Winter coming 12V battery

[Jto]

Hi all
Winter is coming and just like ICE the 12V battery needs to be monitored and a lot of people over look this. Up until last month I used my car every day and did 18 miles each week day, now I have retired the car is not used every day and also a lot of short journeys so the 12V battery may not get the charge it needs and the voltage will slowly drop and then one day the car will not start.
The cars made before the app you need to monitor by look for the status of charge in information screen, check this up on the MG website and user manual. Cars with the app can scan the car and check the 12V battery status at the bottom of the list, do this after being standing in the off and lock for 10 minutes or so.
A good 12V battery should be showing 13V, if a battery shows 12V take the car for a good run to bring it up, the 12V battery is charged when charging the HV battery but you may only do the every two to three weeks but the 12V battery is been used when the car is off so slowly discharging. You can buy a an off board charger to boost the battery.

If your car is three to four years old your battery may keep dropping to 12V more often and this is sign it’s not as efficient as it was and may be time to replace the battery before it fails on you. Before you start shouting I have had a battery on mine for 7 years the above is subject to make and build quality and use.

 

[5teep]

Your ZS should be monitoring and charging the 12V battery as needed, even when the car is off.

 

[Jto]

Your ZS should be monitoring and charging the 12v battery as needed, even when the car is off.

Thanks I know that, but over the years been on here there have been many people caught out by 12V batteries failing through not monitoring the voltage drop, the car will do the day to day but has no way to tell you the battery is failing and then the day you need the car it failed.

 

[Lovemyev]

Some good tips here .
If you suspect that your 12 volt battery status is a little low, then you don’t need to necessarily have to “take it out for a run”.
Just having the car in “ready” mode has the same effect.
ICE powered vehicles have an alternator to charge the 12 volt battery, driven by the ICE.
Going for a run is beneficial in this case.
In ready mode, the traction battery is providing a charger to the 12 volt battery.
“Top Tip” - If you are a low user case, not covering a lot of miles, then using a smart charger a couple of times a year is a good idea.
Your 12 volt battery will love you for it .
It will limit the risk of getting caught out on the day you need the car.
A battery booster pack is a brilliant antidote when this happens and is a good investment.
Could save a long wait for the recovery people !.

 

[Martinonline]

For clarity, in the MG4 you do not need to be in 'Ready' mode just powered up to charge the 12V battery from the HV battery. (The car drops out of 'Ready' mode once you leave the seat but it stays powered up until you power it down from the info screen or you lock the car.)

EDIT: Must check, it may be the car comes out of 'Ready' mode when you open the driver's door.

 

[Lovemyev]

Same as the S5

 

[Ian Key]

The MG4 also charges the 12V battery from the main battery when it's locked. I have previously posted screen shots of my battery showing 14.7V after being unused for over 24 hours on the MG4 forum. If yours doesn't then a software update might be needed.

I assume the MGS5 does the same but as the battery voltage isn't available to view on the app I can't say for certain.

 

[pollenface]

my 12v battery charges every day with a solar panel and mppt

 

[Lovemyev]

I assume the MGS5 does the same but as the battery voltage isn't available to view on the app I can't say for certain.

It a strange thing to omit it from the health check pass on the App for the S5 ?.
12 volt battery status is an important one .
Why offer the facility to check it when your IN the car, but not OUT ????.

 

[Lovemyev]

I guess if you are a low milage user case and are concerned about keeping tabs on the 12 volt health on your S5, you might consider fitting one of these little devices onto your 12 volt battery .
Not that expensive to buy and an easy DIY job to fit in only a couple of minutes.
You install a free to download App on your phone and you’re good to go !.
You are then able to check on 12 volt battery status when you like.
It will even send a notification to your phone when the status of the battery drops to low.

Here is video showing it being installed and working.
Under the “more” tab, there is links for the unit and were to down load the App.