock.

I don't intend going into the dealership 'all guns blazing', but I feel like I have been sold a lemon - we had been looking to buy an electric car for a long time - cost and range was prohibitive until the ZS arrived. A few years back we decided that a 24kWh Nissan leaf wouldn't work for us due to it's limited range, but I now have a 28kWh ZS instead....:mad:
did you distance buy the car? You may have a right to refund
 

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Zoe Devotee
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Isn't it possible (once the pandemic is over) to go for a few miles and then charge again over night several days and see if that brings the voltage back up. You don't even have to drive it, we sat on the drive the other day having a mug of soup (just to get out of the house. Boy, those 4 walls are getting closer every day) with the heated seats on and the heater as well. Dropped about 10 miles before we'd finished.

Not if its 50 cycles. A cycle being a measure of a full discharge. I mean you charge your mobile phone from 50% to 100% is only 1/2 a cycle not a whole cycle.

Your looking at over 6500miles if your getting 130miles to a charge, in my case I've only covered about 8k in nearly 12months at roughly 160miles a charge, so it would take me until 2022 to get the balance back in check. So glad I stuck with the out of the box BMS from March 2020.
 
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