First edition MG ZS EV flat battery - Help !!!!

[bollard1969]

Good evening everyone,

I last used my first edition MG ZS EV on Wednesday and came to the car tonight, but the car was not responding to my key at all. I thought it must be a problem with the key, so I got my partner's key, which I know had recently had a change of battery, but still the same issue.

After doing a bit of googling I managed to open the car with the hidden key in the key fob. I assumed for some reason the 12v battery was flat. I have a Halfords Automatic Battery Charger, but it says its not suitable for EVs.

Trawling through YouTube this doesn't seem to matter, so I attached the clips and the Battery Charging unit said it was charging. However it would only charge for ten seconds or so before stopping, the car horn beeps and then the charging starts again.

While opening the bonnet and seeing the battery, there was a load of gunk on the battery as you can see here

I can't really leave the car while the horn beeps every minute or so. Am I doing something wrong ? Any advice very gratefully received.

Cheers

 

[Gadget Geek]

My guess is, you need a new 12V battery. But you could try disconnecting both terminals and then charge it.

 

[ARealHuman]

Is that gunk some sort of discharge or oxidation, or grease to help keep moisture out (I used to smear Vaseline on these points on my bikes). I agree with @Gadget Geek - I'd disconnect the battery and charge it with a decent charger. Let us know how you get on.

 

[bollard1969]

What a forum. It is amazing how quickly people respond and so helpful too.

I have no idea what the "gunk" is. Its certainly nothing we've done. Car had its most recent service in mid May.

When disconnecting the battery I assume you mean I undo the bolts marked in the picture below.

And when you say a decent charger, do you mean that the Halfords charger won't suffice ?

 

[Lovemyev]

The “Gunk” on the battery looks like a “Fluid Film” type product.
Battery corrosion would be a crusty silver / green coloured power.
I would recommend just replacing the battery to be honest.
The 12 volt battery is the heart of any vehicle and even more important in a EV.
As others have said, you could try disconnecting both leads of the battery and then check the battery voltage with a volt meter.
You could then try carry out an overnight charge.
I assume you are using one of the newer type of smart chargers ?.
The older type battery chargers are not suitable for modern day batteries.
Have a look at “Tanya” on line for a new battery, they do next day delivery in the U.K.
You need to undo the 10mm nut on the pinch bolt on the clamps.
In your picture of the black negative clamp, it’s the one under where you have your battery charger clamp.
NOT the one highlighted in your photo !.
On the red positive lead, there is just one single 10mm nut to slacken off.
You have your red battery charger lead clamped onto it !.
Slacken the clamps and lift the leads clear of the battery, then connect your charger leads and charge over night.

 

[bollard1969]

So this is the battery charger I'm using.

And these are the bolts I need to disconnect

Just want to be sure. Thanks everyone for their help.

 

[Iain]

Good evening everyone,

I last used my first edition MG ZS EV on Wednesday and came to the car tonight, but the car was not responding to my key at all. I thought it must be a problem with the key, so I got my partner's key, which I know had recently had a change of battery, but still the same issue.

After doing a bit of googling I managed to open the car with the hidden key in the key fob. I assumed for some reason the 12v battery was flat. I have a Halfords Automatic Battery Charger, but it says its not suitable for EVs.

Trawling through YouTube this doesn't seem to matter, so I attached the clips and the Battery Charging unit said it was charging. However it would only charge for ten seconds or so before stopping, the car horn beeps and then the charging starts again.

While opening the bonnet and seeing the battery, there was a load of gunk on the battery as you can see here View attachment 19516

I can't really leave the car while the horn beeps every minute or so. Am I doing something wrong ? Any advice very gratefully received.

Cheers

Lots of useful advice already but I would also suggest when charging any 12v battery in situ it is a good idea to connect the negative lead from the charger to part of the car’s bodywork (a bolt head etc) rather than the actual negative battery terminal.

 

[Lovemyev]

So this is the battery charger I'm using.

View attachment 19518


And these are the bolts I need to disconnect View attachment 19519

Just want to be sure. Thanks everyone for their help.

They’re the ones !.
I have had a quick look on the Halfords web site and there is no reference to this unit being a “Smart Charger” and states it is not suitable for “Stop / Start” batteries.
Not that includes your car of course .
I would not recommend charging with this type of unit without disconnecting BOTH of the battery leads FIRST.
Smart intelligent chargers can analyse the condition of the different battery types and then provide a charge at a rate suitable to help recover the battery correctly.
Smart chargers can be used as a maintenance charger as well.
The CTEK smart units are compact and are popular with other members.

 

[bollard1969]

Ok little update.

This morning I disconnected both battery leads and tried to charge, with the negative lead from the charger attached to a part of the car's bodywork as advised.

The power light on the charger came on, but no charge button at all.

So it looks like I need a new battery.

I was just wondering what the deal is with AA membership after getting your MG serviced at a MG dealership, which I have seen talked about elsewhere. I think i got an AA card when I got the car, but no idea if I'm a member or not, now. Would be nice to have an expert opinion on what is wrong with the car. I don't want to throw away a perfectly good battery, if for some reason I've messed something up with my charging attempt.

I tried my reg no in the Tayna batteries website and it failed so I'll be giving them a call.

 

[steve748]

You should disconnect both leads from the battery, then connect the charger directly to to battery terminals. You have isolated the car that way.

 

[Lovemyev]

Ok little update.

This morning I disconnected both battery leads and tried to charge, with the negative lead from the charger attached to a part of the car's bodywork as advised.

The power light on the charger came on, but no charge button at all.

So it looks like I need a new battery.

I was just wondering what the deal is with AA membership after getting your MG serviced at a MG dealership, which I have seen talked about elsewhere. I think i got an AA card when I got the car, but no idea if I'm a member or not, now. Would be nice to have an expert opinion on what is wrong with the car. I don't want to throw away a perfectly good battery, if for some reason I've messed something up with my charging attempt.

I tried my reg no in the Tayna batteries website and it failed so I'll be giving them a call.

The text & video below offers some good advice on charging a 12 volt battery.
Regarding the MG Assistance ( A.A. ) cover.
If your car has been serviced at a main dealer at the correct periods laid down by the manufacturer, then this gives you access to this service.
You can call the number on the red card provided and give them your registration number.
They will tell you instantly if your car is covered.

How to Charge a Car Battery | Halfords UK

Keeping your battery healthy is crucial. Read on for a step-by-step guide on how to charge your car's battery.

www.halfords.com

 

[ARealHuman]

Hi - following up my earlier message and your reply I'd guess that a suitable charger sold by Halfords is going to be of at least reasonable quality. I was trying to make the point that a £4.99 charger from a supermarket, for example, isn't going to be that great. With some chargers, they have a battery test and conditioning feature which helps restore the battery before charging it (for example, I have an Optimate which I've used on my bikes as well as cars in the past). Something like this could be useful, however it may well cost more than a replacement battery, and if yours is dead, will only be a help in the future.

You've mentioned the AA/MG cover which I believe includes assistance at home (can someone confirm?). If so, put your battery leads back on, and give them a call! They will be able to confirm the 12v battery is dead and may offer advice on a replacement.

Hope that helps.

 

[bollard1969]

Good evening everyone,

I just thought I'd provide a little update and thank all the great people on this forum.

Once I attached both the leads to the correct terminals, the yellow charging light on the battery charger came on. Thanks for that stevebrobin. That was at about 10am this morning. I've been out all day and just come home and the yellow charging light is still on. If/when the charger says fully charged what are my next steps.

Simply reattach the battery to the terminals and hopefully it should start responding ? Do I need to drive the car around for a bit to really help the battery ?

 

[bollard1969]

The text & video below offers some good advice on charging a 12 volt battery.
Regarding the MG Assistance ( A.A. ) cover.
If your car has been serviced at a main dealer at the correct periods laid down by the manufacturer, then this gives you access to this service.
You can call the number on the red card provided and give them your registration number.
They will tell you instantly if your car is covered.

How to Charge a Car Battery | Halfords UK

Keeping your battery healthy is crucial. Read on for a step-by-step guide on how to charge your car's battery.

www.halfords.com

Yes, I have had two main services at the MG dealer in St Albans, but have no card. Should I just call the AA and see if I'm covered ? I'd like to get this sorted for any future issues.

 

[Lovemyev]

Yes, I have had two main services at the MG dealer in St Albans, but have no card. Should I just call the AA and see if I'm covered ? I'd like to get this sorted for any future issues.

Give them a call on the number below and quote your car’s registration number.

 

[Lovemyev]

Simply reattach the battery to the terminals and hopefully it should start responding ? Do I need to drive the car around for a bit to really help the battery ?

Switch off the charger at the wall socket and then disconnect the charger clamps.
Refit both battery leads and retighten them with the 10mm spanner .
The car should now be able to boot up if the battery has recovered.
If the battery quickly discharges again, then it will need replacing.
Once 12 volt batteries are run down to a very low level of charge, they sometimes can not be recovered.
Taking the car for a “run” has no real major benefits.
The 12 volt battery will be charging when the car is in ready mode or when the traction battery is being charged.
When the car is in standby mode, the 12 volt battery is actually being discharged.

 

[Coulomb]

Once 12 volt batteries are run down to a very low level of charge, they sometimes can not be recovered.

I would say often cannot be recovered. Though it is certainly possible that they recover with only minor loss of lifespan.

Edit: Assuming a lead acid battery (flooded or sealed), as is the case with original auxiliary batteries from MG.

 

[bollard1969]

Good Morning,

Ok I went to the car this morning and the charging light had gone off and switched to "ready and maintaining". So I reconnected the terminals and the car is now working normally again.

As someone of very limited car knowledge who isn't known for their technical prowess, this has given me a huge amount of satisfaction and it is thanks to all of you very patient people who kindly took the time to reply in this thread, that I was able to fix the car (for now).

I would still like to know what drained the battery so much and so quickly. I checked the roof light and the boot light, but they both turn off when I lock the car. I had left the sun roof open, but I wouldn't have thought that was an issue.

So the job now for me is to get sorted my AA membership.

Finally I just want to say a huge thanks to everyone on this thread, who has taken the time to reply. This really is such a great resource, but it is the people who contribute that make it so incredibly helpful.

 

[Lovemyev]

I had left the sun roof open, but I wouldn't have thought that was an issue.

You are correct, leaving the sun roof open has no adverse effect on the 12 volt battery state.
I very often leave mine tilted open to allow air flow.
There are a number of reasons that could have caused the battery to run flat.
If the battery is defective in any way, then the problem could return.
If so, it’s time for a new unit.
As a precautionary measure, I would make some enquires next week on prices etc just in case.
Some of the well know makes come with a 5 year warranty, which is handy to have.
I think the Bosch units and maybe the Exide units come with a 5 year warranty.
There are some other safe guards worth considering ?.
A lot of EV owners carry a 12 volt battery booster pack with them at all times.
Another option would be to install is a 12 volt monitoring device across the terminals of your battery.
You can download an App to your phone and if the device detects that the voltage is dropping too low, it will send you a notification message.
Here is a typical unit.

Battery Monitor BM2 device for Cars & Campervans 12V Battery/leisure battery tester Compatible with Android iOS and Ipad with bluetooth 4.0 and above. https://amzn.eu/d/5bu31Ej

 

[ARealHuman]

If you run any of the car accessories whilst not in ready mode, you'll be using the 12v battery which will drain quickly. So, for example, if you're sat in your car and wanting the radio on, make sure your vehicle is turned on as if you were about to drive, and that way power is drawn from the traction battery.