Charging Problem

[Merry]

How much charge did your get in being on a rapid for an hour?

Went from 13 to 85%. I did spend a little while faffing getting the bonnet app working too, I actually connected and disconnected it twice in the process of doing that.

50kw charger, charging between about 38kw at the start and 44kw before it tailed off after 80%. Something like that anyway.

 

[Lovemyev]

Could be an issue going into that mode while the car is initiating the charge though. I don't fancy trying that.

I agree.
The post from @Lambo51 reference the manual, appears to support the theory that before starting a rapid charge, the car should be completely powered down, then wait 10 seconds before starting to rapid start ( HV battery contactors to disconnect I guess ).
Then, when the rapid charge is underway, then you can power up the car into the "ON" condition to see SOC and run the 12 volts items.
Is "ON" what will we know as the STANDBY situation ?.
It does not say "READY" status ?.
As we know, the 12 volt battery is also being charged when the car is receiving a charge from a wall box or rapid unit.

 

[Merry]

Well I meant on as in once it was charging I put my foot on the brake and turned the HV system on for heating and such.

That's what I wouldn't attempt while initialising a charge.

 

[N2STY]

OK I have a little Theory
please forgive my dyslexia
We know the fault happens at DC charging now are we 100% sure the 12v battery chargers when on DC charger? we know it chargers the 12v battery on AC charging because of the on board AC charger on the car but for DC you are charging the HV battery bypassing on-board charger direct to the battery
Now when DC charging people use radio and screen on the car with out ready mode if 12v is not charging you are draining the 12v battery then after charging you try and get ready mode but not enough currant/voltage in 12v to power the solenoid to activate HV battery then you get the fault
I hope someone will understand what I am trying to say as the most common fixes are replacing the 12v battery till it get low again?

 

[N2STY]

This is why disconnecting the battery is not fixing the problem as battery is already to weak but if the aa disconnect the and use jump leads on battery say 5 mins then reconnect the battery may stand a chance of getting the solenoid for HV to work I imagine this would really help? Worth a try if your in that situation nothing to lose?

 

[Lovemyev]

This is why disconnecting the battery is not fixing the problem as battery is already to weak but if the aa disconnect the and use jump leads on battery say 5 mins then reconnect the battery may stand a chance of getting the solenoid for HV to work I imagine this would really help? Worth a try if your in that situation nothing to lose?

Maybe another good reason to carry a "Jump Pack"in your car ?.
I always carry one with me !.

 

[Merry]

I guess all you'd need to do is pop a meter on the battery while it's dc charging to work that one out.

 

[N2STY]

I would also say people disconnecting the 12v battery you need to drain the capacitors of residual current easiest way I can think of is after disconnecting is hold horn down a few seconds and maybe use hazard light swith should drain capacitors to reset ecu I have had this work on a few car when just battery disconnect didn't work that's my 2p worth

 

[Kithmo]

I guess all you'd need to do is pop a meter on the battery while it's dc charging to work that one out.

Wouldn't the 12v meter in the car show it (does the gen 2 have one) ?

I would also say people disconnecting the 12v battery you need to drain the capacitors of residual current easiest way I can think of is after disconnecting is hold horn down a few seconds and maybe use hazard light swith should drain capacitors to reset ecu I have had this work on a few car when just battery disconnect didn't work that's my 2p worth

ISTR someone saying take both leads off the battery and join them together does this.

 

[Coulomb]

are we 100% sure the 12v battery chargers when on DC charger?

I can't see why the DC-DC would not come on every time the contactors are closed. They have to close to charge the battery (AC or DC), otherwise, the battery is isolated for safety. You can't charge an isolated battery.

So I'M 100% sure in my own mind, even though I've not put a multimeter on it, and don't own a 2022 model.

Edit: And yes, you probably can tell from the crude auxiliary "voltmeter" on the dash. Presumably the facelift models have a similar, or hopefully higher resolution, voltmeter.

 

[N2STY]

I can't see why the DC-DC would not come on every time the contactors are closed. They have to close to charge the battery (AC or DC), otherwise, the battery is isolated for safety. You can't charge an isolated battery.

So I'M 100% sure in my own mind, even though I've not put a multimeter on it, and don't own a 2022 model.

Edit: And yes, you probably can tell from the crude auxiliary "voltmeter" on the dash. Presumably the facelift models have a similar, or hopefully higher resolution, voltmeter.

I do agree but something is happening and in my mind it could be something like this even if like you said in one of your recent post the leaf had a low charge problem this could be the same where the draw is higher than the charger?

 

[Coulomb]

you said in one of your recent post the leaf had a low charge problem this could be the same where the draw is higher than the charger?

It's unlikely. The DC-DC is quite powerful, certainly 80 A, possibly a lot more. The output of the DC-DC seems to be regulated by auxiliary battery voltage, like "whatever current it takes to get that battery to 14.0 V".

If the MG has a chronic undercharging problem like the early Leafs, then yes there could be weird problems, but why does it seem to be linked to DC rapid charging?

I suppose if there is a bug or glitch in the circuitry and/or firmware such that the auxiliary battery doesn't get charged during DC rapid charging, then that would explain it. DC charging often lasts the best part of an hour or more, and the auxiliary battery would be powering many ECUs, pumps, and whatever entertainment the owner is using for that period of time. I think it's more likely that some unforeseen combination of events during DC rapid charging confuses and/or crashes one of the ECUs, and it writes crazy fault codes or otherwise causes havoc, perhaps spraying the CAN buses with traffic, confusing other ECUs. Maybe it crashes in such a way that it overwrites part of its own firmware; that would explain why disconnecting the battery doesn't fix the problem.

Wild thought: maybe the bug/crash causes the DC-DC to discharge the auxiliary battery instead of charging it. The discharged energy could end up in the main battery and not be noticed much, and/or get wasted as heat. Then the auxiliary battery is the "memory" that causes problems with the next start-up, and of course disconnecting the auxiliary battery doesn't help.

Edit: on further reflection, it's probably just that the charging firmware sets a very serious fault code, which is what prevents the car from starting from then on until the code is cleared.

 

[Ozzie1989]

Wouldn't the 12v meter in the car show it (does the gen 2 have one) ?

ISTR someone saying take both leads off the battery and join them together does this.

Yes that's correct, join the positive and negative leads together once both are disconnected from the battery. This will drain any capacitors etc.

Do not join the positive and negative terminals of the battery together or something all together more exciting will happen.

 

[Dave53]

Can't speak for the ZS but I thought it may be worth mentioning that on the MG5 it is recommended to put the vehicle into ready mode whilst rapid charging if you want to use the heater or air conditioning etc.

Even though in ready mode, the vehicle won't let you drive it as the charger is connected so no issues there.

Now I'd have thought that MG would have still allowed this on the ZS, to be honest, so am interested to see if that's the case ?

The car won't allow you to go into the ready mode when a power point is connected, even if you press on the brake for obvious reasons, the old ZS has 3 modes as will the new one I would imagine but not sure, 1st press 12v system, second press HV system stops 12v draining, next option press the brake pedal and press the start button it then goes into full ready mode and in the old EV the word READY appears on the dash, this is the only time the car will allow you to move, if the new ZS is having the same problem as the old one had(mine included) where a rapid charger had a malfunction when it was plunged, the car went into shut down to protect the HV system, they put a fix on my car to stop it going into the full shut down under these (I can't understand why this has not been corrected in the new model) circumstances as to when that happens it needs to go to a dealer who then needs to hook it up to the MG computer system to erase the code that stops the car powering up ( this was stated by the Main Dealer), at the time it happened to me it was a tow to the main dealer, I have had no problems since the initial problem, it is not the car that instigates the problem it's the power point that is the issue, the problem with the MG is the way it was handling the issu it was too severe, but then again I was thinking if it did not have a robust protection system and the cars HV system was damaged by a power point who would be responsible, its quite a conundrum in my opinion and could end up in a battle as to who was ultimately responsible for any repairs, I'm surprised there is not an insurance product specifically to deal with possible Power Point damage.

 

[hmadsen]

Edit: And yes, you probably can tell from the crude auxiliary "voltmeter" on the dash. Presumably the facelift models have a similar, or hopefully higher resolution, voltmeter.

There is no "voltmeter" like on the original ZS EV that i could find.

There is an indicated voltage in one of the 4 menu's in the instrument cluster screen though, but it is not like on the old one, where it is an indicator of how charged the battery is, but more a "This is the current voltage" (Well, maybe the 4 bars under the battery is actually an indicator, but this menu is not the default when starting the car, so you have to flip through menu's to get to this screen)

See picture.

 

[Vipar]

Went from 13 to 85%. I did spend a little while faffing getting the bonnet app working too, I actually connected and disconnected it twice in the process of doing that.

50kw charger, charging between about 38kw at the start and 44kw before it tailed off after 80%. Something like that anyway.

How much did that cost you and what was the charge rate?

 

[Merry]

How much did that cost you and what was the charge rate?

38 - 44kw. It was free because of my bonnet promo codes, but would have been £20 at the fastned rate.

 

[Pauly]

The app gives you the 12v battery voltage, i have noticed mine rise to 14+ when connected to granny so just need to check the app when connected to DC supply

 

[Pauly]

Mine is currently on charge in the garage via granny and you can see the 12v batt at the bottom

 

[N2STY]

The only thing is when you use the app does it wake the car up so may not be the right Reading but definitely interested to see the results