MG4 Battery Degredation

Tig170 said:

OBD Live data for the MG4

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Hello,

Where is the connector please ? Tnx.

EofT said:

Hello,

Where is the connector please ? Tnx.

Click to expand...

OBD port, under steering wheel, near left peddle rest.

All: I've found this post Degradation displayed in ABRP from a couple of years ago - it appears that on some models it cant read the battery degredation via the API, so it estimates it from when it charges - hence maybe why the MG4 is showing more degredation than originally expected

"For Tesla we don't have a way to directly retrieve the degradation or capacity so we calibrate while charging. The Tesla API reports how much energy is fed to you by the charger, so we track that against your battery percentage to determine the degradation. "

Tig170 said:

OBD port, under steering wheel, near left peddle rest.

Click to expand...

Thank you!

Bonjour à tous, permettez-moi de participer à cette conversation intéressante. Je suis moi-même en train de développer une application pour obtenir la mesure la plus précise de notre SOH.
Après avoir utilisé l'application ABRP, j'ai été surpris comme vous, j'ai une dégradation de 2.10 alors que je n'ai la voiture que depuis deux mois et 4000km.
Après une analyse approfondie, j'ai découvert le formulaire pour calculer le SOH, sur les valeurs du PID 22B061, la formule suivante doit être appliquée (A*256+B)/100.
256 est le nombre de charges et de décharges avant que la batterie ne commence à perdre de sa capacité. Nous obtenons donc exactement la même dégradation que ABRP donne sur son application.
Mais comme nous avons une nouvelle technologie de batterie qui doit faire plus de charge et de décharge, le nombre 256 est faux, je suppose que cela doit être plus.

Autre chose, que vous utilisiez la voiture ou non, il y a une dégradation de 0,01 % chaque jour depuis sa sortie d'usine.

Je suis aussi très inquiet de cette dégradation qui se poursuit chaque jour avec une baisse de 0,01 %. Je suppose que c'est une sorte de programmation. Quel que soit le nombre de kilomètres le type de recharge, nous subissons une dégradation de 0,01%/jour.

A moins qu'il y ait une mise à jour qui corrige ce problème, je ne sais pas.
Ma version de BMS est : IMCU401R01

Salutations

When new batterys degradate a lot, then the degradation settle down. This is one of two reasons many car makers have a hidden top buffer that become a bit less after a while, I know Bjørn Nyland (Tesla Bjørn) have measured this in Several cars and he think they do it to hide the initial battery degradering.

The other reason is to enable more regen with "full" battery pack and hide some EV spesifics from customers used to fossil cars.

The question is do MG have a top buffer? And does the cars degradation count include the buffer?
If so you wil get a greater degradation number.
Degradation should only be counted from 100% (usable) battery, top buffer is the part over 100%

The long range battery is 64kWh total capacity with 61.7kWh usable. So I assume the 2.3kWh difference is the top buffer. About 3.5% of the total.

And the SR battery (LFP) is 51kWh with 50.8kWh usable, so about 0.4% buffer.

Don’t forget that having a bottom buffer is also important.

During my last test on my 51kw LFP battery, I found out at 100% charge the BMS SOC showed 103.25% charge, I'm guessing maybe it's 03.25% buffer then?

king31 said:

After a thorough analysis, I discovered the form to calculate the SOH, on the values of PID 22B061, the following formula must be applied (A*256+B)/100.
256 is the number of charges and discharges before the battery begins to lose capacity. So we get exactly the same degradation that ABRP gives on its application.
But as we have a new battery tech that needs to do more charging and discharging the number 256 is wrong, I guess that needs to be more.

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The 256 in formula has nothing to do with charge cycles, it is just decoding two bytes (A & B) into a single decimal number - then dividing by 100 because all the values are sent as scaled integers.

Interestingly is it fair to say most of the replies here are from peeps with SR versions & not the LR battery pack owners .. My findings over the last 5 months with my Trophy - Constant GOM figures based on driving style - I DONT have any SOH info YET ..

mg4mc said:

The 256 in formula has nothing to do with charge cycles, it is just decoding two bytes (A & B) into a single decimal number - then dividing by 100 because all the values are sent as scaled integers.

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It has just been explained to me, thank you. This is the information that TchatGPT provided me