Dead 12 volt battery

[CDR]

Sorry, missing something here - what do you leave plugged in the USB port - a powerbank? And is so, how does that help if the battery is completely flat, as you mentioned - USB is turned off when the car is shut/locked, so unless it's force unlocked, and a jump start connected on the 12v battery, run mode/acc turned on USB would not be activated, by when you may already be charging the car from the main battery? What am I missing?

Hello to you too.
I leave it plugged in all the time so it continuously trickle charges "WHEN I DRIVE THE CAR". There fore the bank is charged if I need it. It kinda saves on charging it in the house.
Maybe next time don't be so ignorant in the way you ask for advice and just ask nicely.

 

[Goodc2]

My previous car was a Mitsubishi Outlander Phev (fortunately that didn't happen to me) that had similar issues with low/dead 12volt auxiliary batteries that caused lots of error messages and Start Problems, according to the Outy Forums. The answer was to carry a set of jump leads that can be used to overcome the issue, I would be tempted to have the same in the boot ready for the MG, if a similar issue was to occur.

 

[Mark Holmes]

I have a charged jump start pack just as a precaution, but it’s also a torch and can charge other devices through its attachable cigarettes lighter connection and USB ports.

 

[auris]

Hello to you too.
I leave it plugged in all the time so it continuously trickle charges "WHEN I DRIVE THE CAR". There fore the bank is charged if I need it. It kinda saves on charging it in the house.
Maybe next time don't be so ignorant in the way you ask for advice and just ask nicely.

Hi again, sorry @CDR - I did not mean to sound mean (heh), I just did not understand the use of it, thanks for explanation, think I get it now - power bank is not a get out of jail free card, I.e. one would still need to hack into the vehicle, but there is some spare power once you're in it.

 

[CDR]

Ah no bother at all. This is a brilliant platform for solving problems either short term or long term

 

[Phil Hayward]

My battery reads 13.5 v when charging, seems a bit low. I used a small gel battery to jump start it.
I have seen some versions in other countries charge to 14.5 v

 

[lee graham]

My 12v battery fluctuates between 13 and 14v. I believe this is normal and expected.

 

[KasEV]

My previous car was a Mitsubishi Outlander Phev (fortunately that didn't happen to me) that had similar issues with low/dead 12volt auxiliary batteries that caused lots of error messages and Start Problems, according to the Outy Forums. The answer was to carry a set of jump leads that can be used to overcome the issue, I would be tempted to have the same in the boot ready for the MG, if a similar issue was to occur.

Well, I understand one needs to be cautious or even adopt a jsut in case appoarch but for me personally unless there is an obvious cause of a flat 12volt battery such leaving a boot light on, a dead 12VB should never occur in a BEV so my approach is to charge the batteries if there is an obvious cause and send the car in for a check if there is no obvious cause.
Looking at forums with discussions on dead 12VB it seems those who claim they have this problem never seem to have had their vehicles actually checked for a cause.
So am not too sure if the issue is with particular cars or particular individuals.
Surely if it is an issue with a car particular brand then one will expect the manufacturer to rush with a solution.

 

[MEH]

Charging rates
13.8-14.5 V for a Calcium Battery
12.9-14.1 V for a Lead Acid Battery

 

[Dr Ravindra Vottery]

Hi. Has anyone else experienced to have a dead car because the 12 volt battery is suddenly very low?
We didn't use the car for 5 days, and when it was time to use it again, we couldn't open the car. Luckily I have seen a video on how to enter the car with the secret key. But everything was dead in the car, the 12 volt battery measured 2.85 v when we measured it.

Hi, I am from Hyderabad, India. I have both MG ZS EV and Hyundai Kona. Kona's 12v battery gets charged by high voltage battery periodically. I need not bother for 1 to 2 months. With MG, I faced a totally dead battery if I don't switch on the car for 9 to 10 days. This happened multiple times without any accessories on. I don't use any.
I got a good jump starter and jump start car myself.
Asked for a new 12v battery as this one gives low voltage message every 2 days despite 35km run daily. Faced this problem in a new MG.