Brand new 12V battery discharging

[hmadsen]

ICE cars also suffer battery problems if left for weeks without use, mainly due to alarms and other continuous battery loads.
The solution is obviously a maintenance charger, but this is only possible if mains power is close and there are no issues with cables, etc.
Another option could be a PV panel and charge controller- I use one for my 1950 MG TD and it works very well for the long periods when the car is unused in a remote garage. For the ZS, it may be enough to put the PV panel under tbe windscreen?

If the car has the cigarlighter plug connected directly to the 12V battery, even when power is off, he might even get away with just buying something like this and plugging it into the cigar lighter socket.

Solar charger for car

I would imagine that the Cigar lighter is on the ignition 12V circuit.

That being said, it would still be possible to wire a device like this, to the battery and get a wire through to the cabin.

A bit of a shame, the ZS EV does not continuously measure the voltage on the 12V battery and just top it off when it gets low, even if the car is parked up. I know this is how other car brands make sure the 12V battery does not go flat, even if you park the car up at the airport for 2 weeks while you go to Ibiza.

 

[Lovemyev]

even if you park the car up at the airport for 2 weeks while you go to Ibiza.

A 12 volt battery booster ( jumper ) pack is always a brilliant and worthwhile investment.
I have one stored under the drivers seat at all times.
Then should you get caught out by a flat battery any time, then you can use the emergency blade to enter via the driver's door, then release the bonnet and attach the booster pack.
You are on your way in minutes, rather than waiting for the recovery people to arrive.
We have a second unit in the back of my wife’s Fiat 500 ICE for the same reasons.
I have never found it necessary to use them on either car ( yet ) but it has helped out about four stranded people in the last 3 years.
All cars were ICE powered OBTW !.

 

[Coulomb]

A bit of a shame, the ZS EV does not continuously measure the voltage on the 12V battery and just top it off when it gets low, even if the car is parked up.

I have suspected this on my Mark 1 ZS EV, but assumed that it would be fixed in the facelift model.

Has the lack of 12V top-up when parked been confirmed for either ZS EV model?

 

[Lovemyev]

I have suspected this on my Mark 1 ZS EV, but assumed that it would be fixed in the facelift model.

Has the lack of 12V top-up when parked been confirmed for either ZS EV model?

Having owned both the Gen1 & Gen2 models of the ZS EV I am totally convinced that the 12 volt battery is only receiving a charge, when the car is in READY mode and not in STANDBY mode.
If you do have the car in standby mode only and have the radio running etc, you can see via voltage gauge in the dash panel, that NO charge is entering the 12 volt battery at all.
I have come to the conclusion that this is the reason WHY the car has been designed to shut down the 12 volt draw after about 10 minutes in standby mode.
This is in order to prevent the driver running down the 12 battery when parked up and in standby mode to run the radio etc.
Of course, when the system shuts down after 10 minutes, you could reboot the car back into standby mode once again.
This practice will give you another 10 minutes of run time of course.
However if you continue to keep conducting this looping cycle, you do run a big risk of depleting the 12 volt battery .
Personally I find that the standby mode has little value really. For this very reason, I always just boot into READY mode regardless.
If I am sitting waiting to pick up a passenger, then I just leave the car in READY mode ?.
You can clearly see the 12 volt battery status charge rate is then at about 14.0 Volts ( about the same as an ICE car would display with an alternator ),
Of course, with the Gen2 model the radio continues to play even when the car is closed down and you have left the car !.
Only locking the car with the fob, we then close down the 12 volt system powering the radio etc instantly.
If you failed to lock the car, the radio will continue to play for the same ( approx ) 10 minutes, then it will time out and shut down.
It does seem like a strange way of doing it, surely everything should shut down at the point when the car is powered down ???.
But without this built in 10 minute delayed shut down time, you could in theory forget to lock the car and walk away and then return to find the radio has then completely depleted the battery.

 

[pollenface]

For the ZS, it may be enough to put the PV panel under tbe windscreen?

Absolutely,

Have done so with many cars with only a 10W panel.

 

[Nickel]

This is going to sound strange.

There is/was a bug in the ZS software which causes the DAB radio to continue to search for a "missing" DAB channel even when the car is off. Which drains the battery.

I had this happen to me after a trip from Swansea to the Midlands, when the radio ended up searching for a Birmingham station, having lost the South Wales station I had been listening to.

I had awful problems with the 12V battery after that. I don't use the radio, or any other audio often, so didn't tune away for weeks. Sadly, I can't be 100% sure of cause, as my dealer swapped out my battery around the same time I discovered the bug.

If you are a DAB user, check your radio isn't doing something similar. May or may not be relevant. Easy fix if it is!

 

[hmadsen]

Absolutely,

Have done so with many cars with only a 10W panel.

Yeah it does not need to be very highly rated to keep the battery topped up.

If fixed into the car and wiring routed and fixed, this would be a lot easier in the long run, compared to having to remember to connect a wall outlet trickle charger.

 

[pollenface]

If fixed into the car and wiring routed and fixed, this would be a lot easier in the long run, compared to having to remember to connect a wall outlet trickle charger.

agreed, I have a 190 W panel on the roof of my ICE car and an MPPT under the passenger seat to keep both batteries topped up. I'd love to do similar to the EV but the wife won't let me

 

[hmadsen]

agreed, I have a 190w panel on the roof of my ICE car and an mppt under the passenger seat to keep both batteries topped up. I'd love to do similar to the EV but the wife won't let me

Have you physically mounted a 190W solar panel on something (Roof rack ?) on top of your car ?

TBH that sounds a bit extreme for me, especially on the ZS EV, that has a glass roof (Atleast the one i will get, has)

 

[pollenface]

Have you physically mounted a 190W solar panel on something (Roof rack ?) on top of your car ?

TBH that sounds a bit extreme for me, especially on the ZS EV, that has a glass roof (Atleast the one i will get, has)

It is physically mounted and able to be tilted for carrying gear or building supplies, the ICE vehicle is setup for camping.

We have the Australian ZS Essence model which has the roof rails, and roof racks are available for it. Not sure how you would mount something without the roof rails.

 

[hmadsen]

It is physically mounted and able to be tilted for carrying gear or building supplies, the ICE vehicle is setup for camping.

We have the Australian ZS Essence model which has the roof rails, and roof racks are available for it. Not sure how you would mount something without the roof rails.

No no i understand and if it is used for camping i understand it, but i would tend to agree with your wife, if she does not really like to have a solar panel attached like that.

I would imagine it would also make some wind noise and create a bit of drag, even if mounted so that it with only hits the end.

I guess it's probably also different from country to country, if I did this in the Scandinavian country I live in, I would certainly have people looking funny at me

 

[fred12345]

This is going to sound strange.

There is/was a bug in the ZS software which causes the DAB radio to continue to search for a "missing" DAB channel even when the car is off. Which drains the battery.

Is this on Mk1 ZS? My 2022 Mk2 turns off the screen and infotainment completely off when you lock the car or within 10 min of turning the car off... I don't see how would we check the radio draining the 12 V battery unless connecting multimeter to the infotainment system ... ? How did they figure out it was your radio?

 

[rcworcs]

Measure the terminal voltage of the fully charged 12 V battery. To check it’s charged ok. Around 12.6-12.8V ish for AGM type ( 30 mins after disconnecting charger)
Then I would recommend using a current clamp meter on the 12 V battery to see if there is a current draw present when locked. From this you can calculate the expected life of the battery charge using the Ah rating of the battery. Ah/current draw = hours life. Obviously if it’s only a day or 2 then something is wrong .
Check display/ radio/boot light / cabin light goes off when locked up etc.
Do you have any accessories fitted direct to the battery?

 

[Nickel]

Is this on Mk1 ZS? My 2022 Mk2 turns off the screen and infotainment completely off when you lock the car or within 10 min of turning the car off... I don't see how would we check the radio draining the 12 v battery unless connecting multimeter to the infotainment system ... ? How did they figure out it was your radio?

They didn't. The whole business was slightly woolly, which I'm sure won't satisfy some on here. That's why I was less than dogmatic.

It's a 2022, Mk2 Trophy LR, delivered in October 2022. All was fine with it, no problems with the 12V battery, or anything else, until August 2023.

We made a journey up to the Midlands which we'd done many times before. But unusually this one was on a weekday morning and we decided to listen to Popmaster on Greatest Hits South Wales, which is on DAB. I rarely use DAB round here - it doesn't like hills. We have a lot of hills. Anyway, the signal dropped out at the crucial moment, so we silenced the radio and carried on. Thought no more about it.

Shortly thereafter, we started having constant problems with the 12V battery going low. Nothing had changed in our driving habits. The dealer investigated, tested the battery, no probs. I started keeping a battery monitor on it. It was just fading away, but charging fine to full and testing fine..

The low point came when the car refused to start on holiday in early October. Fortunately by now, I was carrying a 12V booster as a precaution. Word to the wise - keep it in the passenger compartment as you can't open the boot when the 12V battery goes. Thankfully, my wife is more nimble than me.

Back to the dealer once home. Tested again, no problem. I played up because the one year battery warranty is about to expire. Fair play to them - they swapped the battery out as a precaution.

At almost exactly the same time I read about the bug I mentioned, so I checked my radio. Sure enough it was "tuned" to a Birmingham local station that it could not possibly receive down here. I put it on a National station and haven't had a moment's trouble since.

So, either a battery which tested good repeatedly was in fact a dud, and, my radio was not relevant, despite being in the exact condition that I had read caused a problem, having entered that condition a few days before the trouble started. Or it was the radio "at fault".

I know which I prefer, but I can't prove it. I've no intention of trying to recreate the problem. It may not recur anyway, as the car has been serviced twice since the problem started, so has likely been patched. I believe there is a patch, but obviously not everyone will have it.

Make of that what you will. But if someone has a mysterious 12V drain, it's the work of moments to check if the DAB radio is looking for something it can't find!

 

[janitor]

As Nickel said there’s a bug with the radio module, had the same problem with my MK1, battery went flat after about 6 months, got a new battery exactly the same thing happened, took the car to the dealer, they said there’s a radio bug, did I notice a error message about the radio, I said no I don’t use the radio, they said it hasn’t had the update, apparently MG have an update that solves the problem, had no problem since, but also got a battery monitor so I could keep a check on it. Might not be the same problem but sound very similar.

 

[Spinynorman]

As Nickel said there’s a bug with the radio module, had the same problem with my MK1, battery went flat after about 6 months, got a new battery exactly the same thing happened, took the car to the dealer, they said there’s a radio bug, did I notice a error message about the radio, I said no I don’t use the radio, they said it hasn’t had the update, apparently MG have an update that solves the problem, had no problem since, but also got a battery monitor so I could keep a check on it. Might not be the same problem but sound very similar.

Do we know what software the bug relates to as, I have a similar problem but have had the comfort 2 upgrade and the BMS update that lets you charge with the doors unlocked.
BTW we shouldn’t confuse a maintenance charger with a booster - the maintenance charger is just a trickle charger and has no internal battery to boost the 12V battery if it goes flat. A Booster has an internal battery that you attach to the 12v as a supplementary source and allows you to start from a dead battery

 

[hmadsen]

Do we know what software the bug relates to as, I have a similar problem but have had the comfort 2 upgrade and the BMS update that lets you charge with the doors unlocked.
BTW we shouldn’t confuse a maintenance charger with a booster - the maintenance charger is just a trickle charger and has no internal battery to boost the 12V battery if it goes flat. A Booster has an internal battery that you attach to the 12v as a supplementary source and allows you to start from a dead battery

Those boosters seems very much overkill for an EV.

They have a Lithium battery with an extremely low internal resistance, meaning they can source A LOT of amps, but only for a short time. Have seen some of these, able to cold start a diesel in freezing temperatures.

The EV only need very little power to be able to wake the car and get the HV contactor energized, after that, the HV to LV charger takes over.

I would imagine a battery pack consisting of 3 fully charged 18650 cells would be enough to power the car for long enough, until the HV contactors close. (Depends on if the car tries to run lamps and "toaster" before the HV contactors are closed though).

 

[janitor]

Do we know what software the bug relates to as, I have a similar problem but have had the comfort 2 upgrade and the BMS update that lets you charge with the doors unlocked.
BTW we shouldn’t confuse a maintenance charger with a booster - the maintenance charger is just a trickle charger and has no internal battery to boost the 12V battery if it goes flat. A Booster has an internal battery that you attach to the 12v as a supplementary source and allows you to start from a dead battery

It’s nothing to do with the comfort or BMS update,it’s to do with the radio module, sometimes throws up a message about radio module not connecting, but as I don’t use the radio I didn’t notice any message, but dealer knew about it causing a flat battery, all been fine since.

 

[fred12345]

It’s nothing to do with the comfort or BMS update,it’s to do with the radio module, sometimes throws up a message about radio module not connecting, but as I don’t use the radio I didn’t notice any message, but dealer knew about it causing a flat battery, all been fine since.

What year is your car? was this an early bug that was then updated without making it public? I haven't heard of this until today from the above 2 posts ...

 

[janitor]

It’s a 70 plate, so it’s a September 2020, I read about it on here somewhere, just assumed it had already been done, as the car was an ex-demonstrator when I bought it, was told all updates had been done, when it went in after new battery went flat they said there is a update to fix the radio module initialising bug, been fine since.