HV Battery Fault

[mgzsdavew]

Hi all, I am receiving this "HV battery fault" on and off for the past week, but with no effect on the car. It seems to have come about when the weather dropped. It stays for a while then disappears. Booked in for January with dealer. Any ideas as to why I am getting it? thanks

 

[Coulomb]

My wild guess: slight electrical leakage at one point in the main battery. There could be a sealing problem, with some moisture getting in.

That won't affect anything immediately, as the high voltage battery is isolated (now with one isolation failure). Though it means that touching certain parts of the HV battery could now be lethal. But that is only of concern to the techs, who should be using high voltage gloves anyway.

The problem is if a second leakage occurs. Then depending on how strong the connections to chassis are, there could be anything from unbalancing the battery to a risk of fire. The risk of fire is very small, usually the leakage is slight. I suspect that if the system detected a heavy leakage, it would not let you drive it at all.

There could be other issues instead, such as an intermittent sensor (voltage, current, or temperature sensor). If so, the only problem may be that the system will be unable to detect future real problems while the sensor is playing up.

Hopefully their diagnostic procedure will find the problem, and that they don't have to hand it over to EV experts. My impression is that some service centres won't open the HV battery if needed, leaving that sort of job to centres that specialise in that work.

I hope I haven't scared you too much. You'll just have to wait and see what they say. Actual serious HV battery faults seem to be extremely rare

 

[mgzsdavew]

Thanks coulomb,

Still no answers. I've had it in a garage in Dublin, but they said they couldn't connect to the car to check the fault because the car is an northern ireland origin car, and connecting can be an issue, which sounds strange. Back in hopefully next week to check, labour costs will apply. Noticed the range has dropped by 70km when fully charged. Hopefully get it sorted soon as I am not keen driving with this fault active.

 

[fred12345]

Thanks coulomb,

Still no answers. I've had it in a garage in Dublin, but they said they couldn't connect to the car to check the fault because the car is an northern ireland origin car, and connecting can be an issue, which sounds strange. Back in hopefully next week to check, labour costs will apply. Noticed the range has dropped by 70km when fully charged. Hopefully get it sorted soon as I am not keen driving with this fault active.

There should be no labour charge if the car is under warranty! Check that with MG and another MG authorised garage first. Also, argument that the car is NI sourced and there might be connection difficulties (which I guess disappear on payment of labour costs???) sounds equally rubbish - they are all Chinese, no?

Check all this with MG customer services and another MG garage (even in NI if you have to) before they make you pay ...

 

[mgzsdavew]

Thanks for your reply Car is 211 2021 with 53k km. They said it could be outside the warranty (36 months) if it's a component related to the HV batteries and not the HV cells themselves. Will have to look into it.

 

[Coulomb]

Car is 211 with 53k.

Can you explain that please? I don't know if 53k is in pounds or euros or miles or kilometres. 211 is a complete mystery to me, possibly because I'm in Australia.

They said it's could be outside the warranty (36 months) if it's a component related to the HV batteries and not the HV cells themselves.

Wow, that's sneaky. Anything inside the HV battery module is going to cost a lot and possibly require specialist technicians, and the whole thing is supposed to be sealed. So that exclusion from the seven year warranty is quite shocking to me.

The seven year warranty is supposed to put buyers' minds at ease; with the many exclusions, it seems to me that it won't be doing that if people get the impression that the warranty is worthless half the time. Especially where it relates to expensive parts like those inside the HV battery module.

 

[Tim Green]

Yes, they should not really be able to use the "7 Year warranty" tag with so many exceptions. It downgrades the marque.

 

[hmadsen]

Saw a video of someone changing the HV contactors on a Leaf, the contactors had welded themselves, so they could not disengage.

This was supposedly a common issue.

The repair was to lift the car, disconnect the complete batterypack, unbolt it from the car, lower it, take it out, undo all the bolts holding the "lid" in place, cutting the seal, removing the lid and then replace the contactors.

To be honest, such a thing as the contactors, should either be placed outside of the battery in an accessible position or be mounted in such a way that it could be removed from the batterypack without removing it.

This kind of design where a component you "know" will fail, is put inside the sealed battery, is just plain and simply moronic.

 

[mgzsdavew]

Can you explain that please? I don't know if 53k is in pounds or euros or miles or kilometres. 211 is a complete mystery to me, possibly because I'm in Australia.


Wow, that's sneaky. Anything inside the HV battery module is going to cost a lot and possibly require specialist technicians, and the whole thing is supposed to be sealed. So that exclusion from the seven year warranty is quite shocking to me.

The seven year warranty is supposed to put buyers' minds at ease; with the many exclusions, it seems to me that it won't be doing that if people get the impression that the warranty is worthless half the time. Especially where it relates to expensive parts like those inside the HV battery module.

Apologies, forgot this is a worldwide group. 53000km and the car was registered is 2021. Yes, it be interesting to see what they find. I'm still waiting on a date to book it in.