What problems can be caused by leaving the HV battery fully charged for several days?

[emmrecs]

I've seen a number of posts in this forum where users have strongly advised that it is not good for the battery to be charged to 100% and the car not be driven for some days after the charge is complete. Can anyone tell me what the effect is likely to be on the battery?

(Unfortunately, I first came across the advice after I had left my car fully-charged on two occasions, once for a period of about a week or so!)

I ask the question because my pre-facelift MG5 Exclusive LR has just had its first service at my MG dealer. I read elsewhere on the forum that it is not now standard practice for the service report to include the battery State of Health so I specifically asked for this to be done; the result was 98%!

I found this figure slightly concerning, after one year and less than 6,000 miles and wanted to seek advice, especially from those users who are clearly much more knowledgeable about electricity and electronics than I could ever be!

So, could that 2% loss be attributable, at least partially, to my "ignorance" about leaving the battery fully-charged?

TIA.

 

[dragon2611]

I too have a Rolec (smart) and use the ev.energy app.

If you are on a time of day tariff such as Go, then the 4 hour period will add approx 40-45% per night, so only charge when around 50% or lower. Alternatively set the ready by time to earlier than 04:30am and it should stop then.

And remember 100% is not 100%...there is a buffer managed by the BMS to prevent you charging to 100%

Is the Ev Energy app slow to react with the Rolec?

With the EO Mini Pro 2 the charger only checks in every 5 mins or so and even when you set the charger lock option to "Smart lock" it doesn't actually leave the charger on pause so what happens is when you plug in you end up charging for anything from a couple minutes to 5+ minutes before EV energy tells the charger to pause.

Sometimes it's long enough to use 1-2Kwh

 

[Gomev]

Is the Ev Energy app slow to react with the Rolec?

With the EO Mini Pro 2 the charger only checks in every 5 mins or so and even when you set the charger lock option to "Smart lock" it doesn't actually leave the charger on pause so what happens is when you plug in you end up charging for anything from a couple minutes to 5+ minutes before EV energy tells the charger to pause.

Sometimes it's long enough to use 1-2Kwh

My Rolec does absolutely zilch when I first plug in. The light remains blue (off) and dash in the car states not charging (Connected, uncharged). It does only poll it every 5 minutes so I don't get the 'Smart charge is planned' notification to my phone for several minutes.

 

[emmrecs]

My Rolec does absolutely zilch when I first plug in. The light remains blue (off) and dash in the car states not charging (Connected, uncharged). It does only poll it every 5 minutes so I don't get the 'Smart charge is planned' notification to my phone for several minutes.

Please ignore! "Correct" response in post 26! Apologies.

 

[kelloggs]

Just to try answering the initial question on why leaving the battery at 100% isn’t best practise.it’s mainly due to formation of solid electrolyte interfaces which can be accelerated at high states of charge. This “blocks” transference through the membrane to the electrode layer. It can also form dendritic material which can “tear” the membrane. End result is slightly more acceleration of capacity loss.. obviously there are other factors, lithium plating etc. just my clumsy attempt at clarification.

 

[dragon2611]

My Rolec does absolutely zilch when I first plug in. The light remains blue (off) and dash in the car states not charging (Connected, uncharged). It does only poll it every 5 minutes so I don't get the 'Smart charge is planned' notification to my phone for several minutes.

Must be the way the integration with the EO has been done.

 

[emmrecs]

My Rolec does absolutely zilch when I first plug in. The light remains blue (off) and dash in the car states not charging (Connected, uncharged). It does only poll it every 5 minutes so I don't get the 'Smart charge is planned' notification to my phone for several minutes.

Same for me, except the Rolec does almost immediately change (as soon as the car is locked and the plugs lock in) from Blue to Green.

 

[Gomev]

Same for me, except the Rolec does almost immediately change (as soon as the car is locked and the plugs lock in) from Blue to Green.

I'll check mine tonight when I plug in, I hadn't looked for that. My settings are that the charger is locked - smart lock.

 

[emmrecs]

My settings are that the charger is locked - smart lock.

Ditto, again.

 

[Gomev]

Same for me, except the Rolec does almost immediately change (as soon as the car is locked and the plugs lock in) from Blue to Green.

I'll check mine tonight when I plug in, I hadn't looked for that. My settings are that the charger is locked - smart lock.

Had a look last night and my light stayed blue after the car locked. Didn't wait so see if it went green after the app had polled it as was rushing between adverts on the tellybox.

 

[dragon2611]

Pretty sure mines going to spend a lot more time at 100% as switched to Agile due to my Go faster running out soon and most of the time at the moment the agile day rate being lower.

Ev energy doesn't have granular enough control to avoid it and still hit the cheaper windows.

 

[robertb]

There's currently no way for the charger to know the current SOC

Ohme do it by using the car manufactures API (I think EVenergy as well perhaps) but that only works for supported cars.

Since the pre facelift 5 doesn't have a limiter in the car's settings and there's no API to get the data form there's no way i can think of to easily terminate the charge at 80%

Something plugged into the OBD2 port can query the current SOC but I'm not yet sure if it's possible to do when the car is locked without setting the alarm off which seems to be the MG's behaviour if it detects an "intrusion" into the cars systems.

If there's no API for the pre facelift MG5, how does a Chargeplace Scotland Rapid know the SOC of my battery when it's plugged? Is it the case that there is one but MG will not give it to everyone?
The CPS rapids I've used all seem to know quite accurately, what my SOC is.

 

[Jomarkh]

If there's no API for the pre facelift MG5, how does a Chargeplace Scotland Rapid know the SOC of my battery when it's plugged? Is it the case that there is one but MG will not give it to everyone?
The CPS rapids I've used all seem to know quite accurately, what my SOC is.

All DC rapids can read the SOC as they don't work like AC type2.

 

[Lovemyev]

Had a look last night and my light stayed blue after the car locked. Didn't wait so see if it went green after the app had polled it as was rushing between adverts on the tellybox.

I have the early dumb Rolec unit and our ZS EV ( Gen 2 ) is set up to charge from the "off peak" tariff times that I have set into the head unit of the car.
Prior to plugging in the car, the status LED light on the front of the dumb Rolec wall box, is displaying the blue LED standby colour on the front panel.
I then unlock the car and plug in the type 2 tethered charging cable, then I re-lock the car with the fob, the cable then locks into the charging port.
The main contactor in the wall box then closes with a thump and the LED status light changes from over from blue, to the green LED ( which suggests it is charging ).
But, really here it is just carrying out the hand shake between the wall box and the car.
About 10 - 20 seconds later ( when the car has made the hand shake with the car ) it then realises that a "Delayed" ( Off Peak ) charge cycle has been set up.
Then the wall box will "Thump" again ( releasing the main contactor ) and the wall box will return to the standby status.
The LED on the front of the wall box, now will return to a blue standby status.
Shortly after this, the blue LED indicator lights in the charge port will completely extinguish.
The car is now in a "sleeping state" awaiting the "Off Peak" charge times to be activated.
I never charge the car on the much more expensive day time tariff of course.
Therefore the delayed charging function is always active.

 

[dragon2611]

If there's no API for the pre facelift MG5, how does a Chargeplace Scotland Rapid know the SOC of my battery when it's plugged? Is it the case that there is one but MG will not give it to everyone?
The CPS rapids I've used all seem to know quite accurately, what my SOC is.

Someone posted this the other day, was either here or one of the other EV related forums I was on.



Essentially for Rapid charging there's a load of communication as part of CCS that happens between the car and charging station,

Ac charging doesn't have this just a simple signal that can convey how much power is available from the EVSE.