Car battery (parking in the sun)

[fatih]

Hello, does leaving the car under the sun pose a risk to the battery?

 

[Flightengineer]

My car parked under open sun almost every day. In Israel its above 30 and close to 40 celsius every day. No issues so far...

 

[Coulomb]

does leaving the car under the sun pose a risk to the battery?

Parking in the sun will increase the average temperature of everything in the car, including the traction battery. It's a fact that the higher the temperature, the higher the degradation, in any battery.

No issues so far...

It's a gradual thing. You're not likely to notice anything drastic right away.

If you have the choice, choose shade. If you don't have that choice, then there's nothing you can do about it.

 

[tsedge]

Hello, does leaving the car under the sun pose a risk to the battery?

In a word: "no".

You need not treat your EV any differently than an ICE car.

Personally I try to chose shade if I can, because sunlight makes the car hot and ages interior materials. But never because of the battery.

 

[turntoport]

per tsedge.
Perhaps also try to remind yourself (o.k, difficult on a very hot day) that (i) if 'soaked' (i.e. exposed for a long enough period at whatever temperature a thermometer might read) the battery will eventually reach that ambient temperature - if it's in the 45+ deg C region all current (sorry) Lion battery chemisteries won't like it too much, and suffer a slightly increased 'ageing' rate. So after a day of hotness your battery might be a bit susceptible in the late afternoon, for example. What to do? Try not to drive away with large boots of juice - the heavy current draw won't be good for a 'hot' battery-pack. (ii) similarly, don't charge at absolute max rate if avoidable (but max throttle driving is worse). (iii) 'Hot' days feel hotter to you because your body doesn't like being in a medium (limited to air or water, hopefully) above 37 deg C - not for long, anyway. If there's any wind/'breeze', though, your body discomfort due to 'forced convection' (i.e. wind, airflow) heating is dramatically increased. (This effect is the opposite of 'wind-chill' - to you the cold/heat feels much worse than the difference actually is. The car doesn't have this problem, as it doesn't lose fluid/get frostbite/have it's nuts drop off when it gets warm/cool. (iv) The car bms will most likely manage charging/current draw quite well, so it's doubtful you could do much harm anyway. (v) sunshine doesn't cause sunburn on batteries.
Should be fine, but parking in the shade (per several suggestions above) is a smart move if possible.

 

[Bam Bam]

The battery is in the bottom of the car so it isn't in direct sunlight.

Perhaps the surrounding tarmac could be heated by the sun and that will radiate up into the battery. Or the cabin heated up and that will radiate down.

But generally I wouldn't have thought the battery will get as hot sitting in the sun as it will be when you put your foot down on the accelerator.

Or was the point @Coulomb making that the BMS doesn't control the temperature when the car is sitting but it does when the car is parked?

 

[tsedge]

A few other relevant points:

• The battery has a huge thermal mass, so takes a long time to heat up anyway.
• Depending on the chemistry batteries like to be operating in the 20-40°C range as optimum for range and rapid charge speed.
• EVs can be designed to monitor battery temperature when parked and run the coolant loop for the battery to keep temperatures under control.

I don't know what the MG4 does in these scenarios.

But I do know that we have had vehicles without ANY form of thermal management for 15 years now (e.g. Nissan Leaf) and there's no major issue at all, only degradation showing up after many years and miles.

I'd be much more worried about the flashpoints of chemical fuels in a direct sunlight situation.

 

[OriginalBigAl]

A few weeks ago it was 35°C here. Mine was parked all day in the sun and when I got in it was sweltering. Of course I turned up the the A/C to max but was disappointed with the results, so I posed the question here about the cooling efficiencies, most replies were that it was favourable so I was almost under the assumption mine was faulty. Using it since after parking in the shade its been fine. Upon reading the maintenance manual it does say that the battery cooling system shares the A/C refrigerant with the cars internal cooling system and where both are required at the same time the battery takes precedence so the internal A/C output will be diminished until the battery has reached a lower temperature. Something to bear in mind when it's hot.

 

[Coulomb]

Depending on the chemistry batteries like to be operating in the 20-40°C range as optimum for range and rapid charge speed.

True. But extra degradation comes with the better performance.

EVs can be designed to monitor battery temperature when parked and run the coolant loop for the battery to keep temperatures under control.

Also true. But my impression is that few EVs actually do this. I think Teslas do, at least under extreme conditions, and perhaps a few high end German EVs. I'm pretty sure that no MGs do this.

 

[Wil Tryharder]

One of these might take the pressure off your AC on sunny days. Quite simply the best sunshade I’ve ever owned ? made to fit by SnapShades. I’m sure there are others much better than the $ shop ones.

 

[Buster72]

Hello, does leaving the car under the sun pose a risk to the battery?

What is the alternative during the summer?

 

[Buster72]

A few weeks ago it was 35°C here. Mine was parked all day in the sun and when I got in it was sweltering. Of course I turned up the the A/C to max but was disappointed with the results, so I posed the question here about the cooling efficiencies, most replies were that it was favourable so I was almost under the assumption mine was faulty. Using it since after parking in the shade its been fine. Upon reading the maintenance manual it does say that the battery cooling system shares the A/C refrigerant with the cars internal cooling system and where both are required at the same time the battery takes precedence so the internal A/C output will be diminished until the battery has reached a lower temperature. Something to bear in mind when it's hot.

In my experience, you have to have the fan on maximum and even then the AC is not brilliant.

 

[JonnyG]

I'd be more worried about Fast DC charging in hot temperatures as the battery can get over 40°C in these circumstances.

 

[fnegroni]

As I have an OBD2 dongle I could have read the battery temperature over the last few days but I forgot ??‍

 

[Ian Key]

One of these might take the pressure off your AC on sunny days. Quite simply the best sunshade I’ve ever owned ? made to fit by SnapShades. I’m sure there are others much better than the $ shop ones.
View attachment 27643 View attachment 27644

They do make a difference. I got an umbrella type MG4 specific one from AliExpress.

Don't ask for a link as since MG cracked down on unauthorised MG badged products they are no longer available.

 

[Tr380r67]

We have two Men Gf 4 Trophy LRs and had no issues.

 

[Archev]

A few other relevant points:

• The battery has a huge thermal mass, so takes a long time to heat up anyway.
• Depending on the chemistry batteries like to be operating in the 20-40°C range as optimum for range and rapid charge speed.
• EVs can be designed to monitor battery temperature when parked and run the coolant loop for the battery to keep temperatures under control.

I don't know what the MG4 does in these scenarios.

But I do know that we have had vehicles without ANY form of thermal management for 15 years now (e.g. Nissan Leaf) and there's no major issue at all, only degradation showing up after many years and miles.

I'd be much more worried about the flashpoints of chemical fuels in a direct sunlight situation.

Taps nose with side of forefinger ?

 

[DrPlokta]

We have two Men Gf 4 Trophy LRs and had no issues.

How do you know you’ve had no issues? If high temperatures are causing the battery to degrade faster you won’t see any effect now, you’ll see it after ten years and 200,000 miles when your SOH is 80% instead of 85%.

 

[Tuareg]

How do you know you’ve had no issues? If high temperatures are causing the battery to degrade faster you won’t see any effect now, you’ll see it after ten years and 200,000 miles when your SOH is 80% instead of 85%.

Maybe but batteries will cost a fraction of the price in 10 years, will have better technology and there will highly likely be industry in battery upgrading existing EVs as there will be a massive market for this.

 

[Kithmo]

How do you know you’ve had no issues? If high temperatures are causing the battery to degrade faster you won’t see any effect now, you’ll see it after ten years and 200,000 miles when your SOH is 80% instead of 85%.

I'd be well chuffed if my battery was at 80% SOH after 10 years. ?