Battery problem advice

[Gwynfor Hughes]

Last week inadvertently we fully drained the battery on our ZS Ev.
Charged it overnight on our Rolec charging unit.
Following day car wouldn't go into the ready mode and to cut a long story short vehicle towed into our local dealer.
3 days later its still there and the garage still attempting to resolve the battery issue.
We have now been informed that we should be charging the car at least once a month using the granny charger.
This is the first I have heard of this.
Can anyone advise please?

 

[Kithmo]

The granny or a 7kW charger, this is to balance the battery cells, it is in the manual page 292.

 

[Gwynfor Hughes]

So the advice I have been given is correct.
Use granny charger once a month for 24 hours?

 

[Kithmo]

So the advice I have been given is correct.
Use granny charger once a month for 24 hours?

I don't know if it takes 24 hours, but you leave it plugged in, granny or 7kW, until the MG badge goes off altogether. It pulses when charging and is lit steady when balancing then goes out when balanced.
As a matter of interest, did you mean you fully discharged the HV battery or the 12v ?

 

[Dave53]

So the advice I have been given is correct.
Use granny charger once a month for 24 hours?

If you don't have a 7kw home charger yes, the 7Kw home charger goes through a balancing process once charged usually about an hour or two after the main charge at least my Zappi 2 does

 

[Gwynfor Hughes]

Thanks for the replies.
Wife used the car and it showed around 24 miles for a 14 mile journey home.
Fell short around a mile from home.
I drove it back home with great difficulty.

 

[JodyS21]

It should/must be charged AND balanced using an AC charger once per month

 

[Gwynfor Hughes]

Thank you.
Just under a year of owning the car this is the first I've heard of this.
OK perhaps I should have read the manuel .

 

[JodyS21]

Thank you.
Just under a year of owning the car this is the first I've heard of this.
OK perhaps I should have read the manuel .

Oh dear, it'll be waaaaaay out of balance probably and need more than 1 AC charge and balance cycle.
The balance (following a full charge) only goes for a maximum of 10 hours per session.
Chances are if it's never been balanced for that amount of time it's likely it won't finish balancing in one session.

AC charge and balance (must be something like <90% charge to get it to do a balance once it's fully charged), don't unplug until the MG light has definitely completely gone out.
Use the car a bit and then repeat.
Ideally you want to check on how long it balances for once it's fully charged, if the balance goes on for longer than say 8 hours then I'd do another balance as it's probably not completed.

 

[Gwynfor Hughes]

Thanks for your reply.
I can't believe I was not aware of this process or made aware of the need to do this either by the dealer or home charger installer.

 

[Dave53]

.if your using a home charger

Thanks for your reply.
I can't believe I was not aware of this process or made aware of the need to do this either by the dealer or home charger installer.

 

[Dave53]

If you are using a home charger that is fine it should have been completing the balance, what you have to be wary of is that if you do a timed charge, say on octopus go or on Pv's then it could be missing the balance part of the charge that would mean doing a non timed charge at least once a month, I use Octopus go and Zappi 2, what I normally do is do the timed charge then do a short drive, come back plug it in and let it complete a full charge and balance, you don't need the Granny lead to balance if you use a home A/C charger, as said it will balance it for you if given the time to do it. Hope that makes sense.

 

[JodyS21]

I make sure that one of my weekly charge schedules, allows the charge to go on for something like 20 odd hours, so if it needs to it'll do the balance weekly.

I must say, if it wasn't for being on this forum from when I got the car, I wouldn't have known about the balance process. I did read some of the manual, but who really reads it all.....!

 

[Gwynfor Hughes]

Thank you for the response.
I have spoken to the company that fitted my Rolec charging station. Even he was unaware of this procedure.
He seemed to think that charging on domestic nature is no longer legal in Europe for safety reasons.
Yes I am on the Octopus Go Faster tariff and previously the Octopus Go tariff. So that may explain why the balance was not done.
I have only ever charged my vehicle at home on this domestic charger which he informs me is only 7kw? Sorry not technical in any way.
My fear is MG may use this to nullify my warranty on battery although mechanic in my local dealer assures me they won't.

 

[Gomev]

Just charge and balance, rinse and repeat as often as you can and the battery will recover.

 

[Michael Holt]

Just out of interest does anyone know if this balance is required for all ev's or just the ZS EV?

 

[Cocijo]

Yes - all HV battery packs require a balancing cycle now and then depending on the type. Most will complete this without the owner ever knowing about it.

 

[Michael Holt]

Yes - all HV battery packs require a balancing cycle now and then depending on the type. Most will complete this without the owner ever knowing about it.

Thank you Cocijo

 

[JodyS21]

Thank you for the response.
I have spoken to the company that fitted my Rolec charging station. Even he was unaware of this procedure.
He seemed to think that charging on domestic nature is no longer legal in Europe for safety reasons.
Yes I am on the Octopus Go Faster tariff and previously the Octopus Go tariff. So that may explain why the balance was not done.
I have only ever charged my vehicle at home on this domestic charger which he informs me is only 7kw? Sorry not technical in any way.
My fear is MG may use this to nullify my warranty on battery although mechanic in my local dealer assures me they won't.

I'm interested if you could elaborate on what the installer said about something not being legal in europe.

FYI, the car pops up a warning saying something along the lines of - This car needs charging/balancing on an AC charger, if it detects that it needs balancing.
However if you have the bad BMS software it fails to balance and the battery gets gradually worse and worse.

Perhaps I/we should have asked, what voltage does it show on the dash display after you've fully AC charged it. It should be either 450V or 455V dependant on software installed (+/- a couple of volts), if it's lower then you have the bad BMS software and have battery issues.

 

[Lovemyev]

Yes I am on the Octopus Go Faster tariff and previously the Octopus Go tariff. So that may explain why the balance was not done.
I have only ever charged my vehicle at home on this domestic charger which he informs me is only 7kw?

With regards to your energy supplier, I have a question ?.
Was you unplugging the car from the Rolec early, because the cheaper rate electricity had ended ?????.
Remember, when your Rolec is actually charging the HV battery, it is pulling a high load from your supply which CAN more costly on a standard day rate.
But when the car is performing the "Balancing Process" it is only pulling around 500 Watts.
Therefore the cost of carrying out this action is relatively low, even if you have to carry it out on the standard rate.
It would appear then that you have the higher powered 32Amp 7kw dumb Rolec unit.
Rolec do have an almost identical unit that is only rated at 3.5 kw's that will charge a lot slower of course.
These are fine for PHEV's of course, but for full BEV's - You need a 7 kw unit to be honest.
I have the very same unit.
Great advice from members above, next time you have performed a full charge & balance, check the voltage and predicted range on the pack and report back.
When the car was in for three days at the dealership, what did they do ????.
Did they upgrade ANY of the cars software ???.