Battery problem advice

[Bazzer44]

Sorry should have said your guess is spot on

 

[chowbenter]

If you have a home energy meter in your home, you can save on a bit of leg work.
When the car first commences the balancing process, it will be pulling around 500 Watts, then when it is close to completing, it will then reduce down to 300 Watts and then finally down to 175 Watts just before actually completing.
Yeah - It is sad that I have noticed this happening !.
I did have some issues on my car when it returned home from the BMS update and it’s first service.
It’s charging habits became weird to say the least upon its return.
Therefore I was documenting it’s charging behaviour via my home energy meter.

I never thought of looking at the energy meter to check on the balancing, I'll give it a try next time.

 

[Lovemyev]

I never thought of looking at the energy meter to check on the balancing, I'll give it a try next time.

Yeah - Handy for keeping a quick eye on what is going on !.
My wall box is in the garage, so using the energy meter saves the in and out all of the time !.
From a low (ish) SOC you should be seeing something like 7.4 kw’s being pulled on your meter, depending what other items are pulling energy of course.
When the car hits around 97% it will reduce the demand down to 3.5 kw’s.
Then at 100% SOC the car will commence the balance process.
The meter will drop to around 500 Watts firstly, then down to 300 and finally down to 175 (ish) Watts before finishing shortly after.
Mine looks like this when the car is on charge.

 

[chowbenter]

Yeah - Handy for keeping a quick eye on what is going on !.
My wall box is in the garage, so using the energy meter saves the in and out all of the time !.
From a low (ish) SOC you should be seeing something like 7.4 kw’s being pulled on your meter, depending what other items are pulling energy of course.
When the car hits around 97% it will reduce the demand down to 3.5 kw’s.
Then at 100% SOC the car will commence the balance process.
The meter will drop to around 500 Watts firstly, then down to 300 and finally down to 175 (ish) Watts before finishing shortly after.

Sounds a lot better than going to the garage to check, there are no windows in my garage so I don't switch the lights on so I see the reflection of the pulsating/lit MG badge on the steel door.

 

[Kayged]

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

You can also use a 7kw charger but leave it connected until it tells you it is complete. You should get a message if you need to balance the battery.

 

[Tim Falkiner]

I read someone likening the battery pack to an ice cube tray and rapid charging like filling an ice cube tray with a fire hose. Occasionally you need to fill the tray with a slow-running sink tap.

 

[Gomev]

You can also use a 7kw charger but leave it connected until it tells you it is complete. You should get a message if you need to balance the battery.

If you wait for the warning, you've probably waited longer than necessary.

 

[Gwynfor Hughes]

An update on my current situatio

 

[Cocijo]

They are balancing the battery pack by the sound of it. It will be fine when you get it back. Others on here are doing their own balancing to get the pack back to normal. If you can get a comparable EV to use (which you should), then just relax and don’t stress. worse things happen - it will work out fine in the end.

 

[Gwynfor Hughes]

They are balancing the battery pack by the sound of it. It will be fine when you get it back. Others on here are doing their own balancing to get the pack back to normal. If you can get a comparable EV to use (which you should), then just relax and don’t stress. worse things happen - it will work out fine in the end.

Thanks that is reassuring.
I don't mind one bit as long as the car is fine thereafter.

 

[Phil Hayward]

I missed the dodgy BMS, I have fully charged twice since the latest BMS update, voltage was 449, range 216 and 206, eco no heater. Accumulated total reads 4.5 mpkw. I am missing a volt, I think the update should let it charge to 450, near enough.
The important reading is the voltage on the lowest cell.
Something weird about Lipo charging, the balance charger I use for tool batteries never leaves the cells at 4.2v, balance function goes on for two hours and gets it within 0.05 v, run it again and after another 2 hours it gets a bit closer.
I hope it comes back to you with a balanced battery

 

[Gwynfor Hughes]

Just an update.
I had my car back on 31st August after the battery had been balanced.
A very slow process.
I have been informed by the mechanic that a warning signal will now show on dashboard at some time in future instructing to slow charge.
When this happens it seems I should run the battery to as low as possible and then use the granny charger for maybe up to 15 hours.
I have been told that no further action is required.

 

[Lovemyev]

Just an update.
I had my car back on 31st August after the battery had been balanced.
A very slow process.
I have been informed by the mechanic that a warning signal will now show on dashboard at some time in future instructing to slow charge.
When this happens it seems I should run the battery to as low as possible and then use the granny charger for maybe up to 15 hours.
I have been told that no further action is required.

All good advice, but if you are NOT a regular rapid charger, I would not be overly concerned.
Regular rapid charging can invoke the “Carry out a slow charge” warning.
Have they given you any further instruction on charge / balancing going forward ?.

 

[Gwynfor Hughes]

Thanks for your response.
I have never used a rapid charger as I use a home charging device as to date all my journeys are relatively local.

 

[Kithmo]

Thanks for your response.
I have never used a rapid charger as I use a home charging device as to date all my journeys are relatively local.

In the handbook, MG recommends a full charge and balance once a month (7kW or granny).

 

[Cocijo]

Hopefully you can now enjoy your car hassle free

 

[Gwynfor Hughes]

Its great having my MG back and really appreciate it after driving a petrol hired car.

 

[nmhampson]

I did read some of the manual, but who really reads it all.....!

I have owned cars previously with two manuals; one a small "stuff you really need to know" quick guide which is quick and simple to read guide and a weightier tome with everything from how to get into your car to how to remove the spiggot-farrow from a worn umber-slinger.

Always surprised more don't do this, a quick start guide would be so handy.

 

[BarryH]

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?

This advice is way out of order. There is no requirement to use the so-called Granny Charger at all. It is however stated in the manual (the table is on page 157) that in "the event of the high voltage battery low warning" "Slow charging" EITHER on "Residential Electricity" ie a level 1 Granny Charger or "AC charging station" ie a level 2 public or home 7 kW AC charger such as your Rolec, to "Equalize" the High Voltage Battery. This is also called a "Balance charge".

The manual also states on page 292-293 in the Maintenance section paragraph 3, that it is "recommended" "where possible" to carry out a "9-hour slow charge every month to extend the service life of the high voltage battery". This is a maintenance Balance charge which allows the Battery Management System or BMS to balance the voltages across the cells in the pack (108 cells in the ZS). In reality this can take upwards of thirty minutes (30 minutes) after Fully Charge State of Charge (100% SOC) has been reached. [There is a maximum voltage difference that can be Balance in any on session and I believe the maximum time in one session the BMS will do the Balance charge is 6 hours but @MilesperkWh can correct me on that]. During this "Balance charging," the charge rate drops the charging rate from 7 kW to trickle of about 300 watts (as I have described in other threads) and this allows the cells with lower voltage to continue to be trickle charged to "Balance up" or "Equalise" cell voltages in the pack. There is also a degree of balancing when driving from 100% SOC down to about 97% SOC. Balancing when charging though Only happens on AC charging ie on your Type 2 Cable and NOT on CCS DC Rapid chargers. A "Granny Charger" is also an AC charger.

My practice is to use a timed 4-hour charge (5p Octopus Go) when needed and every 2 to 3 weeks have an extended 6 hour timed charge and my energy monitor shows that even with a 6-hour window the car has finished any balancing charge well within 5½ hours and draws no more current.

If you're yet to get 5p / kWh charging and to share £100 with me (50:50) go to: share.octopus.energy/zappy-guppy-175

 

[Dr Dave]

Just an update.

When this happens it seems I should run the battery to as low as possible and then use the granny charger for maybe up to 15 hours.
I have been told that no further action is required.

This advice is misleading. No need to use granny charger balancing using a 7kw is fine. You also do not need to run the battery as low as possible as long as you have one segment below full battery you can balance.
You have been given bad advice my the mechanic.