Understanding the Battery Heater logic on the MG ZS EV LR (2023)

[D4niso]

Hello everyone,

I’ve owned my MG ZS EV Long Range (2023) for a year now, covering about 40,000 km. Recently, I’ve run into a bit of a challenge regarding DC fast charging speeds and the battery heater.

From what I’ve observed, the battery heater only seems to kick in when the battery temperature is below 10°C. If the battery is at 11°C, it stays off. This becomes an issue during winter here in Portugal; while it’s not freezing, the battery often stays just warm enough to disable the heater, but too cold to accept a fast charge.

When driving at lower speeds on country roads, the battery doesn't naturally heat up enough. This results in charging speeds of only 30-50 kW. What should be a quick 7-minute stop often ends up taking double the time.

My questions for the community:

Does anyone have technical documentation or specific insight into the exact logic of this system?

Is there any way (via settings or OBD2 tools) to manually trigger the battery pre-heating?

Are there any "tricks" or driving styles you use to raise the battery temperature before hitting a charger in mild climates?

Looking forward to your insights!

 

[fred12345]

Not what you want to hear but: I would not worry about it too much. I'm not technical enough to go into battery chemistry, temperature and charging speeds but from experience, there is more to it than the temperature - I managed to charge quite fast in winter and quite slow in summer ... It depends on the charger as well as the battery charge level, it slows down fuller the battery is .. Sure way to heat up the battery is to drive sporty and fast but that defeats the purpose, you'll just use up more energy that will keep you charging for longer ...
You can try turning the battery heating on an hour earlier from your iSmart app and see if it makes any difference but as I said, I wouldn't worry about it too much ...

 

[Data]

Battery heaters are not needed or effective unless at 10c or below & really have little effect until near or below freezing. If you car was not charging above 30-50kw it will normally be for other reasons, not temperature unless at or near freezing. As Fred says it depends on state of charge & how powerful the charger you are using actually is. Was someone else using the same charger as you (dual bay shared charger)? That will reduce the charge speed by half. The only time my Long Range ZS has reached maximum charge speed of 94kw's was on a long road trip in the summer with a SOC at 30% & an ambient temp of 25 degrees. The charger was a 180kw DC charger. Most of the time it tops out at 50-60kw at 55-60% soc at around 16 degrees. But it's so variable & can be higher or lower. Don't worry about it. There are no tricks to alter this.

 

[MickeySw]

Does anyone have technical documentation or specific insight into the exact logic of this system?

Assuming it’s the same system as in the MG5 then you’re right, the manual heater won’t start unless the battery temperature is below 10deg.

While driving the battery is keep at roughly 10deg or ambient, whichever is higher.

Even if you manage to get the heater to start, it just turns off once it reaches it’s set temperature, I.e. the battery cools down quickly afterwards, to time this right is near impossible without OBD temperature data.

Is there any way (via settings or OBD2 tools) to manually trigger the battery pre-heating?

Not that I’m aware of..

Are there any "tricks" or driving styles you use to raise the battery temperature before hitting a charger in mild climates?

Our colleges in Germany can ‘floor’ the accelerator for the last 15min before plugging in, seemingly it does have a benefit on multiple stop, long range journeys.

As already mentioned the only other way to heat up the cells is repeated, hard acceleration followed by brisk Kers3 braking, but that may only give you whiplash and unwanted attention from law enforcement?

It’s also thought that this only ‘works’ for NMC batteries..

 

[D4niso]

’ve experienced this after driving at least 350 km on country roads at speeds between 40 and 90 km/h. Because of the low speed, the battery temperature did not even reach 15°C, and my state of charge was around 20–30%. I was expecting charging speeds close to 80 kW, but when I arrived at a 150 kW charger, it started at 45 kW and only gradually increased to 55 kW after some time.

Still, if there is nothing I can do to override this system, then we simply have to accept it. It’s a very frustrating system.

IF the system was able to heat up to 22ºc I would charge in 5 to 7 mins and then go home with charge .

 

[Data]

In summer it'll be much faster. You'll see. But short chargers of just a few minutes never usually reach a fast charge. Even in summer a short charge won't go at maximum speed usually. 5-7 mins indicates you aren't going to put in much. A longer charge will go much faster (reach higher speeds).

 

[Data]

Posted in error

 

[D4niso]

That I know, but i do have to travel in every season. Leaving me to take more time in the winter...
There is a manual override inveted by someone for other brands.
Is there anything like it on MG ?

 

[Data]

Not on the ZS.

 

[D4niso]

Not on the ZS.

What other model has this ?

 

[MickeySw]

What other model has this ?

Iirc some MG4’s can pre-heat the battery to increase CCS charge speeds if you select a charger on the built-in SatNav?

 

[Data]

Many MG4's have intelligent battery heating.

 

[Data]

Most of us don't usually just stop to charge. We stop to do other things but plug in for a top up. That way you don't waste time.

 

[D4niso]

Many MG4's have intelligent battery heating.

ZS EV has inteligent battery heating.
But it only works if the battery is below 10c

 

[Data]

ZS EV has inteligent battery heating.
But it only works if the battery is below 10c

It's not intelligent like the MG4. It's very basic.
Edit: D4niso, it might be more intelligent than I thought. Just realised it's more similar to the MG4 than I thought on the later models like mine. Mine is 2024 model.