MG5 System Fault - HV Battery Shut Off

[5teep]

There’s the assumption, right in the front.

Drinking all of that pint you bought is poor etiquette too I suppose, if someone wants the seat…

It's etiquette, not law. If you want to sit at a 100kw DC charger pulling 7kw for an extra hour or so it's your business, but, it's wasteful of your time and other people's.

 

[BugEyed]

I like the Portuguese model of the cost being both in terms of charge delivered and time. So if you want to hog a 350kW DC charger to reach a % in the high 90's rather than transferring to AC then you pay for the privilege.

 

[WigglePig]

It's etiquette, not law. If you want to sit at a 100kw DC charger pulling 7kw for an extra hour or so it's your business, but, it's wasteful of your time and other people's.

It’s only wasting the time of others if they are waiting…
And it’s only wasting my time if I’m not drinking some coffee, watching to see if anyone else turns up to use the (one out of three) charger…


Assumptions…

 

[Wakefield5]

I don't think you know what assumption means. Both posts said if somebody is waiting. It is a conditional statement/sentence.

If nobody is waiting then it obviously doesn't matter ?

 

[jackois]

I don't think you know what assumption means. Both posts said if somebody is waiting. It is a conditional statement/sentence.

If nobody is waiting then it obviously doesn't matter ?

Totally agree, If I'm away I charge at a pub charger, 75Kw. I obviously want as much charge as I can get before the journey home. Luckily I can see the car from the pub, but I also keep an eye on the Bonnet app which lets me know the charge is done.

At this point, I always go and move the car as the chargers are visible from the road and I'd hate anyone to drive on because they think the charger is in use...

Incidently, for some reason the car ceased charging at 95%... and the Bonnet app messaged to say it was complete.

 

[WigglePig]

I don't think you know what assumption means. Both posts said if somebody is waiting. It is a conditional statement/sentence.

If nobody is waiting then it obviously doesn't matter ?

Oh, I know full well what assumptions are.

 

[weedavemac]

Where’s the assumption? Charging above 90% on a rapid while people are waiting is poor etiquette.

And to be clear I never said the OP had done this.

How is charging above 90%, on a rapid charger, while others are waiting, poor etiquette?

If it is the only charger, and you need that extra few percent for your journey, then keeping charging is the only option. Nothing wrong with that.

 

[Petriix]

Funnily enough my aim on any rapid charger is to charge as little as possible while being able to complete my journey in the cheapest and most convenient way. I'd have to be on a very unusual journey to require a full charge away from home. Rapid charging is expensive and puts strain on the battery so really is a last resort for me.

The point about etiquette is that charging slows down so much above 90% that it's almost always quicker to move on and charge again later if required. 90% in an MG5 SR is at least 150 miles in most circumstances. You'd have to be on a very strange trip to not be passing another reliable charger within the next 150 miles.

The idea of 'needing' 100% is pretty illogical. I think people are used to filling up their diesel tank and are simply trying to recreate the same thing with batteries, ignoring the massive drop off in power at higher states of charge. You're wasting everyone's time charging at 15kW when you could add the same amount of energy in 1/5 of the time later at 75kW from a lower state of charge.

In my experience, it's unusual for me to be able to drive for more than about 90 minutes before me or one of the kids to need to stop so we tend to add a little charge each time rather than doing a longer charge. We tend to do a tour of Lidl stores because charging is cheap and reliable and we can buy cheap food.

Edit: And of course the dodgy MG charging software makes pushing above 90% a bit of a lottery as to whether you'll even be able to complete your journey...

 

[5teep]

How is charging above 90%, on a rapid charger, while others are waiting, poor etiquette?

If it is the only charger, and you need that extra few percent for your journey, then keeping charging is the only option. Nothing wrong with that.

If you keep drilling down you'll get to China. Of course there's always going to be a situation where you might 'need' that extra power but as Petriix says you are almost certainly going to be quicker moving on to another charger at a later part of your journey where you can top up at the faster rate again.

 

[weedavemac]

If you keep drilling down you'll get to China. Of course there's always going to be a situation where you might 'need' that extra power but as Petriix says you are almost certainly going to be quicker moving on to another charger at a later part of your journey where you can top up at the faster rate again.

That is assuming you can find a reliable, and unoccupied, rapid charger later in your journey. I would always rather charge up than risk moving on and not being able to charge. The network needs to be more reliable, and more plentiful.

I live in Scotland, where numerous 50kwh rapid chargers are free. But not everywhere - different councils have different policies. Being free tends to change people's behaviour. I would rather charge up for free than move on and pay elsewhere.

 

[5teep]

I would rather charge up for free than move on and pay elsewhere.

As said numerous times, it's your choice, as long as you know you would be quicker shifting to a 7kw AC post once you pass 90% charge. 90% gives you even on the coldest winter day ~150 miles and in Scotland there's a rapid charger roughly every 15-20 miles in any direction.

I suspect the days of free charging in Scotland are ending veeeery soon, councils cannot afford to pay the new extortionate rates to let you charge free and will be looking to reclaim from you. Also most council chargers that I visit have max 45 minute charge time with a £5 overstay fee that's added to your Chargeplace Scotland bill.

 

[weedavemac]

As said numerous times, it's your choice, as long as you know you would be quicker shifting to a 7kw AC post once you pass 90% charge. 90% gives you even on the coldest winter day ~150 miles and in Scotland there's a rapid charger roughly every 15-20 miles in any direction.

I suspect the days of free charging in Scotland are ending veeeery soon, councils cannot afford to pay the new extortionate rates to let you charge free and will be looking to reclaim from you. Also most council chargers that I visit have max 45 minute charge time with a £5 overstay fee that's added to your Chargeplace Scotland bill.

There may be one solitary rapid charger every 20 miles in any direction in some areas. But it may be occupied, or it may be not working. I am risk averse, so if I want/need to stay on a working rapid charger I will do so.

There are plenty of CPS chargers that have no overstay fee. Although I recently got caught out in Edinburgh with one that only allowed 30 minutes - not long enough in my book.

Some councils have already started charging. Others are yet to do so. While it is free it is a no brainer to use them.

 

[Petriix]

Yes, the equation is very different with free charging. However, that doesn't protect you from whatever error causes the battery to shut off.

 

[weedavemac]

Yes, the equation is very different with free charging. However, that doesn't protect you from whatever error causes the battery to shut off.

10mm spanner just in case.

The free charging really does change people's behaviour. Tesla drivers avoid their own network to use the humble 50kwh CPS chargers instead.

 

[5teep]

Yes, the equation is very different with free charging. However, that doesn't protect you from whatever error causes the battery to shut off.

There's supposed to be a firmware fix out for this. contact your dealer or wait till you next go in for service.

 

[WigglePig]

I only noticed mine doing this in the fortnight after it was serviced…

 

[james99]

New MG5 registered 19th March 2022 Had 4 HV battery shut Off failures on start-up since 4th October AA recovered car each time to dealers for repair which lasts about 1-2 weeks then failure returns. Now been in Dealers since last failure 13th December for repair again does anybody have idea what the problem is. So far MG UK have instructed dealer to update software but issue not resolved not impressed with reliability of a functioning car.

 

[davebaustin]

Whilst charging on a Public rapid charger the charge stopped at 94% and when I disconnected, the car was showing a system fault; HV battery shut off
After turning everything off and leaving for 5-10 minutes the car came back on,
Has anybody else encountered this and do they think its a safety mechanism protecting the battery?

Same happened to me on my MG5 at Gloucester Services. MG Assist connected me to an AA man who could not diagnose fault but was able to clear it.

 

[joeH]

This exact situation happened to me today. Charged to 94% on a council owned CCS. Charging slowed to 25kwh at 90% (I thought it would slow more than this) at 94%, charging stopped. I tried to start the car and got 'system error'. Took 10 mins before it finally booted up and allowed me to drive. I almost exclusively charge on a slow charger, and regularly to 100%, so my BMS is regularly balanced. Anyway, good to know that this is somewhat common, thought the charger had knackered my car.

 

[jackois]

I had this once, where charging on an Osprey 75Kw charger at a pub having a meal.

I was using Bonnet and it messaged saying the charge was complete. I thought nothing of it, but as we were between courses, I popped out to move the car and make the charger available should someone else need it.

I had no problems unlocking and disconnecting the car and noticed the charge was at 94%. However the car started and moved with no problems. The charge rate averaged out at around 40Kw/hr.