Do not trust SOH. Interesting point. Kia discussion not MG.

[fshuk1]

 

[Rolfe]

Do your calibration charge and be happy. My range estimate in my MG4 is very good.

 

[fshuk1]

I think what he is saying is not to trust the estimate. The estimate = available battery size * mile/kwh
He was saying that miles/kwh experienced is accurate but the size it thinks is available might be wrong. So what we should do is actually drive a long distance with as low a remaining battery as possible and then do our calculation to see what is the size of the battery

 

[Gomev]

Fairly well known that Kia and Hyundai EVs, mine included, show 100% SOH for ages. It has always been taken that any degradation was calculated from within the buffer, so until that disappears it always shows 100%. So it still has max range/reported SOH, until the usable portion of the battery starts to disappear once the upper buffer has gone.
Who knows ? I think all most of us are only concerned about is how far will it go and does it go as far as it used to?

 

[siteguru]

I think all most of us are only concerned about it far will it go and does it go as far as it used to?

Absolutely this .. my SoH shows nearer 90% now, after nearly 3.5 years, but I've not noticed any obvious range loss.

 

[Bam Bam]

Does Bjorn think the issue is that the battery performance drops when it gets hot, and this happens much more in these degraded batteries? And they heat up when in use so a heat-tested figure would be more accurate than the cold figure the system uses?

 

[MickeySw]

Does Bjorn think the issue is that the battery performance drops when it gets hot, and this happens much more in these degraded batteries? And they heat up when in use so a heat-tested figure would be more accurate than the cold figure the system uses?

Don’t think so, NMC cells perform best around 30deg C, LFP even higher. MG does actively cool the cells while driving (MG5: 10deg or ambient, whichever is higher). This also explains the improved rapid charge rates in summer..

 

[MickeySw]

Fairly well known that Kia and Hyundai EVs, mine included, show 100% SOH for ages. It has always been taken that any degradation was calculated from within the buffer, so until that disappears it always shows 100%. So it still has max range/reported SOH, until the usable portion of the battery starts to disappear once the upper buffer has gone.

All EV manufacturers understate the true capacity of their batteries by a few %, to mask the initial, rapid degradation.

A SoH of 99% means the battery hasn’t lost just 1% of its capacity, more likely it degraded around 6%.

But as @siteguru stated, few will even notice the difference..

 

[Bam Bam]

Don’t think so, NMC cells perform best around 30deg C, LFP even higher. MG does actively cool the cells while driving (MG5: 10deg or ambient, whichever is higher). This also explains the improved rapid charge rates in summer..

Bjorn seems to think that degraded cells suffer from poor (higher?) internal resistance which heats them up more during use.

I'm assuming that a badly degraded cell/module heats up much more than 30 degrees under use.

Luckily our MG batteries (like all cars other than the early EVs) are much more actively cooled so hopefully will suffer from much less degradation.

Plus a bigger capacity pack goes through many fewer cycles to cover the same number of miles. Those early Leafs, Zoe's, ioniqs, e-golf's and Souls had to do twice the charging compared to a more modern longer range car.

 

[MickeySw]

Bjorn seems to think that degraded cells suffer from poor (higher?) internal resistance which heats them up more during use.

That's a fact, but as you mentioned this is a legacy issue and not common in modern EVs (although that may change when the current cars are considered 'vintage' in 10 years time..)

 

[Bam Bam]

That's a fact, but as you mentioned this is a legacy issue and not common in modern EVs (although that may change when the current cars are considered 'vintage' in 10 years time..)

Yeah hopefully less of an issue, but I suppose it will happen at some point once the batteries get very old. Hoping for 15 years but very high milage cars might have it earlier [edit - if NMC chemistry].

 

[securespark]

Do your calibration charge and be happy. My range estimate in my MG4 is very good.

You have the SE. What's your range estimate after a full 100% charge?

 

[Rolfe]

SR. Anything from 145 miles in the depths of winter if I've been running to Glasgow on the M8 to 230-odd miles if I've driven to Fort William in summer. And this hasn't changed in three years.

 

[securespark]

Sorry, when I said SE, I was thinking of our Honda...

You must be very light-footed!

 

[Gomev]

All EV manufacturers understate the true capacity of their batteries by a few %, to mask the initial, rapid degradation.

A SoH of 99% means the battery hasn’t lost just 1% of its capacity, more likely it degraded around 6%.

But as @siteguru stated, few will even notice the difference..

There appears to be different ways of calculating/reporting this degradation. Hyundai/Kia seem to be alone in their method whatever it is. How many MGs are reporting 100% SOH at e.g. 4 years old and 40,000 miles?