How long should the 12 volt, battery last ?

And many more.

We have an MG ZS EV '70' plate so over 4 years old now and 22k miles. I've never had any problems with the 12V battery.

I have fitted a Bluetooth battery monitor to keep an eye on things and alert me to any problems. They're £30 on Amazon.

Watch Mr EV's video to see what it's all about - Battery Monitor. and the one I bought is here.

Here's my data for the last 15 days (well, I haven't sync'd it for a few days but you get the gist).

I think that is too much information! Dropping to 12V regulary is not what I would like to see!

I really like the 12V monitoring capability of a Victron 75/15 mppt, shows 30 days history with daily highest & lowest voltages.

I think it's good practice to change the 12V battery at the first sign of weakness, as others have stated, carry a lithium jump starter to get you out of trouble.

If you're using the car regularly, the regular charging of the 12V battery provided by the car will help keep it healthy and lower the rate of sulfation/capacity loss.

Our last car was a Honda Diesel. We bought it new and it was registered in November 2009.

We found out it was a 2007 build and had been hanging around in the dealership network. Consequently, the battery was goosed, although, this wasn't mentioned when we bought it. But I negotiated some "cash back" to replace it, as it kept letting us down.

I bought a Bosch S6 Stop/ Start battery from Tayna which was absolutely amazing and did the car proud from around 2 months old until after we got the MG4 in mid 2023. In fact we sold the car with it still going strong. By this point, the car had done 175,000 miles, nearly all of them with the Bosch battery.

There is no doubt there are good batteries and bad batteries, often down to how they were treated before use in a car. If there is any doubt about any particular battery, best to just change it for a new one. I also recommend Tayna who do next day delivery.

I had to change my 12v battery after 4 years or so. ZS EV CV70.

I suspect the EO Charger might have something to do with it, by leaving the car switched for a long period, The Charger went *its up at the same time. MG dealer charged me £200+ for a replacement...

I generally seem to manage 7 to 9 years. I use a battery conditioner if the car is idle for long periods.

However when I changed my Morgan last July the car had sat at the dealers for 9 months. The dealer told me they kept their cars on conditioners . Six months later at just under 2 years old it failed.

I didn't think it could be the battery so called out the AA. Their guy told me AGM batteries, which this was, often fail at 2 years. I too went to Tanya for a replacement.