First year battery capacity loss.

[wandle MG4 trophy]

The SOH on my Trophy is 100%. It’s 11 months old. 4k miles. Mainly home charging. Balanced monthly. This is after it recently sat at 6% for over a week and 100% for 3 days (long and boring story).

 

[Coulomb]

But remember that MG lies to you about your battery's SoH for the first year or so. They scale the SoH so that it's delivered at about 103% (wild guess), but any time that it comes to over 100%, they report 100%. Si in the first 12 months or so when the SoH is actually falling the fastest, it looks like it's actually completely stable. By the time that they report less than 100%, the rate of decrease in SoH has moderated, and you are more invested in the car. Personally I don't like this, I'd prefer to know the hard truth, but maybe they figure it's best for EV adoption and the planet to do it this way.

 

[securespark]

Arch, thank you for the explanation.

Is the "OK button press" the same in the 4?

 

[Archev]

Arch, thank you for the explanation.

Is the "OK button press" the same in the 4?

Never been near a 4 so I don’t know. But only the long range 4 would need that treatment. The SR short range has a different battery type.

 

[wandle MG4 trophy]

The battery is made up of many individual cells which need periodical adjustment to ensure they can each hold the same amount of charge. The only way that can be checked and adjusted is via the BMS (Battery Management System). This bit of the trickery works away automatically in the background but can only ensure every cell contains roughly the same charge when it can see them all full. So every month or two it needs to be connected to the AC power supply (eg granny or house charger) So that it can methodically check the contents. It takes time to go round and balance each cell as close as possible to all the others.
So just leave it to get up to 100% occasionally and allow a bit of time beyond that and it sorts itself out. When you set off to drive press the OK button on the right hand side of the steering wheel (mk1MG5) for a few seconds and the range mileage will adjust to give a more accurate guesstimate of what’s available.
Then jump in and go for a long drive with maximum range - OR as I do - go off for a coffee and cake somewhere to bring it back within the 20 - 80% range.
So charge slowly to 100% - coffee and cake - car at 80%.

I like to use this analogy for balancing a battery: if you fill an ice cube tray with a blast from the tap, some of the ice cube holes or ‘cells’ will be full or overflowing. And some will be partly empty. If however you fill the tray with a slowish trickle, the water will fill the first ‘cells’ and then overflow eventually filling every cell equally. Maybe not scientific but it works for my addled brain.

 

[Archev]

I like to use this analogy for balancing a battery: if you fill an ice cube tray with a blast from the tap, some of the ice cube holes or ‘cells’ will be full or overflowing. And some will be partly empty. If however you fill the tray with a slowish trickle, the water will fill the first ‘cells’ and then overflow eventually filling every cell equally. Maybe not scientific but it works for my addled brain.

All very well but it’s not the same without coffee ‘n cake

 

[Rolfe]

Never been near a 4 so I don’t know. But only the long range 4 would need that treatment. The SR short range has a different battery type.

Bear in mind that the OP's car is the SR with the LFP battery. I think he has been misled by reading the constant stream of advice meant for the LR NMC battery (and here we go again, I suppose).

The SR never needs to be stopped from charging below 100% as it is quite happy to be taken to 100% and stay there. It also likes to be balanced more often than the NMC battery - the recommendation is every week. So it's ideal if you just plug in and leave it to get to 100% and do its thing every time you charge. If you are stopping the charge before it reaches 100% for some reason then it will not be ideal. I think this is the root cause of the OP's problem.

 

[Rolfe]

Excellent I must watch his Skye holiday video again. Where Euan and his lovely wife Travel to and around the Isle of Skye in a very low range car. That’s what convinced me to go electric driving.

Do you have a link to that? It sounds lovely.

 

[Rolfe]

I like to use this analogy for balancing a battery: if you fill an ice cube tray with a blast from the tap, some of the ice cube holes or ‘cells’ will be full or overflowing. And some will be partly empty. If however you fill the tray with a slowish trickle, the water will fill the first ‘cells’ and then overflow eventually filling every cell equally. Maybe not scientific but it works for my addled brain.

That is a brilliant analogy. I am so stealing that.

 

[Tig170]

My SR now at 96.01% 14months old - 15k miles - however this is just with ABRP / car scanner - it was approx 97.2 % at 6k miles and 96.8% at 10k miles - so it is curving off in the right direction, however I've changed charging strategy during the (working week), which is essentially operates in the 65% - 35% range daily, and gently charge each night over 5 hrs to bring it back to 65% (I have an ohme-pro which does this automatically) - The only way I would really trust is how Cleevely EV calculate it - I think it uses Tesla tech?

at 5:30 in

 

[Archev]

Do you have a link to that? It sounds lovely.

I think it’s Plug Life Television no 13 from about 4 years ago.

 

[Archev]

Do you have a link to that? It sounds lovely.

Plug life TV from 4 years ago - episode 13. Happy viewing.

 

[CarbonEV]

It is recommended to balance the SR (LFP) battery each week.

What battery type is in the X-Power ?

 

[Rolfe]

I think it’s Plug Life Television no 13 from about 4 years ago.

Ta.

 

[Rolfe]

What battery type is in the X-Power ?

NMC. The only MG4 which has the LFP battery in Europe at least is the SE SR. However there is a Trophy trim with the SR battery available in some countries (Far East?).

 

[Rolfe]

My SR now at 96.01% 14months old - 15k miles - however this is just with ABRP / car scanner - it was approx 97.2 % at 6k miles and 96.8% at 10k miles - so it is curving off in the right direction, however I've changed charging strategy during the (working week), which is essentially operates in the 65% - 35% range daily, and gently charge each night over 5 hrs to bring it back to 65% (I have an ohme-pro which does this automatically) - The only way I would really trust is how Cleevely EV calculate it - I think it uses Tesla tech?

at 5:30 in

Aren't you taking it to 100% and letting it balance at all? If you aren't, that might be the reason why you seem to be losing some battery range.

 

[Tig170]

Aren't you taking it to 100% and letting it balance at all? If you aren't, that might be the reason why you seem to be losing some battery range.

Yes absolutely, I was just charging to 100% every 3-4 days (over 6 months), I couldn't see much difference in the voltage in cells internally, between max and min., but did see a bit of degradation each month. Then came across - BU-808: How to Prolong Lithium-based Batteries, and adapted my strategy. I also have 15kWh Pylontech batteries / VE Multiplus 5000 at home, which has more data, at home I've 99% SOH, after a year , and after the same time on the MG4 SE I've 96% SOH, very similar cells - CATL : but clearly outside temps, quality of the cells etc. is still of importance? - has anyone seen? (which i've decided to be gentle) - my car is owned, not on lease, which is why I'm trying to maximise battery life, without being daft about it.

 

[Rolfe]

OK, I see.

 

[Yorkiebarkid]

The SOH on my Trophy after one year (12k miles) is 100%, which I was very pleased with. I mainly charge at home.

 

[hharzel]

Did anyone get a test certificate when buying the car that the battery actually is 51kWh or 64kWh? I don't think using counterfeit battery cells is a non-issue when talking about anything that is made in China and as cars are mass produced in huge amounts and it is very easy to "cheat" just a little to make profit, something like EV batteries sound like an easy target for this.