Caused by 12v battery or something else?

[HappyGoLucky]

I will try and keep a long story short. 3yr old ZS EV had its service and MOT and all good. Charged that night on our home charger and noticed charging speed was right down to 4.2. Wondered if it could've been some issue with any software update at the garage, but thought I'd see how it was next time. 2/52 later, charged again at home and was getting the same speed, home charger has been checked and all fine. Had a plan to call the garage on Monday and get them to investigate.
I had a 2.5hr drive with my little boy the next day, 15mins into it, it came up with a yellow warning of "vehicle system control fault, consult handbook". All seemed fine, so I nervously carried on driving (nowhere safe ti stop). 25mins from our destination i had ALL the warnings and the red one of 12v, stop safely. AA turned up, couldn't get the battery to hold a charge, recovery truck took me and the car back home and family collected my son.
Garage states it was all a 12v issue, replaced the battery, said it was all fine. Went to pick it up and same yellow vehicle control system fault there, red 12v light, wouldn't start. They're now saying a fuse has gone in the CCU and that's the issue. I had to pay for a new battery (car is 3yrs old), which would be acceptable if that was truly the reason for it all.
However, I can see no reason why this would affect the HV battery charging speed?? And it all seems a little convenient that this all started immediately after the service and MOT?
Just looking for any advise or help, as I'm not sure whether I should be demanding a £225 refund for the replaced battery, if something else could have been draining / affecting the 12v and caused all the issues?

 

[HappyGoLucky]

UPDATE: Still waiting for the CCU to be replaced.
Would love to hear from anyone who's had any kind of similar experiences.

 

[Jomarkh]

It's not unusual for a 12V battery to fail but not sure that they die that quickly after a service.
Has the 12v battery only got a year warranty or 3 if it was it's first MOT then it was under 3 years old.

 

[HappyGoLucky]

It's not unusual for a 12V battery to fail but not sure that they die that quickly after a service.
Has the 12v battery only got a year warranty or 3 if it was it's first MOT then it was under 3 years old.

Thanks for your response, my feeling is the same that it's rather unusual for a 12v to go from a "good" to gone in 2 weeks. The car was just under 3 years when it had it's MOT (by a few days!). They told me there is only a years warranty on 12v batteries.

 

[HappyGoLucky]

Thanks for your response, my feeling is the same that it's rather unusual for a 12v to go from a "good" to gone in 2 weeks. The car was just under 3 years when it had it's MOT (by a few days!). They told me there is only a years warranty on 12v batteries.

I guess I'm trying to figure out if something could have gone wrong in any software updates or anything in the service as it seems very coincidental to have these issues straight afterwards. They seem reluctant to tell me any straight answers, which to be fair may be because they don't know, but I can't help but feel the 12v, slow HV charging, and blown fuse in the CCU are not all down to a suddenly dead 12v battery. Don't want to be £225 down if the 12v was a casualty from the issue, not a cause.

 

[Jto]

I guess I'm trying to figure out if something could have gone wrong in any software updates or anything in the service as it seems very coincidental to have these issues straight afterwards. They seem reluctant to tell me any straight answers, which to be fair may be because they don't know, but I can't help but feel the 12v, slow HV charging, and blown fuse in the CCU are not all down to a suddenly dead 12v battery. Don't want to be £225 down if the 12v was a casualty from the issue, not a cause.

Unless you monitor you 12v battery by checking it on the screen or app you will not know if it was charging correctly, 3 years is not bad for a battery coming from China and they do not use a good quality one. Normally when in ready you should see the battery charging at 14v and using the app after a hour standing the voltage should be around 13v could be lower in winter, but you do not want to see it below 12v. I was out today and noticed by battery was charging at 13.5v driving. This could be because in summer you do not use a higher load on the 12v battery like in winter so is nearly fully charge or could be starting to fail so will check the voltage when I next charge the car. One thing the AA man could not put charge in to the 12v battery then it was dead and needed replacing. People are very quick to say it was serviced only a week or so ago and think it was that, they would have not check the condition of the 12v battery a service is mainly check tyres pressure fluid level brake ware suspension steering eg so would have not touch the ccu and if all is fine at the time of the service there is not much then can do and do not have crystal ball to look in to.

 

[Data]

Normally a full car health check takes place at every service. They would normally make sure the 12v battery is charged correctly & that no fault codes are showing. The 12v battery can be the cause of multiple faults when it starts to degrade. If it fails suddenly it can even cause a corruption of the cars telematics software, but that's quite rare.

 

[domwild]

Tesla had a lead acid battery, but they changed that to LiFeP after Brian May could not get his car opened.