MG5 long range 71 plate SOH After 62000 miles. Do you have any figures?

[Tangoed Man]

State of Health. It can only be read with a ODBII reader.

Like all things with rechargeable batteries, EV high voltage batteries deteriate over time. The rate of this isn't linear and is also governed by treatment. Much the same as an ice vehicle, you rev the nuts off it when it's cold, it wears the internal components. Flooring it when the battery is cold will put undue strain on it, same goes for rapid charging at the big dc chargers, shoving 150kw/h into a battery isn't treating it nicely. Other things they don't like is being left at 100% charge for long periods of time or below 20% for long periods of time.

Ev batteries usually have an overhead (unusable) part to the battery so often the first % or so of health isn't really noticed.

The MGs battery warranty is around 70% from memory, I don't think I've seen any anywhere near that quoted on here, in fact most are high 90's

Mine is going in for its 2 year 30k service next month and I'll be interested to see the result. I charge pretty much daily to 100% on a rapid charge. At a guess it's 99% as I'll see 249 on the range meter at 100% sometimes.

Rapid DC charging does not damage the battery

 

[MickeySw]

Rapid DC charging does not damage the battery

Correct, but it seems to accelerate the degradation process a bit..

 

[ayres]

3rd service this morning. 46000miles. 2.5 years. 93%. Rarely fast charge. Mostly charge to below 80%. Driven pretty easily mainly commute to and from work. Pretty disapointed with that much degradation.

 

[5teep]

That doesn't sound right ayres, I'd get it checked again. Has your range dropped noticeably?

Reading your post again, it might be a balancing issue, charge to 100% on AC at least once a week, this will keep your battery balanced.

 

[MickeySw]

That doesn't sound right ayres, I'd get it checked again. Has your range dropped noticeably?

Reading your post again, it might be a balancing issue, charge to 100% on AC at least once a week, this will keep your battery balanced.

Balancing does not affect SoH (unless it’s miles out), see post #20 on how to recalculate battery capacity.

 

[ayres]

Just finished a drive to notts. Car seems to confirm the loss of range here. Very disappointing.

 

[MickeySw]

Just finished a drive to notts. Car seems to confirm the loss of range here. Very disappointing.
View attachment 27184

Did you ever do the recommend SoC < 10% to 100% on AC in one go, followed by balancing?

Might also be worth to do a hard reset beforehand (disconnect 12V aux)

Lets us know afterwards.

 

[Gomev]

3rd service this morning. 46000miles. 2.5 years. 93%. Rarely fast charge. Mostly charge to below 80%. Driven pretty easily mainly commute to and from work. Pretty disapointed with that much degradation.

Simple test to check SOH.
Do a full charge to 100% and balance, i.e. leave it on charge for a while while at 100%. (as recommended by others above).
Turn car on to Ready state.
Reset the accumulated trip.
Leave in Normal mode.
Look at range on GOM.

If SOH is 100% it will show the WLTP figure for your car. If SOH is 99% it will show 99% of WLTP for your car etc. etc..

Also I think you meant to say you almost always fast charge, rarely Rapid charge.

 

[ayres]

Before any trip (usually once a month on average car will get a balance charge. I have done 1 last night so will see results when I go out to car.
I mean 7kW charge on home charger. Car has had less than 10 rapid charges in its life.

Suggests more than 93%to me. Car charged to 100% and left on after for a good while. Trip computer reset. And shows 221.

 

[Pebblefeline]

The gom is essentially useless

Mine shows over 270 + miles at 100 percent as recently I have been driving around town

My battery soh is about 99.2 ish after 10000 miles.

Do bear in mind that these batteries do their degradation quickly at the start and then slow dramatically for the rest of their life as far as I understand it.

You trip to Notts looks ok. I am guessing some mixed driving and you have a rough total range of about 220. This is about right for an mg5 lr.

Mine would be pretty similar

 

[ayres]

It is deff less than I would expect or managed before. Previous service was 30000 and 98%battery. In 16000 it’s dropped the next 5+%.
Expected some degradation but not more than cars on twice its mileage.
The high miles per kw is due to very conservative driving and lots of average speed limits.

 

[Verdigris]

I checked my SOH today and it gave 96.45% (24k miles), which was a bit disappointing. However, as I'll be being paid to use electricity, again, tomorrow, I shall take it to 100% SOC for a balance charge, and see what it says then.

 

[kevin ellard]

The gom is essentially useless

Mine shows over 270 + miles at 100 percent as recently I have been driving around town

My battery soh is about 99.2 ish after 10000 miles.

Do bear in mind that these batteries do their degradation quickly at the start and then slow dramatically for the rest of their life as far as I understand it.

You trip to Notts looks ok. I am guessing some mixed driving and you have a rough total range of about 220. This is about right for an mg5 lr.

Mine would be pretty similar

Its not really useless, it just doesn't predict the future.

 

[Pebblefeline]

Fair comment

I retract the useless thing

 

[Gomev]

It is deff less than I would expect or managed before. Previous service was 30000 and 98%battery. In 16000 it’s dropped the next 5+%.
Expected some degradation but not more than cars on twice its mileage.
The high miles per kw is due to very conservative driving and lots of average speed limits.

That does seem low. I would get an OBD on it and check the cell voltage levels after it has balanced. They should all be virtually the same across all the packs and within the packs. i.e. the high/low on each should be the same, or very very close, if perfectly balanced.
The 'battery' can only use up to the level of the lowest cell, so if there is a bad 'un that will affect the whole thing.

 

[ayres]

Thinking about dropping cleverly a message see what they advise. Can anything be done about a bad cell?

 

[Gomev]

Thinking about dropping cleverly a message see what they advise. Can anything be done about a bad cell?

In theory yes. I presume everything else was turned off, such as heater/aircon etc. when you took the photo.

 

[ayres]

In theory yes. I presume everything else was turned off, such as heater/aircon etc. when you took the photo.

Yes everything else turned off.

 

[Pebblefeline]

Did you do a full reset?
Pull the battery negative for a minute to clear all the previous learning from the ecu then try again and see if the number has gone up.

At historical 4mi/kWh I get a total range of about 240.
If the car thinks the accumulated average is 3.5 then this figure drops towards 200.

If you have done a full clear then ignore this post. I hope you find a solution.

 

[ayres]

I am away so I haven't done a full reset (Battery pull). Accumulated mileage before reset was 3.9miles per kWh. Which with that in mind should be 234 not 220 miles.