Low voltage battery discharging

[Nickel]

Car is a ZS Trophy LR, just under a year old.

We have started seeing messages that the "Low voltage battery needs charging, do not leave car more than 3 days unused." Or words to that effect.

Yesterday evening we parked up with the battery registering 13.8V. Later in the evening it was down to 13.0V, measured via the MG Smart app.

Now (lunchtime), it's down to 12.2V.

As far as we can tell, nothing we control is on. And the car hasn't been used since we parked.

Can anyone shed any light?

Nick

 

[scoobeesnac]

I can highly recommend a 12v battery monitor for peace of mind. Attaching a 'normal' day. In our last ZS EV MK2 hire we noticed the battery was not doing so well, but touch wood our current car is doing ok.

The only issue I noticed was with a Zappi v1 where the 12v seemed to have been draining when connected but not charging - the car warned me to start the car to charge the 12v.

 

[boira]

I had to leave my car for 7 days as I was on holiday. Came back and the car started fine. Have left parked over this weekend and the app shows 12.8v. I am sure with normal use next week it will return to over 13v displayed in the app.

Interestingly the app reset while away and I couldn't reconnect until I returned. It is also worth checking if you have something slow draining the battery. I have a bluetooth android auto that does take a small amount of power. I would disconnect that if leaving the car idle for longer than a week in the future.

Hopefully your battery will be sorted.

Is this Bluetooth device the ones which allows you to use the Android Auto/Carplay wireless (and is plugged to the USB-A port)?

I am planning of getting one of that in the future, but was just worried about the energy consumption on stand-by...

 

[Gadget Geek]

The usb A and C ports only have power when you wake up the car.

 

[boira]

The usb A and C ports only have power when you wake up the car.

That's good to know, thanks!

 

[Lovemyev]

Any good ????.

 

[evcog]

Is this Bluetooth device the ones which allows you to use the Android Auto/Carplay wireless (and is plugged to the USB-A port)?

I am planning of getting one of that in the future, but was just worried about the energy consumption on stand-by...

Yes it makes it so much easier to bluetooth connect for android auto rather keep plugging in and out the phone. I for one don't like leaving my phone in the car when I stop for a loo break or coffee. I'm also a type 1 diabetic and use a libre reader on my phone to monitor blood sugar so like to keep the phone with me.

I think any drain would be very small but I have noticed the green led is on before I start the car. Perhaps it turns off when you lock the car I don't know.

 

[scoobeesnac]

Any good ????.

That's the one.

 

[Gadget Geek]

Yes it makes it so much easier to bluetooth connect for android auto rather keep plugging in and out the phone. I for one don't like leaving my phone in the car when I stop for a loo break or coffee. I'm also a type 1 diabetic and use a libre reader on my phone to monitor blood sugar so like to keep the phone with me.

I think any drain would be very small but I have noticed the green led is on before I start the car. Perhaps it turns off when you lock the car I don't know.

The car wakes up when you unlock it, and shuts down when you lock it. Try plugging a usb light or fan in and watch what happens.

 

[Nickel]

Thanks everyone for all the effort and info. It does seem my LV battery is discharging quickly.

I took it to the dealer today, to no avail. They checked the battery voltage, which was 12.6V at the time, took it for a drive round the block and said the charging voltage was fine, so all was OK. Even informed me that I don't actually use the 12V battery.... I was tempted to splutter theatrically and ask why MG bothered fitting it then, but I let it pass...

The core message was that he didn't think the battery was in a state where MG would consider replacement. I'll just have to log what's happening and keep fingers crossed. Thankfully we have no plans to leave it in an airport car park for a couple of weeks at the moment. And a jumper pack will find its way onboard when we do go away.

I shall keep my fingers crossed that we have @GameZone's good fortune!

The usb A and C ports only have power when you wake up the car.

Do you know if that also applies to the USB A behind the rear view mirror?

I'm assuming it does, but have had a dashcam plugged into it for the last few months. The dashcam apparently switches off when the car powers down, but I vaguely wondered if that might be what was causing my problem.

 

[GameZone]

Thanks everyone for all the effort and info. It does seem my LV battery is discharging quickly.

I took it to the dealer today, to no avail. They checked the battery voltage, which was 12.6V at the time, took it for a drive round the block and said the charging voltage was fine, so all was OK. Even informed me that I don't actually use the 12V battery.... I was tempted to splutter theatrically and ask why MG bothered fitting it then, but I let it pass...

The core message was that he didn't think the battery was in a state where MG would consider replacement. I'll just have to log what's happening and keep fingers crossed. Thankfully we have no plans to leave it in an airport car park for a couple of weeks at the moment. And a jumper pack will find its way onboard when we do go away.

I shall keep my fingers crossed that we have @GameZone's good fortune!

Doesn't use the battery? Try using the app when the low battery messages show up, or try unlocking your car when it's flat. Anyway, same story here. They checked the battery, and apparently it was fine.

 

[Lovemyev]

They checked the battery voltage, which was 12.6V at the time, took it for a drive round the block and said the charging voltage was fine, so all was OK. Even informed me that I don't actually use the 12V battery....

This type of response ( unfortunately ) does not surprise me I am very sorry to say TBH.
I am struggling to understand WHY he thought taking it for a spin around the block, was even required or what it was going to achieve / prove ?.
Did he / she think they where diving a fossil by any chance .
The car should be charging the 12 volt battery as soon as READY mode is selected.
Not in STANDBY mode ( foot off the brake ) of course.
I do agree that MG would likely refuse a claim for a new battery based on the results of the test they conducted ( assuming they did it correctly that is ).
Other owners have reported similar concerns and have been sent packing.
This has resulted in either no more complaints, or getting recovered at a later date by MG / AA assistance, or funding the replacement of a new battery themselves.
I made the call WAY back in 2019 to always carry a jumper pack under the drivers seat.
Strangely enough after over 40 years of driving fossil cars and never though of carrying one, this changed when we bought our first full BEV.
It has been used a number of times to help out either family members or a couple of stranded drivers.
All of the cars it has jumped, have all been fossil burning cars and no EV's to date.
A jumper pack is the best "back up plan" worth investing into ( next to a space wheel IMHO.)

 

[Gadget Geek]

Do you know if that also applies to the USB A behind the rear view mirror?

Yes.

Thanks everyone for all the effort and info. It does seem my LV battery is discharging quickly.

I took it to the dealer today, to no avail. They checked the battery voltage, which was 12.6V at the time, took it for a drive round the block and said the charging voltage was fine, so all was OK. Even informed me that I don't actually use the 12V battery.... I was tempted to splutter theatrically and ask why MG bothered fitting it then, but I let it pass...

The core message was that he didn't think the battery was in a state where MG would consider replacement. I'll just have to log what's happening and keep fingers crossed. Thankfully we have no plans to leave it in an airport car park for a couple of weeks at the moment. And a jumper pack will find its way onboard when we do go away.

I shall keep my fingers crossed that we have @GameZone's good fortune!

Did they test it under load, or just put a voltmeter on the terminals? 12.6V after driving it to the dealership sounds low to me. I'd have expect over 13V.

 

[Nickel]

Did they test it under load, or just put a voltmeter on the terminals? 12.6V after driving it to the dealership sounds low to me. I'd have expect over 13V.

I don't know. I know he didn't do a "drop test", which he mentioned, but which I don't know much about. I think he said 12.6V, but to be honest he gabbled it all out with the message all is well, and seemed a bit surprised when I questioned that.

How would you suggest I kept an eye on it to make a better argument next time?

 

[Lovemyev]

There a couple of options.
A basic check can be conducted with a multi meter.
You could install a 12 volt battery monitor ( See the video in #27 in this thread ).
This will monitor the batteries condition and you can monitor it yourself at anytime if you wish.
Also, it will send a notification to your phone, if the battery state drops below a safe working level.
Then you will have some recorded historical data / proof / data sorted on an App on your phone ?.
Or you could pop into Halfords, who will carry out a free health check on your 12 battery also.

 

[Nickel]

Thanks for that. I'd missed seeing that in the thread - I thought it was about connecting to Android Auto via Bluetooth...

I've ordered a BM2 from the Great River in the Clouds. (Other South American rivers are available..)

 

[Michael A]

Car is a ZS Trophy LR, just under a year old.

We have started seeing messages that the "Low voltage battery needs charging, do not leave car more than 3 days unused." Or words to that effect.

Yesterday evening we parked up with the battery registering 13.8V. Later in the evening it was down to 13.0V, measured via the MG Smart app.

Now (lunchtime), it's down to 12.2V.

As far as we can tell, nothing we control is on. And the car hasn't been used since we parked.

Can anyone shed any light?

Nick

Same problem! There is something wrong either with the charging or there is current drainage somewhere. The Dealer has not been helpful at all. It’s a ZS EV 2021.

 

[charlesp]

MG ZS SE long range. Collected from the service department after repair to rear door window - new motor and loom - so had been in the dealer garage for a week. Arriving home I got the low voltage message when opening the drivers door to leave the car. Have had it several times until I did a charge from 20% to 80%. Haven’t had a message since.

 

[Fads54]

Car is a ZS Trophy LR, just under a year old.

We have started seeing messages that the "Low voltage battery needs charging, do not leave car more than 3 days unused." Or words to that effect.

Yesterday evening we parked up with the battery registering 13.8V. Later in the evening it was down to 13.0V, measured via the MG Smart app.

Now (lunchtime), it's down to 12.2V.

As far as we can tell, nothing we control is on. And the car hasn't been used since we parked.

Can anyone shed any light?

Nick

I had the same problem. The low voltage battery was flat when we got back from holiday at Heathrow. It turned out to be linked to the sound system that was on and draining the battery even though it appeared to be off. Software update cured the problem. Just to be safe I carry a small rapid charger in the car in case it happens again.

 

[Bandanaman]

You should be seeing around 13.8v when the car is charging the battery, and above 12.6V when the battery has been stood more than 24 hours without use.. This would indicate a battery near 100% health... You should only really start worrying if after 24 hours your still loosing voltage. Around 11.9v you should start to worry, as the battery is then entering a discharged state, and if you see around 10.9v then the battery will be goosed at that point, and will probably no longer hold a charge, even if you attempted a recharge.

From the reading you have given, I'd see no issues with your battery or state of charge shown in the app.

 

[sandra54]

Car is a ZS Trophy LR, just under a year old.

We have started seeing messages that the "Low voltage battery needs charging, do not leave car more than 3 days unused." Or words to that effect.

Yesterday evening we parked up with the battery registering 13.8V. Later in the evening it was down to 13.0V, measured via the MG Smart app.

Now (lunchtime), it's down to 12.2V.

As far as we can tell, nothing we control is on. And the car hasn't been used since we parked.

Can anyone shed any light?

Nick

I had the same thing, the warnings started after I had to be rescued by the AA when it wouldn’t start. Taken to the garage where they charged the battery. The car continued to give the warning, back to garage, decided it was a sensor! The car was back into the garage overnight on 2 further occasions as the warning messages changed to “ pull over when safe to do so “ and something about unsafe something or other! before they replaced the 12v battery. Why it wasn’t replaced immediately I’ve no idea . No problems since.