MG4 Intelligent battery heating on SE?

[siteguru]

Cabin heating only heats the cabin.

For battery heating, click on the battery tile in the app. On the next page, near the bottom (right above the Start Charging button) there is a Battery Heating slider. Turn that on to start it.

If you click on the "nut" icon at the top right you'll find an option to schedule battery heating.

 

[Astral]

And there I can see now it says: "it is recommended to schedule battery heating 1.5h before using the car". Interesting...

 

[MGFour]

Cabin heating only heats the cabin.

For battery heating, click on the battery tile in the app. On the next page, near the bottom (right above the Start Charging button) there is a Battery Heating slider. Turn that on to start it.

If you click on the "nut" icon at the top right you'll find an option to schedule battery heating.

Oh Course quite obvious where it would be and my brain is functioning as well as an old version of MG4 software. Thank you

 

[Astral]

I'll hopefully do a test later today as my battery is at a lower state of charge right now whilst temps are -1C, I will plug in the OBD dongle and let you know exactly how much draw from the charger etc I read.
Ultimately the BMS will decide what to do.

Great, please do

 

[Kithmo]

Does the car have to be plugged in to the charger to start battery heating from the app ?

 

[Astral]

As far as I know, no.

 

[Kithmo]

As far as I know, no.

I tried switching it on a couple of days ago from the app with the car unplugged and it wouldn't switch on. I know the app was working as I preheated the cabin.
Edit: tried it just now and it works, so it appears just the battery section of the app must have not been working last time.

 

[Astral]

I just successfully started it over the app, the car is parked and locked.

 

[fnegroni]

I tried switching it on a couple of days ago from the app with the car unplugged and it wouldn't switch on. I know the app was working as I preheated the cabin.
Edit: tried it just now and it works, so it appears just the battery section of the app must have not been working last time.

If the battery isn’t cold enough, it won’t.

 

[Astral]

If you start pre-heat from the app, how long will it run? For example the cabin heating will only run for 10min. What about battery heating?

 

[fnegroni]

If you start pre-heat from the app, how long will it run? For example the cabin heating will only run for 10min. What about battery heating?

It will depend on how cold the battery is. I’ve not seen it run for longer than 45 minutes yet. Most times around half an hour or less

 

[Astral]

Yeah I just tested it, outside temp is 8°C and it ran for about 15min. Does it mean it reached 20°C already? Is this the target? I lost about 2% of battery for this.

I have started pre-heating again and got a msg from the app that the battery does not need to be heated. But no idea what the actual temp is.

 

[Anon70]

Did my first battery heating test today. Outside temp was 2 deg C, set the battery to heat form 10am. By 10:45am the battery heating was off and the car had used 3% of it's charge. Strangely enough I seemed to get better miles per kWh on the return trip with no battery heating.

I have never seen the need to heat the battery before (always had good charging speeds) and based on the efficiency figures today will probably never use the battery heating again

 

[fnegroni]

Yeah I just tested it, outside temp is 8c and it ran for about 15min. Does it mean it reached 20c already? Is this the target? I lost about 2% of battery for this.

I have started pre-heating again and got a msg from the app that the battery does not need to be heated. But no idea what the actual temp is.

Yeah target temps are to stop heating the coolant when min and max temps are at or above 17°C.

They might warm up a little more if you wait another 15 minutes or so. But after that it’s likely they’ll stay where they are.

Although for the LFP pack to be at its maximum charge temperature it needs to be at around 34 to 37°C, as long as the battery is above 12°C it starts to charge much faster, and reaches 30°C pretty darn quickly. The regen is also more effective.

In fact, the ‘tipping point’ in the ambient temperature for driving efficiency is around 12°C and 17°C.

 

[Kithmo]

So what about this intelligent battery heating in the car ?
Does it just come on below a certain temperature, is that the intelligent part ?

 

[fnegroni]

Did my first battery heating test today. Outside temp was 2 deg C, set the battery to heat form 10am. By 10:45am the battery heating was off and the car had used 3% of it's charge. Strangely enough I seemed to get better miles per kWh on the return trip with no battery heating.

I have never seen the need to heat the battery before (always had good charging speeds) and based on the efficiency figures today will probably never use the battery heating again

You are missing the point of battery heating then.

Also,, your return trip is likely to be either more or less efficient as one of the two trips will be slightly uphill. Yes, that’s enough to make a noticeable difference.
The tyre temperature also makes a difference, as does the use of the HVAC. On your return trip all of those might have been already warmed up more than on the outward trip. Difficult to tell without all of the data points.

The ‘on demand’ battery heating (intelligent or preheating) is to reduce the battery resistance to be charged/discharged

It affects your regen and maximum acceleration.

What you must also bear in mind it can also protect the battery should you need to charge at much lower temperatures with a granny charger.

 

[fnegroni]

So what about this intelligent battery heating in the car ?
Does it just come on below a certain temperature, is that the intelligent part ?

Yes. It’s intelligent (a bit of a misnomer) compared to the older implementation in the MG5 which was manual.

 

[tsedge]

You are missing the point of battery heating then.

The ‘on demand’ battery heating (intelligent or preheating) is to reduce the battery resistance to be charged/discharged

It affects your regen and maximum acceleration.

It also affects your range.

The increased internal resistance and lower voltages in low temps mean that the battery will start lower and get worked harder to get the same effect - in other words the same driver will need to drive it harder to get the same result, which will result in lower range for the same journey compared to warmer conditions.

This, plus increased use of the cabin heater etc..., is why our batteries give significantly shorter range in winter temperatures.

Therefore it is reasonable to assume that heating the battery would increase the range: after all, that's the difference between summer and winter, isn't it?!

However, on the MG4 it doesn't appear to make much difference to range (or consumption) which does require an explanation.

 

[DixieTGS]

What you must also bear in mind it can also protect the battery should you need to charge at much lower temperatures with a granny charger.

By much lower temperatures are we talking < +5°C or < -10°C maybe? If the former it might just tip the balance towards me getting a charger installed, to keep the charging process simple.

 

[fnegroni]

By much lower temperatures are we talking < +5C or < -10C maybe? If the former it might just tip the balance towards me getting a charger installed, to keep the charging process simple.

I have seen it kick in when above 96% and temperatures hovering around 0 while charging with a granny charger and the battery was cold. It will probably kick in sooner on a 7kW charger but then there’s enough juice to charge and heat the battery