Evening all,
I have recently noticed over the last few weeks that upon full charge and battery equalisation the GOM, which used to read 163miles, now consistently reads 157miles. All latest updates are on. No dodgy BMS. Weather this week has been pleasant. Battery voltage reads 449v and current / accumulated journey have been reset.
It’s the exclusive model, is a 70 reg plate (so 17 months old) and has 7500 miles.
Am I missing something or have I experienced battery degradation? ?
Thoughts greatly appreciated.
Are you resetting BOTH of the trip recorders before you do your readings ?.
If not, you need to !.
Are you carrying out a balance cycle about once a month ?.
I will share my story with you and you can come to your own conclusions on this subject, after reading about our car.
Our previous Gen 1 ZS EV was just over two years old and covered just under 20,000 miles before we exchanged it for the new face lift LR Trophy.
The car had only charged once on a rapid, the rest of the time it charged from home on our A/C 7.0 kW wall box.
The car was probably one of the first privately owned cars to receive the BMS update released on the 15th Jan 2021.
The update was applied on the 18th Jan 2021.
When first done, the car would display a range of between 162 - 163 miles on the GOM after a fully charge and balance.
This was the base line figure used by MG when applying the software update.
Our pack voltage ( with everything tuned off ) was 449 - 450 volts at the time.
Over the next few months, I started to notice that the predicted range on the GOM had slowly started reducing it's prediction of achievable range.
Slowly slipping back to 160 then slowly bit by bit towards the upper 150's.
Over about the next 12 months, the predicted range continued slowly slipping back to 154 miles. Just before we sold it, it dropped back to 153 miles of range after a full charge and balance.
This was with BOTH trips reset and NO electrical systems running at the time of checking.
The pack voltage was still at 449 volts though !.
When the BMS is applied, it completely wipes the slate clean and therefore I believe, it is relearning everything about the true condition of the pack all over again.
The historical data has been wiped when the update was carried out.
I think it commences learning from the 163 mile starting point.
If you car had the update done and it had not covered many miles, then the learning process is much quicker.
If your car had been badly affected by the "Buggy" software, then it would take a while to recover the cell imbalance and hit the magic 445 volts / 163 miles of predicted range.
Our car ( like yours ) was NOT affected by the "Buggy" software.
I takes time for the system to evaluate the condition of HV pack and then come back, with what it feels is a more accurate SOH of your pack.
If you have a OBD dongle, you can get the battery SOH via the software App.
I did not have such a dongle, but you can make a pretty good guess of your SOH really.
If the known good base line target is 163 ( 449 - 450 volts ) post BMS and like in our case, your predicted range was 153 - then 10 miles has gone missing somewhere ?.
10% of 163 = 16 miles and we have roughly 10 miles missing.
Rough guess is then, that our packs was sitting at around 93 - 94% ( ish ) SOH ???.
The reduction in range appeared slowly progressive, maybe at some point it would level out ?.
But my personal feeling was that some battery degradation HAD taken place in that two years and almost 20,000 miles.
I could be totally wrong here of course, but my gut instincts tell me different !.
