Signs of a(n) (un)healthy battery in a Used MG4

[HazardLights]

Hi,

I have been looking at used MG4s but have just realised that I am measuring their battery health largely on mileage and thought that this is possibly insufficient therefore I would like to hear your sage advice...

How should one measure battery health when buying an MG4?
Practically how is this done?
What is healthy for a 1-3 year old car battery that has been doing 8k miles per annum?

Thanks,
HazardLights

 

[MG4 Aussie owner]

Hi,

I have been looking at used MG4s but have just realised that I am measuring their battery health largely on mileage and thought that this is possibly insufficient therefore I would like to hear your sage advice...

How should one measure battery health when buying an MG4?
Practically how is this done?
What is healthy for a 1-3 year old car battery that has been doing 8k miles per annum?

Thanks,
HazardLights

Possibly related: this post (software updates solved my range issue).

 

[siteguru]

Hi,

I have been looking at used MG4s but have just realised that I am measuring their battery health largely on mileage and thought that this is possibly insufficient therefore I would like to hear your sage advice...

How should one measure battery health when buying an MG4?
Practically how is this done?
What is healthy for a 1-3 year old car battery that has been doing 8k miles per annum?

Thanks,
HazardLights

State of Health of the HV battery should be recorded at every service, so check the service record. At the first service last November the garage recorded the SoH of mine as 95%, which is not unexpected for the LFP pack as it has very little buffer. I'm expecting the SoH at the next service to be very similar, as the LFP pack is known to show degradation in the first year then it flattens out for the next few years.

(Batteries with a big buffer essentially mask the degradation for the first few years).

 

[Anon70]

Any MG dealer should be able to provide you with a high voltage battery capacity check and the warranty covers you for for the battery holding at least 70% of its original capacity for 7 years. This assumes the car has been maintained to manufacturers specs.

The thing you won't know is the last time a recalibration charge took place as this can impact what the GOM is showing (as well a ambient temp and efficiency of the most recent journeys).

In a similar vein, you could ask when buying an ICE car did you check the engine output in HP and compare that to the original spec when new. Also how bothered were you by the mpg compared to manufacturer specs and how did you check this?

 

[HazardLights]

In a similar vein, you could ask when buying an ICE car did you check the engine output in HP and compare that to the original spec when new. Also how bothered were you by the mpg compared to manufacturer specs and how did you check this?

I am new to buying used cars after a life of buying new and running until 10-11 years old. For ICE cars I would test drive and see if they gave performance similar to what I expect and require. In short, approximate was fine for the ICE car and approximate for battery health is fine for EV.

In this case I am looking to get my first EV and looking to get a used car and given that the history of EVs is short and it's difficult to draw conclusions when the history includes Nissan Leaf without battery management, and cars with other battery chemistries (e.g. NCA). As a first time EV buyer I am aware that I am unsure of the pitfalls and lack the confidence that those who have owned one may have. Perhaps I shouldn't worry about it but my concern is I don't know if a car sitting doing little mileage but plugged into a charger 24x7 is a poor buy.

 

[Rolfe]

I don't think it is a bad buy, unless it's an NMC chemistry that has been held at 100% all the time. If the charge has been limited to 80%, it would be fine. Other than that undesirable scenario, battery lifespan is related to charge/discharge cycles much more than to time, so if a car has low mileage you should be on to a good thing.

 

[okohll]

As people say, it should be fine but also if you do want to check it yourself on the spot you could do so with an app plus a bluetooth dongle to plug into the car. 'Car Scanner' is the standard app, if you search the forum for that, you should see details. A bit of a process to set up but maybe you could test on a friend's car or something first.

If I was buying a second hand EV I definitely would check, just to be sure I wasn't getting one of the minority of lemons, or to compare different cars with each other.

 

[HazardLights]

Thank you all. It sounds like the risks are pretty low but I can do some verification to put my mind at ease. I am trying to postpone my purchase until next year as I will have more cash at hand than I wish next summer but I am champing at the bit!

 

[Rolfe]

It's such a dilemma. Do you jump now and get all the benefits of electric motoring NOW, or do you hold off a bit longer - and a bit longer - and a bit longer - to see if even better benefits are available. At some point you have to get on the train, but that point will be different for every individual.

 

[HazardLights]

It's such a dilemma. Do you jump now and get all the benefits of electric motoring NOW, or do you hold off a bit longer - and a bit longer - and a bit longer - to see if even better benefits are available. At some point you have to get on the train, but that point will be different for every individual.

On the one hand there is my heart obsessing about a shiny new toy and on the other there is my brain saying that I have a lump sum coming next year which is more than I can squirrel away in an ISA. I am not entirely sure which bit will win. Replacing my wife's car with a newer model was supposed to help but it's made it worse as it has shown how much I enjoy shiny new toys. It's like a (siren) song stuck in my head, I probably need professional help I cannot even go test driving them as that will make me worse and be cruel teasing of car dealers.

 

[Anon70]

Totally understand that EV's are a brave new World, I was full of many of the same questions before jumping in, but like Michael McIntyre says "it's all right, once your in". Mostly the fear of the unknown and the misleading press stories

 

[Tight Git]

I was in the same position 2 years ago and changed from a Hyundai i30 1 litre petrol (gutless!) to the SE SR and I've no regrets. 32k miles and the savings on fuel are significant (how I sold it to my wife!).

Would I buy another one - no, because my impending lump sums will have me looking at a Porsche Macan unless I slum it and get a high performance EV6 or Ioniq 5 ??

 

[Rolfe]

Not so tight, then?

I went from "you can't write off my pride and joy just because of a dented door and wing!" to "I totally love my SE SR, thanks to the kindly BMW driver who wrote off my Golf!" in less than two weeks.

 

[Tight Git]

Not so tight, then?

I went from "you can't write off my pride and joy just because of a dented door and wing!" to "I totally love my SE SR, thanks to the kindly BMW driver who wrote off my Golf!" in less than two weeks.

Well no-one to leave it to so I'm going to attempt to spend it all before I pop my clogs!

 

[Bam Bam]

On the one hand there is my heart obsessing about a shiny new toy and on the other there is my brain saying that I have a lump sum coming next year which is more than I can squirrel away in an ISA. I am not entirely sure which bit will win. Replacing my wife's car with a newer model was supposed to help but it's made it worse as it has shown how much I enjoy shiny new toys. It's like a (siren) song stuck in my head, I probably need professional help I cannot even go test driving them as that will make me worse and be cruel teasing of car dealers.

Yeah there are lots of new things aren't there. Rolfe's circular reasoning post set out well that once you've got the car/solar you then want the other one plus home battery. Heat pump also in my case, which is the thing we haven't got yet, for a few reasons, but I feel we should really.

 

[tsedge]

Our new governmental overlords have pledged in their manifesto to create a certification scheme for 2nd hand EVs including clear display of the SOH of the battery.

 

[DevonMG4]

Thank you all. It sounds like the risks are pretty low but I can do some verification to put my mind at ease. I am trying to postpone my purchase until next year as I will have more cash at hand than I wish next summer but I am champing at the bit!

Knowing what I now know! (and I'm unaware of what I don't know). I'd buy sooner rather than later, you'll not regret it and you will be saving fuel costs sooner (assuming you can charge at home).

I'd buy standard range, as from the current state of knowledge the battery will be more tolerant of poor charging practices. I'd buy from a main dealer on the condition they provide a SOH report and they ensure all software updates are applied including the infotainment - an independent will not be in a position to do this for you. They'll also be in a position to ensure the AA cover is in place and centralised service records are up to date.

The MG4 is a great first EV and I'd expect to be paying £15-16k for a 22 plate SE SR from a main agent.

I'm 31,000 miles in and loving it.

 

[MG4 Aussie owner]

Yeah there are lots of new things aren't there. Rolfe's circular reasoning post set out well that once you've got the car/solar you then want the other one plus home battery. Heat pump also in my case, which is the thing we haven't got yet, for a few reasons, but I feel we should really.

I have a 15kW solar panel setup on my roof and 10kWh battery storage. To be completely honest it’s useless for 2 months of the year during June and July (southern winter). But I’m hoping next summer with the money I’ll get by putting in extra power into the grid will pay for all my energy required from the grid during the winter will cover it all (including charging my car) ??

 

[Bam Bam]

Wow - you get 10 good months per year. We are lucky to get 5 on our East-West array in the UK!

In the first year we roughly broke even in March and October. Like you, building up credit for the Winter.

15kW sounds like a lot though - ours is 6.2!

 

[MG4 Aussie owner]

Wow - you get 10 good months per year. We are lucky to get 5 on our East-West array in the UK!

In the first year we roughly broke even in March and October. Like you, building up credit for the Winter.

15kw sounds like a lot though - ours is 6.2!

I’m Australia we’re perfectly setup for renewable sources of energy. I get 4 cents a kilowatt•hour that I put into the grid. During late spring to early Autumn I get over a $1000 in credits very rarely using any energy from the grid.
We had a National government for ten years that did practically nothing in regards for solar or battery storage. One of the state governments runs at nearly 100% renewables during the summer and now has investors putting the biggest battery storage in the southern hemisphere.
Australia should be owning the renewable sector but the previous government was tied in so tightly with mining that our country completely missed the boat.
The other stupid thing is that we should have the same system as Norway for a national fund, but it’s all stuffed up. We have some of the largest reserves of natural gas yet we are selling it and at the moment and we’re (Australia) buying it back at a higher rate!