EV mode keeps dropping out on MG HS PHEV

[Hage52]

I live just over a mile from my workplace and I have found that on my journey, the car gets to around 0.75 miles then drops out of EV mode and when I try to put it back, I get the message 'EV mode not supported'. I haven't got lights/AC/heater on, but still it happens!

Make sure that the AC heater is off and try again. what i also do when it is cold outside is drive with heater on for 3 km and heat the car realy hot. then i do the ac off or i put it on 1 and set the temp to 16 degrees. and then i have no problems with the ev mode. please try this and play with it.

 

[Cafeg]

I have a 3 month old MgHs phev. yes that all works. I just took it out of auto in heating, dropped it down to 16, (temp outside was 11 here inNZ) and the fans around 2 so they aren't blowing hard. Start it in EV mode and drive around without it switching out of EV mode. It used to start the engine when I started the car before and keep the engine on for 2 to 3 Kms. I also found that when it started switching out of EV mode, I could get it back into EV mode by taking my foot off the throttle the pushing EV mode.
Be good for the summer as the aircon doesnt seem to affect it.
So It must be using the car water temp for the heater as it has no heat pump ?
Thats a bad bug, its a wonder they dont fix it and put a heat pump in like toyota Pruis have.
Like others I didnt find this until after a few months and tried to see what I could do about it.
If the Phev battery is fully charged why cant it heat from the battery instead of starting the petrol motor ??
The car is great apart fromthat annoying bug. I really enjoy driving it

what i do most of the time now is driving for a few km heating the temperture at 24 degrees so the car is very warm, then turn it down to 1 and set it to 16 degrees....on the window and feet....and then you have no problem putting it in ev mode....i also tuns on the heating seats so it is good to drive in cold weather...so most of the time i drive about 3-4 km and then i drive 60 km in ev mode.
keep experimenting with this and you see that it is possible....i also tried the windsceen blow mode and put it to 1, it also works sometimes. or just put the blower on 1 in cold mode

Air con will demist your windscreen faster than heat anyway

 

[Lovemyev]

Like others I didnt find this until after a few months and tried to see what I could do about it.
If the Phev battery is fully charged why cant it heat from the battery instead of starting the petrol motor ??
The car is great apart fromthat annoying bug. I really enjoy driving it

I don’t own a HS PHEV but the engine jumping into life, when heat is requested is a crazy system.
Before going full EV in 2019 we had a VW Golf PHEV.
It had a much better refined system than the HS PHEV.
In effect, it had a very clever split heater element.
You could heat the cabin by using the traction battery individually if you wanted.
Also, you could drive purely on electric power up to 80Mph with out any intervention from the ICE if you wished to do so.
When hybrid mode was selected, the ICE would start ( if required ) and then as the water was heated, a thermostatic valve in the system would open and allow heated water to heat the cabin and therefore save on EV range.
It was a seamless process that worked in combination with a very slick DSG gearbox.
A brilliant piece of engineering IMO.

 

[Kerno]

VW Golf PHEV is 40k at that price they can afford to put in an electric heater. The HS can also drive at up to 80mph without the ICE. It is a bit of an oversight not having an electric heater but these cars are built to a price, something has to go.

 

[Cafeg]

Once the HS gets warmed up its fine, its just that initial startup and drive for 3 or 4 km with the cabin being heated. Now that I know it is doing that, I'll try cutting the temp down for a startoff and turning Auto off. Once it gets going for a few k's its fine. I must admit I turned the heater off and cut the temp and fan down and went for a drive this afternoon and in straight EV mode from starting to coming back it was very different !! Its certainly a shame though as everything else is great.

 

[Kerno]

Oddly though it runs the aircon OK in electric-only mode. I have only had mine for a week and it always stayed in EV mode when put in. The weather has been lovely though so no heat is required. Running the aircon doesnt seem to have much affect on range either.

 

[Cafeg]

I tried this today - Had to go to the shopping centre 12km away. Left HVAC on auto and dropped the fan down from medium to low in the HVAC settings. Left the outside vent to recirculate air in car. Set the driver and passenger temp to 19deg, they were both on 22 deg before. Outside temp car was saying was 15deg. Started the car and pushed EV button and it stayed on. Drove all the way on EV, normally would have to do about 3km before it stayed on. Plugged it in to free charging at shopping centre and went shopping. Came back and car started in EV mode. Left driver/passenger setting on 19 deg. Stayed in EV mode all the way back, outside temp was still 15deg. I put it on recirculate air in car as I figured body heat would take the inside temp of car up as well In summer it will be ok as aircon doesnt affect it by the look of it. Was a lot better drive instead of pushing that EV button all the time

I also asked MG help and this is what they said :

we’ve heard back from our technical team and they’ve mentioned there are several factors that may affect this:- Low voltage electrical load – a greater demand in low voltage electrical consumers (Cabin Heating, Interior fan, Infotainment use, Auto Headlamps, etc.) will also result in the EV only mode not functioning as the combustion engine is required to drive the Alternator. - Ambient (Outside) temperature also plays a part and the vehicle will take advantage of downhill “runs” to actively regenerate the HV battery by deliberately switching on the ICE – this also provides (additional) engine braking. - The TCM can also control “Auto” mode depending on the current and desired transmission ratio.

Ahh, I think I get it now, by the low voltage load they mean the 12 volt battery system so when that is low or under load they have to start the engine to run the alternator to charge the 12 volt system.
Its a pity they cant do that off the big battery. I wonder how full EVs get on then ? they must run of the car EV battery ? Actually my 2010 prius has 2 batterys in it, A 12 volt one and a small ev battery which I wouldnt notice it in the as the engine is always cutting in on that. That only goes 2 or 3 kms in EV mode and only at 50km an hr.

I didnt realise that even a tesla has 2 batteries and a 12 volt system..
Does charging an EV charge the 12V battery?
But apparently they still need that 12v battery to start...
How is it charged? Since there isn't a mechanically rotating pulley system under the hood like a traditional ICE vehicle, an alternator doesn't work to recharge the 12-volt battery. Rather, electric cars use a converter that draws current from the large battery pack, topping it up.

 

[Lovemyev]

I didnt realise that even a tesla has 2 batteries and a 12 volt system..
Does charging an EV charge the 12V battery?
But apparently they still need that 12v battery to start...
How is it charged? Since there isn't a mechanically rotating pulley system under the hood like a traditional ICE vehicle, an alternator doesn't work to recharge the 12-volt battery. Rather, electric cars use a converter that draws current from the large battery pack, topping it up.

EV’s need a 12 volt battery to power all of the 12 volt systems in the car.
In this respect they are no different from an ICE car.
The 12 volt battery receives its charge in a few ways, it will be charged when the car is collecting a charge, plus when the car is in ready mode, it receives a charge from the inverter / main traction battery usually located under the car.
It’s a voltage of around 14 volts which is similar to the voltage provided by the alternator on a ICE car.
All of the 12 volt system on an EV need that old fashioned 12 volt battery to run all of the modules / lights / heater blower etc etc.
The cabin heater element requires a lot of power, so this draws its power from the inverter / traction battery.
Hope this answers your question.

 

[ACatt]

@Matty regarding 1, I have replicated this issue multiple times. If you are down downhill for a while the car exits EV mode. My initial guess was something to do with increase of speed while going downhill causing it to exit but since then I have managed reproduce it while actively braking through out downhill part and the car still exiting.

The slop of downhill path didn't make a significant different too. My current theory is that there is a max regen value and if that is breached, the car exits. Once it exits, it takes a few tries to get it back in EV mode

Downhill exit relates to vacuum assistance for braking. The electric vacuum pump overheats and has to bring on the ICE to maintain vacuum assist for braking. MG need to reprogram so that if you select EV it is the default when parameters for EV are met. instead default is Auto ICE with manual selection of EV. Not impressed.

 

[midician]

Downhill also charges your battery and if it’s too much charge or the battery is full , regen switches off and the car defaults to the ICE to slow you down .

 

[TrevH]

Hi had my PHEV TROPHY for 5 months 3300 miles and for some reason it no longer recharged the battery on a journey? I thought that braking and deceleration re charged a little but had nothing for some time now . Any ideas?

 

[Cafeg]

Hi had my PHEV TROPHY for 5 months 3300 miles and for some reason it no longer recharged the battery on a journey? I thought that breaking and deceleration re charged a little but had nothing for some time now . Any ideas?

I read that it doesnt do that if you have cruise control on for some reason. Do you have it on for your journey ?

 

[TrevH]

I read that it doesnt do that if you have cruise control on for some reason. Do you have it on for your journey ?

No not since I read that to.

 

[midician]

Is your recharge set to high low or auto ? On long trips mine pretty much drains the battery to zero when set to auto .

 

[TrevH]

Is your recharge set to high low or auto ? On long trips mine pretty much drains the battery to zero when set to auto .

I leave it on auto as someone on here said that on high it uses more petrol on long journeys. I still can't figure out just what these settings are useful for?

 

[Kerno]

If you use any mode other than auto the car tries to keep the charge at 50% for med and 100% for high, but it will use a lot of petrol to do this so it is not recommended. I used it once as I wanted battery power for driving around Bowness in the lakes as I depleted the battery on the trip to get there. It does work very well but a very expensive way to charge the battery.

 

[ronmaz]

I thought that braking and deceleration re charged a little but had nothing for some time now . Any ideas?

Braking, i.e. putting your foot on the brake pedal does not in itself recharge the battery, in fact it would decrease the amount of charge going back to the battery because you are manually slowing the car down using the brake pads rather than allowing the car to decelerate on its own.

Deceleration, i.e. coasting without touching the brake pedal, will add a small amount back to the battery but the amount is tiny. The faster your speed when you start coasting will add more charge back to the battery but you're not going to see the battery % shoot up by doing this. When coasting, you'll see the power gauge on the car will go into the negative. The higher the negative number, the faster the charge is going back into the battery. Coasting for 20 seconds might see your battery charge increase by 1% at most but then coasting for that amount of time would slow the car right down and you'd have to accelerate again which would just take that charge right out the battery again.

Driving use the ICE in auto mode on a long trip will also slowly add charge back to the battery, but slowly is the word. In my experience, driving for an hour at freeway speeds my battery percentage might go up by 3 or 4%, but less if it's a hilly road because even using the ICE, the car will use the electric motors for assistance when going up hills so you'd be using battery power for that.

 

[TrevH]

Thanks for the info

Braking, i.e. putting your foot on the brake pedal does not in itself recharge the battery, in fact it would decrease the amount of charge going back to the battery because you are manually slowing the car down using the brake pads rather than allowing the car to decelerate on its own.

Deceleration, i.e. coasting without touching the brake pedal, will add a small amount back to the battery but the amount is tiny. The faster your speed when you start coasting will add more charge back to the battery but you're not going to see the battery % shoot up by doing this. When coasting, you'll see the power gauge on the car will go into the negative. The higher the negative number, the faster the charge is going back into the battery. Coasting for 20 seconds might see your battery charge increase by 1% at most but then coasting for that amount of time would slow the car right down and you'd have to accelerate again which would just take that charge right out the battery again.

Driving use the ICE in auto mode on a long trip will also slowly add charge back to the battery, but slowly is the word. In my experience, driving for an hour at freeway speeds my battery percentage might go up by 3 or 4%, but less if it's a hilly road because even using the ICE, the car will use the electric motors for assistance when going up hills so you'd be using battery power for that.

very interesting, many thanks for the valuable info

 

[Cafeg]

B

Driving use the ICE in auto mode on a long trip will also slowly add charge back to the battery, but slowly is the word. In my experience, driving for an hour at freeway speeds my battery percentage might go up by 3 or 4%, but less if it's a hilly road because even using the ICE, the car will use the electric motors for assistance when going up hills so you'd be using battery power for that.

I think I have seen that when driving in auto mode. up the top of the display there is a seperate line that starts up going direct from the ICE to the battery that is different from the charge/discharge line at the bottom. and a different color. I meant to try and take a photo of it but always driving so cant Has anyone else seen that ?

 

[sky0000547]

Hi had my PHEV TROPHY for 5 months 3300 miles and for some reason it no longer recharged the battery on a journey? I thought that braking and deceleration re charged a little but had nothing for some time now . Any ideas?

When your power meter on your dash showing negative percentage whilst you are off the pedal/decelerating, it is charging the battery. In order for you to see any major gains in the battery, you will need a very long hill to come down. I find that braking doesn't really add much if at all to the regen.

Let's just say when you are off the pedal and regen braking comes in, it is maintaining your battery charge so you are basically travelling for free. With any luck on a hill it might add 1% to your battery.