12v dead battery and wife locked in the car! - Welcome home!!

[lfc958]

The thing that worries me about these is that I hear they tend to die permanently if not kept charged up every couple of months. I'm likely to forget all about it. I need something that won't be ruined if I leave it untouched for a long time.

Are you referring to the NOCO? Yes there is that given you would have as an insurance and we all know what happens if you dont keep up the premiums
Checking is simple, power on and the colour indicator bar will tell you how much is left, can then use supplied USB to C connector to top up, from virtually empty around 10% to full takes around 4 hrs, although we never let it get that low .
Our work one has a button that uses the jump pack as an external battery to jump start if the normal mode that just takes current left in the battery and boosts it up as it puts it back fails.

 

[GaryMG4]

I have a cheap Lidl/Aldi one about the size of a small brick. I bought it to originally to power a telescope, but never used it for that it sat fully charged for a year or so unused. I then had cause to jump start our Honda, it worked fine then and on a couple of occasions since then. It is an LFP battery inside though.

 

[dawson2099]

After a 7day holiday, return to Gatwick Long Stay South car park to pick up our MG4. Eventually find car which isn't responding to the fob to show me where she is.
Doors - don't open!
Call to the AA - 2hrs atleast!
I can't open the drivers door with the emergency key so go and guard our luggage by Bus stopD12 whilst wife has a go!
Get a phone call from the wife- she's manged to use the manual key and open the drivers side door, got in, door closed behind her and now she's locked in the dead car with both key fobs!
Panic call to AA, they set us as a priority!

Drag bags to the car. Wife crawls inside the car to the boot and manages to unlock boot manually using the emergency key from inside! Using the latch outside, I manage to open the boot and get her out!

Immediate panic over!

Still have a 3hr drive home to Dorset!

AA man arrives after 2hrs, boosts the 12v battery and the car comes to life!

First time we've take the car far away from home and parked for 7days!
HV battery was parked with 37% life! Have retrospectively checked 12v battery leads all look ok.
Had a software update to fix Bluetooth issues 1 week ago!
Could the new R33 update be causing battery drain?
Separately, I've read other posts about 12v batteries that die after 2 days or even 2hrs.
To be honest although I enjoy driving the MG4 I'm now a disappointed and concerned owner. Car bought new in April 23.
Will be calling Hendy Poole on Monday!

Similar experience. Car on driveway unused for 6 days. SOC 80%. No response to fob. Boost to 12v battery and all OK with battery immediately showing 12.7v. I suspected the issue because iSmart app stopped responding. Realised that I had left AA WiFi plugged into LHS USB socket and it was lit up. Anyone know if this socket is permanently powered as this may have run the battery down over 6 days.

 

[tsedge]

Similar experience. Car on driveway unused for 6 days. SOC 80%. No response to fob. Boost to 12v battery and all OK with battery immediately showing 12.7v. I suspected the issue because iSmart app stopped responding. Realised that I had left AA WiFi plugged into LHS USB socket and it was lit up. Anyone know if this socket is permanently powered as this may have run the battery down over 6 days.

I don't know for sure but it seems highly likely. But still, you'd think the car would top up as needed. What was the SOC when you rebooted it?

 

[AusCo]

This is a bit off topic. Just wondering about the manual re charging different types of batteries. I thought that lithium iron phosphate needed 'balancing' ie slow charging to 100% periodically, but ternary batteries ( as in the LR EV's) didn't. I don't know that the manual addresses both flavours in the same document ?

 

[tsedge]

This is a bit off topic. Just wondering about the manual re charging different types of batteries. I thought that lithium iron phosphate needed 'balancing' ie slow charging to 100% periodically, but ternary batteries ( as in the LR EV's) didn't. I don't know that the manual addresses both flavours in the same document ?

All batteries need some balancing - LFP guidance is weekly, NMC is monthly. Though people report balancing activity below 100% with the LR, the recommendation is to balance at 100%.

 

[Lovemyev]

All batteries need some balancing - LFP guidance is weekly, NMC is monthly. Though people report balancing activity below 100% with the LR, the recommendation is to balance at 100%.

My balancing process on our LR is not even close to once a month TBH.

 

[Rolfe]

My balancing process on our LR is not even close to once a month TBH.

I don't know what happens to the LR if you don't balance it, but in the SR it appears that the GOM starts lying to you, usually overestimating the SoC and the range, until it's nearly empty and the terminal fall-off in charge triggers a recalculation and a nasty surprise. I think that's what happened in a few cases where drivers recorded their dead battery disaster on video.

The LR may be different, or maybe you never play it close enough to the wire for that to matter, but I imagine they tell you to balance every month for a reason.

 

[siteguru]

The NMC battery in the LR models has a bigger buffer than the LFP seems to have ... 61.7 of 64 vs 50.8 of 51 (kWh). Plus the nature of cell voltage reduction in NMC means it is much easier to determine state of charge than in LFP (which holds pretty much a stable voltage and then falls off a cliff at low SoC).

 

[Rolfe]

So what is the purpose of the balance charge apart from that, then?

 

[fnegroni]

So what is the purpose of the balance charge apart from that, then?

As found on "another forum"TM

With thanks to @arg this is a direct quote from the "battery balancing - what's it for" thread in the Tesla forum dtd 2/8/2016

"Your battery pack is comprised of 96 cell groups, wired in series. The function of balancing is to ensure that those 96 groups are all at exactly the same state of charge. Normally, with the cell groups wired in series, any charge or discharge current flows through all of them equally and so they should in theory always remain at the same state of charge. In real life, things don't quite behave according to theory - charging is not 100% efficient, and the efficiency will vary between cells, and so after a while some will be slightly more charged than others.

The battery pack has a set of bypass circuits round each cell group that can deliberately waste (some of) the charging power heading for that cell group as heat, allowing the charge to be targeted at the group(s) that need it to bring them all up to the same level. The balancing circuit only allows a very small charging current to be targeted in this way, so balancing is slow if there is a significant imbalance to be corrected.

If the pack is out of balance, the effect is a temporary loss of capacity: when charging, you have to stop when the most highly-charged cell group hits the maximum allowable voltage, and when discharging you have to stop when the most lowly-charged cell group hits the minimum allowable voltage (in either case the cells would be damaged if you didn't stop). So if, for example, there's one cell group with 1% less charge in it than the others, then you can only use 98% of the total available charge, since you have to stop when that group gets empty (the others all still have 1% in them that you can't make use of) and when charging you have to stop when that one group is only at 99% (the others have all reached 100% so you can't carry on). Balancing allows you to use the full capacity again.

The main impact of never balancing is that it will take a very long time to balance when you do eventually get around to it. If you are never balancing, then presumably you are never needing 100% of capacity, so the fact that you've lost access to it doesn't really matter.

Arguably, using a pack that's severely out of balance puts a tiny bit more wear on it (for the same charge/discharge cycles) than if the pack was well balanced - but the effect is so small I'd be surprised if you could measure it let alone have an effect that's worth bothering about."

 

[AusCo]

All batteries need some balancing - LFP guidance is weekly, NMC is monthly. Though people report balancing activity below 100% with the LR, the recommendation is to balance at 100%.

Ta. Good to know

 

[Rolfe]

As found on "another forum"TM

With thanks to @arg this is a direct quote from the "battery balancing - what's it for" thread in the Tesla forum dtd 2/8/2016

"Your battery pack is comprised of 96 cell groups, wired in series. The function of balancing is to ensure that those 96 groups are all at exactly the same state of charge. Normally, with the cell groups wired in series, any charge or discharge current flows through all of them equally and so they should in theory always remain at the same state of charge. In real life, things don't quite behave according to theory - charging is not 100% efficient, and the efficiency will vary between cells, and so after a while some will be slightly more charged than others.

The battery pack has a set of bypass circuits round each cell group that can deliberately waste (some of) the charging power heading for that cell group as heat, allowing the charge to be targeted at the group(s) that need it to bring them all up to the same level. The balancing circuit only allows a very small charging current to be targeted in this way, so balancing is slow if there is a significant imbalance to be corrected.

If the pack is out of balance, the effect is a temporary loss of capacity: when charging, you have to stop when the most highly-charged cell group hits the maximum allowable voltage, and when discharging you have to stop when the most lowly-charged cell group hits the minimum allowable voltage (in either case the cells would be damaged if you didn't stop). So if, for example, there's one cell group with 1% less charge in it than the others, then you can only use 98% of the total available charge, since you have to stop when that group gets empty (the others all still have 1% in them that you can't make use of) and when charging you have to stop when that one group is only at 99% (the others have all reached 100% so you can't carry on). Balancing allows you to use the full capacity again.

The main impact of never balancing is that it will take a very long time to balance when you do eventually get around to it. If you are never balancing, then presumably you are never needing 100% of capacity, so the fact that you've lost access to it doesn't really matter.

Arguably, using a pack that's severely out of balance puts a tiny bit more wear on it (for the same charge/discharge cycles) than if the pack was well balanced - but the effect is so small I'd be surprised if you could measure it let alone have an effect that's worth bothering about."

I meant to say, thanks for that.

 

[Exdro]

After a 7day holiday, return to Gatwick Long Stay South car park to pick up our MG4. Eventually find car which isn't responding to the fob to show me where she is.
Doors - don't open!
Call to the AA - 2hrs atleast!
I can't open the drivers door with the emergency key so go and guard our luggage by Bus stopD12 whilst wife has a go!
Get a phone call from the wife- she's manged to use the manual key and open the drivers side door, got in, door closed behind her and now she's locked in the dead car with both key fobs!
Panic call to AA, they set us as a priority!

Drag bags to the car. Wife crawls inside the car to the boot and manages to unlock boot manually using the emergency key from inside! Using the latch outside, I manage to open the boot and get her out!

Immediate panic over!

Still have a 3hr drive home to Dorset!

AA man arrives after 2hrs, boosts the 12v battery and the car comes to life!

First time we've take the car far away from home and parked for 7days!
HV battery was parked with 37% life! Have retrospectively checked 12v battery leads all look ok.
Had a software update to fix Bluetooth issues 1 week ago!
Could the new R33 update be causing battery drain?
Separately, I've read other posts about 12v batteries that die after 2 days or even 2hrs.
To be honest although I enjoy driving the MG4 I'm now a disappointed and concerned owner. Car bought new in April 23.
Will be calling Hendy Poole on Monday!

How do you manage to lock your wife in the car? Could prove useful

 

[Trebor]

After a 7day holiday, return to Gatwick Long Stay South car park to pick up our MG4. Eventually find car which isn't responding to the fob to show me where she is.
Doors - don't open!
Call to the AA - 2hrs atleast!
I can't open the drivers door with the emergency key so go and guard our luggage by Bus stopD12 whilst wife has a go!
Get a phone call from the wife- she's manged to use the manual key and open the drivers side door, got in, door closed behind her and now she's locked in the dead car with both key fobs!
Panic call to AA, they set us as a priority!

Drag bags to the car. Wife crawls inside the car to the boot and manages to unlock boot manually using the emergency key from inside! Using the latch outside, I manage to open the boot and get her out!

Immediate panic over!

Still have a 3hr drive home to Dorset!

AA man arrives after 2hrs, boosts the 12v battery and the car comes to life!

First time we've take the car far away from home and parked for 7days!
HV battery was parked with 37% life! Have retrospectively checked 12v battery leads all look ok.
Had a software update to fix Bluetooth issues 1 week ago!
Could the new R33 update be causing battery drain?
Separately, I've read other posts about 12v batteries that die after 2 days or even 2hrs.
To be honest although I enjoy driving the MG4 I'm now a disappointed and concerned owner. Car bought new in April 23.
Will be calling Hendy Poole on Monday!

I had the same problem with my brand new ZS.
Returned from 5 days away to find car would unlock but not power up. Long story short 12v battery flat, AA called and charged it all powered up ok. I was asked if I had a problem with the radio, which I had. Apparently this can cause the battery to drain. The radio was fine for a few days, now back to the the same problem with stations fading out and now I’m unable to change stations or from DAB to FM etc.
I’m also in Poole and will be contacting Hendy. ( Car is a lease car and not supplied by Hendy Poole).
Please, no comments about having a 10mm spanner to disconnect the battery to reset the system. I’m not starting to do that with a 73 plate car and 700 miles on the clock. Not impressed.

 

[Ian W]

I've not seen any reason to suspect that there's anything wrong with mine. However, I made a point of not even opening the app all the time I was away.

I haven't checked, but don't the reading lights go off anyway when the car is locked, even if you left them on?



Very helpful, thank you.

Hehe. I'd only had my zs ev for 2 weeks when went to UK for 8 weeks (from nz). You know, new toy and all that, I checked it each day but after about 5 days it stopped responding. All the rest of the time I was wondering if I'd flattened the 12v or whether it'd decided to ignore my pointless enquiries. Anyway, back home after the 8 weeks all was tickety boo, including the12 v battery. I'd left the car at about 80% though. Thinking about getting a booster battery nevertheless, these forums are very useful for being prepared in advance. Thanks.

 

[Rolfe]

I booked a secure long stay car park space at the airport, and knowing the car was in there enabled me to leave the app alone. The original plan had been to park in the street outside my friend's house and get a taxi to the airport, but I'd have been concerned enough about that I probably couldn't have left the app alone.

 

[drugrunner]

Is there a problem keeping a charged Lithium battery in your car whilst you are away for an extended period of time e.g. When parked in an airport car park? I'm thinking fire risk and insurance cover...

 

[Lovemyev]

Mine is kept under the drivers seat at all times.
Yes - Like everything else, I guess some element of risk is possible, but remember the car is sitting on a traction battery that has MUCH more capacity than a small 12 volt booster pack !.
You carry your phone in the car and even a tablet or lap top, I mean how far to you go frankly ?????.

 

[JonEV]

I had the same problem with my brand new ZS.
Returned from 5 days away to find car would unlock but not power up. Long story short 12v battery flat, AA called and charged it all powered up ok. I was asked if I had a problem with the radio, which I had. Apparently this can cause the battery to drain. The radio was fine for a few days, now back to the the same problem with stations fading out and now I’m unable to change stations or from DAB to FM etc.
I’m also in Poole and will be contacting Hendy. ( Car is a lease car and not supplied by Hendy Poole).
Please, no comments about having a 10mm spanner to disconnect the battery to reset the system. I’m not starting to do that with a 73 plate car and 700 miles on the clock. Not impressed.

Is this a Dorset wide epidemic? Also in Poole, 3 days and my MG4 failed to do anything. The AA chap said he was seeing it a lot. Once "jumped" I had to leave it unlocked for a few hours and the 12V system charged itself.
Same DAB issue before, although sorted following this debacle. I assume the infotainment was rebooted and cleared the error.