Loss of range and warning light 'please slow charge high voltage battery' coming on 4-5 times per day

[JillianW]

Great info on this thread. I was getting the annoying "slow charge" message and red battery sign to. I also noted I was struggling to get even 85 miles on a full charge in E mode and I was get 4+miles p/Kw some times too. I don't use the heating/Fans but only in extreme situations.
This range was also during the mild weather in spring (before the constant rain!). I only have a granny charger and i've always charged on this but i've just checked my cars volts now and it reads 402V!!!!!!!! and the slow charge message popped up again and i only have 64 mile range!

I've just come back from the MG dealer today as they recalled it for the new BMS update and they said it will take 350 HOURS (yes 350 hours ) of charging to stabilize the batteries. The dealership said driving the car also counts as the re-gen brake also counts but not seen it mentioned on hear regarding the regen counting.
Sounds like this is going to take a long time to get sorted.
I also noted the dealers NEVER offered to balance the batteries for me the as per the MG paperwork in the posts above. The service staff who I found difficult through the whole process just told me to use the battery up and just keep charging it as normal and it will improve.

I feel relieved someone else is having the same problem as me. Very difficult attitude at my dealers service Centre- am off again tomorrow with all the info about rebalancing the battery and a record of my battery useage vs kms travelled to show I have lost range . My battery voltage has improved slightly with the charging at home from 425v to 431v but “please slow charge high voltage battery” warning light still coming on several times a day- service Centre just say keep watching the warning light?????

 

[Jamlam]

"Keep watching the warning light?" What do they mean?
Also I still keep getting the slow charge message when I am fully charged, 60%, 45%, 30% charged, basically at any state of the battery. I thought this message was just supposed to appear when my car was supposedly 100% charged but it's actually got more space to add energy/power to the battery so it only shows when fully charged. I have had the 2nd bms update btw.

 

[JillianW]

"Keep watching the warning light?" What do they mean?
Also I still keep getting the slow charge message when I am fully charged, 60%, 45%, 30% charged, basically at any state of the battery. I thought this message was just supposed to appear when my car was supposedly 100% charged but it's actually got more space to add energy/power to the battery so it only shows when fully charged. I have had the 2nd bms update btw.

Stay tuned ? will see what they tell me tomorrow for my 3rd service visit for warning light and low range?

 

[JillianW]

Stay tuned ? will see what they tell me tomorrow for my 3rd service visit for warning light and low range?

 

[JillianW]

I have posted above the next stage of getting my battery range back to normal after BMS upgrade .I need to drive 100km after full charge on DC charger and the fully charge on AC charger and drive another 100kms. Hoping this will fix my car?

 

[Cocijo]

I have posted above the next stage of getting my battery range back to normal after BMS upgrade .I need to drive 100km after full charge on DC charger and the fully charge on AC charger and drive another 100kms. Hoping this will fix my car?

Interesting. My understanding is that cell balancing only occurs on AC charging. I’m not sure what the reference to DC actually means.

 

[Lovemyev]

I am of the same opinion?????.

 

[JillianW]

Interesting. My understanding is that cell balancing only occurs on AC charging. I’m not sure what the reference to DC actually means.

I asked that question and they told me rapid chargers are DC chargers and I had to run almost to empty and charge on rapid charger (DC) and then drive 100km to assist the battery balance - going to try and see what happens - today my battery voltage was only 418v on the way home from service ?

 

[Jamlam]

My understanding that it was the use of up to 7kw chargers that help the batteries balance not fast/rapid chargers. This will delay the balance process. Who is the dealership?

 

[JillianW]

Brighton MG in Melbourne Australia - still trying to understand it all - I have read you shouldn’t always fast charge so not sure how this is going to help but will try it ?

 

[Gomev]

My understanding that it was the use of up to 7kw chargers that help the batteries balance not fast/rapid chargers. This will delay the balance process. Who is the dealership?

Brighton MG in Melbourne Australia - still trying to understand it all - I have read you shouldn’t always fast charge so not sure how this is going to help but will try it ?

Seems to be some confusion over terms here.

7kW is a fast charge, the granny is a slow charge, both of which will charge then balance when battery is 100%.
DC charging is rapid (although not always as rapid as we would like ) and as far as I am aware does not balance after a full charge and is more liable to make the cell imbalance worse.
We have also been informed you only need to run the battery down to about 93% before 7kW charging to full and balancing again.

 

[Jamlam]

To clarify I mean the same as Gomev ???

 

[Cocijo]

Brighton MG in Melbourne Australia - still trying to understand it all - I have read you shouldn’t always fast charge so not sure how this is going to help but will try it ?

Be careful using DC rapids - my understanding is it can make the battery imbalance worse. Your pack voltage is very low. I’ve heard that MG supply a car while the dealer sorts out the imbalance on severe cases. Might be worth a go and see what they say. It will take a long time to get back up to c450v And using DC rapids will make it worse in my opinion.

 

[JillianW]

Seems to be some confusion over terms here.

7kW is a fast charge, the granny is a slow charge, both of which will charge then balance when battery is 100%.
DC charging is rapid (although not always as rapid as we would like ) and as far as I am aware does not balance after a full charge and is more liable to make the cell imbalance worse.
We have also been informed you only need to run the battery down to about 93% before 7kW charging to full and balancing again.

Seems to be some confusion over terms here.

7kW is a fast charge, the granny is a slow charge, both of which will charge then balance when battery is 100%.
DC charging is rapid (although not always as rapid as we would like ) and as far as I am aware does not balance after a full charge and is more liable to make the cell imbalance worse.
We have also been informed you only need to run the battery down to about 93% before 7kW charging to full and balancing again.

Hi - the docs I posted from the dealership via MG Australia are detailing the balancing process - I wonder if it is the combined action of charging with both the AC charger , which would be the granny charger (7kw) at home then driving the 100kms and then 100km after rapid (dC) charge is the balancing process - the docs talk about a new software update that helps the car re balance with this process- I can’t test the theory yet as we are in lockdown again and can only travel 5Km from home - ?

 

[Coulomb]

which would be the granny charger (7kw)

The granny charger (the EVSE supplied with the car, with a 3-pin plug) is 2kW in Australia, a little more (2.4kW) in the UK.

The term "fast charger" used to mean up to 50kW DC charging, at least in Australia. I've noticed that at least on this forum, it now seems to mean high power AC charging, 7-22kW via the on board charger. Now all DC chargers seem to be called "rapid" chargers, and the higher power chargers (at or above about 150kW, though that may change) are "ultra rapids".

Technology seems to be progressing faster than language can keep up.

 

[JillianW]

The granny charger (the EVSE supplied with the car, with a 3-pin plug) is 2kW in Australia, a little more (2.4kW) in the UK.

The term "fast charger" used to mean up to 50kW DC charging, at least in Australia. I've noticed that at least on this forum, it now seems to mean high power AC charging, 7-22kW via the on board charger. Now all DC chargers seem to be called "rapid" chargers, and the higher power chargers (at or above about 150kW, though that may change) are "ultra rapids".

Technology seems to be progressing faster than language can keep up.

I was given a 3.1kw /13amp charger with the car for home charging - assume that’s a granny charger? Agree the technology is changing more quickly than the terminology and the service centers seem to be slower to understand the technology than anyone so not much good help out there?

 

[Coulomb]

I was given a 3.1kw /13amp charger with the car for home charging - assume that’s a granny charger?

Wow, that's a step above what usually comes with MG EVs in Australia. Perhaps call it a granny charger plus.

 

[Gomev]

Wow, that's a step above what usually comes with MG EVs in Australia. Perhaps call it a granny charger plus.

SuperGran

 

[Dave S]

Thankyou! Am starting the long journey of trying to explain all this to my dealer /service dept?
I am slowly getting higher voltage readings the more equalization charges I do but it’s only at 431v - still along way to go ..

@Jamlam

Welcome to my world. I was down to 427 volts and had about 85 miles range (winter driving!).

Dealer ran correcting update, and then I have built up the residual voltage after a full charge back up to 449v. Now that it's fully repaired, I'm as happy as a Larry!

It takes a while mind you. Any queries, just holler as I know your pain!

 

[JillianW]

@Jamlam

Welcome to my world. I was down to 427 volts and had about 85 miles range (winter driving!).

Dealer ran correcting update, and then I have built up the residual voltage after a full charge back up to 449v. Now that it's fully repaired, I'm as happy as a Larry!

It takes a while mind you. Any queries, just holler as I know your pain!

Thanks!?