12V battery low warning light HS PHEV

[craig busbridge]

I got a beep at about 2am in the morning. I got up and took a short drive. That got me to the morning. I now carry a 12V LiFePo4 jump start pack, till I resolve this battery issue.

 

[Rayz]

Just received suggested battery from Tayna batteries. They suggest 027 ENDUROLINE CAR BATTERY 60AH. They also stock the same battery for start stop cars! One is wet technology the start stop one is agm. Not sure which I need. Any help would be appreciated.

I had the AGM 60amp from Varta a few months ago . Never had any trouble again it cost about £120 with 4 years warranty. It's worth the extra . But get an MG dealership to fit it or Electric car specialist. Because my car Is MG5 EV and that has a computer fitted as yours may have . The 12V System is the Main part to work any car, So get the best type of battery . The Blue reading on my car is the rectifier reading not the battery if your battery is fully charged it will read 13.8V if it reads 14v-14.6V your car 12V battery is being charged so if 14.6V the 12V battery has only around 20% or lower charge.

 

[mevvi1]

I had the AGM 60amp from Varta a few months ago . Never had any trouble again it cost about £120 with 4 years warranty. It's worth the extra . But get an MG dealership to fit it or Electric car specialist. Because my car Is MG5 EV and that has a computer fitted as yours may have . The 12V System is the Main part to work any car, So get the best type of battery . The Blue reading on my car is the rectifier reading not the battery if your battery is fully charged it will read 13.8v if it reads 14v-14.6v your car 12v battery is being charged so if 14.6v the 12v battery has only around 20% or lower charge.

Thanks for the advice, much appreciated. Gives me a way forward

 

[craig busbridge]

Today my PHEV started tooting the horn but at a very sickly volume. Nothing at all worked. It kept intermittently tooting at a more and more feeble effort. I climbed into back and manually (with a screw driver) opened the hatch, measured my battery voltage at about 7 volts. Called MG assist, a guy came and jump started with a hand carried pack. He made a statement, "it seems that the MG's sometimes just need a boost". The dash immediately displayed the normal 14ish Volts. This car is a little scary at times.

Oddly enough, after a jump start the battery seems to be holding a charge and the problem has gone away. It's like something was left on to cause the battery to go flat. It seems to me in a modern EV car it's impossible to leave something on, it's all taken care of for you. I'm beginning to suspect a random software issue, where something is left on on your behalf. This car seems to have numerous random software issues with the infotainment system, so anything could happen. I now carry a 12V portable LiFePO4 jump start pack, just in case. I'm a self help sort of person, roadside assist is not a solution. I now carry a hand tyre pump as the air compressor burned out on its first use. Lovely car to drive, very good economy, but somewhat frustrating with these "learning" issues.

 

[mevvi1]

Oddly enough, after a jump start the battery seems to be holding a charge and the problem has gone away. It's like something was left on to cause the battery to go flat. It seems to me in a modern EV car it's impossible to leave something on, it's all taken care of for you. I'm beginning to suspect a random software issue, where something is left on on your behalf. This car seems to have numerous random software issues with the infotainment system, so anything could happen. I now carry a 12V portable LiFePO4 jump start pack, just in case. I'm a self help sort of person, roadside assist is not a solution. I now carry a hand tyre pump as the air compressor burned out on its first use. Lovely car to drive, very good economy, but somewhat frustrating with these "learning" issues.

When my battery failed the AA informed that something had drained the battery. He ’boosted’ it for about 10 minutes, it started! On the upside it fixed the radio module issue! Lol. Agree yet another software issue. Shame as overall it is a very nice car to own.

 

[craig busbridge]

When my battery failed the AA informed that something had drained the battery. He ’boosted’ it for about 10 minutes, it started! On the upside it fixed the radio module issue! Lol. Agree yet another software issue. Shame as overall it is a very nice car to own.

Yeah,
I reckon owning an EV (or any modern vehicle), is like owning an iPhone 20 years ago. Nothing worked properly without jailbreaking. Rapid use of very modern technology can bring you a very glitchy vehicle. I just hope there isn't a fatal flaw.

 

[Lovemyev]

On the upside it fixed the radio module issue! Lol.

When the battery became drained so low, it was a little like disconnecting a heathy 12 volt battery for about 20 mins, then reconnecting it.
This situation is regarded as a master reset of the whole 12 volt system of the car really.
That would have likely restored the radio module in the first place.
As the SOC of the 12 volt battery became SO low, when when external power was supplied, it then automatically rebooted the system, together with the radio module of course.
That is why it suddenly rebooted the radio module and came back to life !.
Was this a phantom drain from the module, the real reason why it slowly drained power from the 12 volt battery in the first place and caused the flat battery ?.
If the radio module is in a frozen / looped state, it would be constantly tying to reboot /restore itself, could this be the reason WHY the 12 volt battery therefore, drained itself completely in the first place ?.

 

[craig busbridge]

Hard to know, but something flattened my battery and I truly think my battery is ok, after all it's a deep cycle battery. The problem is not resolved and it will happen again, hence I'm carrying a portable jump starter that I already owned. Next time I won't go to the battery in the back of the car, I'll go to the jump start + tag in the fuse box under the bonnet. A lot easier and quicker. With the PHEV the jumpstart doesn't even crank the engine, it just allows the system to reboot. Cars were a lot simpler 60s and 70s, nought ever went wrong, and you got a spare, jack and a wheel wrench. That's progress.