Battery Life and Always Parking Under the Sun in Hot Weather

ARK

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Yesterday I read somewhere that with many electric cars, if you park under the sun on a hot day, the car will want to turn the a/c on to keep the battery cool, even if you are not driving, not about to drive, and not having finished just driving.

I’d never heard of this before. Would the MME be expected to do the same? I live in Los Angeles, and do not have parking in the shade. Even when it’s a relatively mild (for LA) 80 degrees outside, we all know how hot a car under the sun can get.

If I don’t keep the MME plugged in, how much battery damage would the MME suffer after, e.g., five years? I’ve had my 2006 Mustang GT for over 14 years now and would like to keep the MME indefinitely too if it’s a great car, but would my battery go kaput under the Southern California sun after a few years?

I also don’t think I’d want to leave it plugged in. If the a/c would kick in, for example, whenever the cabin hit 100 degrees, then on a parked car under the sun in LA, we are talking about the a/c running, what, maybe 10% of all time in any given year? Seems like a huge energy drain.

Anyone with experience with other electrics know how much of a potential issue this could be for a MME?
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Billyk24

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The basic designed and air cooled hvb vehicles do have an issue. My Ford Cmax hvb acts as a heat sink. Yesterday, it sat in 82f sun for 45 minutes as I was inside at my dog doctor. The hvb temperature rose from 83f to 86f! Will the Mach e have active monitoring while sitting in the parking lot is unknown to me.
 
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I’d never heard of this before. Would the MME be expected to do the same? I live in Los Angeles, and do not have parking in the shade. Even when it’s a relatively mild (for LA) 80 degrees outside, we all know how hot a car under the sun can get.
Just a guess, but I would think it would know enough about outdoor temp and just run a fan for the battery if it's only 80 out and the battery was getting hot. Generally lithium-ion batteries are good to operate upto 130, but they should be below 113 if charging.
 
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You can learn from other EV's on this. Parking under the hot sun is possible, but car BMS will kick in from time to time and cool the batteries. You WILL lose some energy, otherwise batteries will start fast degradation. If you can plug in the car, BMS will work more aggressively and cool down batteries more often and even more save battery life.

So - for optimal battery management - plugin when you are in a hot area (like me in Texas).
Even in my garage, I can get 100 degrees during hot day's.

As for 14 years - I think no current EV car will provide you good battery performance 10 years from now. EV is evolving and is not a good investment if you plan to hold it for 14 years.
 

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I have a couple of tesla powerwalls and they drained at about 3% a day while idling before approval to turn the system on. With an EV, you probably should plan to plug it in once a week (maybe once a month as they are pretty big) even if not driving it and you can't leave it plugged in the whole time.
 
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Does battery charge have any effect on it? For example, if I kept the battery at no more than 50% charge in really hot weather would that increase its heat tolerance, or is amount of charge irrelevant to max safe battery temperature?

That’s true about 14 years, I would expect to probably have to replace the battery if I kept the car that long, but hopefully in the 2030s, battery costs will be much, much cheaper than they are now. I suppose my concern is more about seeing big battery degradation after even only a few years if the car was always under a hot sun.
 

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Would be nice if Ford released the manual early... I would think most of this would be covered in there instead of us guessing...
If they did that it would be great for a lot of things, not just this question. Unfortunately, my guess is that they will be updating it into october as they tweak/fix things in the software.
 

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Note that the battery is located in the very bottom of the chassis and heat rises. (Although if you do park on top of hot asphalt that can raise the battery temp.)

Also note that the battery is a large thermal mass in that it will heat up pretty slowly when simply parked (its different when charging/driving since the heat in that case is generated internally to the battery).

The Focus Electric, with its batteries under the seat and in the rear cabin didn't really have to engage the cooling system that often for me, if at all during hot days (yes I'm in Michigan which is different from LA, Phoenix, etc. where it is frequently hot but we do, occasionally, get a 90+F day).
 

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Everyone of us has active experience with car heating in our present vehicles, mostly at our homes. In my case (I live in Puerto Rico) I have two open carports (unenclosed garage) with just one wall. The open part faces the west so I get evening heating every day, and getting more now in this hot summer (up to 96 degress). So most of us already know how much sun heating we will get with a new electric vehicle, and we can do something to get less.

If your workplace has no shaded parking, I suggest change the parking space to get less sun (even if you have to walk further), or ask if you can put up a temporary shade or carport. I also recommend buying a well made reflective windshield shade to keep the interior cooler. This is most important for Ford vehicles (such as mine) that have all black interiors. I can recommend one brand if anyone needs it.

As for heating effect during some days when parked outside, I believe that the damage is minimal or too light to be measured, so I suggest treating an EV a bit better than a regular vehicle. But always try to get shaed parking, even if that parking has an hourly rate. It is a small cost compared to the possible vehicle heating.

We must do whatever to reduce sun damage to our present and future vehicles to extend their lives and enjoy driving them. My past vehicles were sold with no paint or body damage after twnety years of sun and heating effects.
 

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I know someone who drove an early 2000s Honda Civic Hybrid to work here in Phoenix, and parked it in a large, unshaded, virtually treeless lot, for about 12 years before replacing his battery. But it was pretty worn down by then, and it was air cooled, and it was NiMH and not Li-ion. So lots of differences. :)

Frankly, I think the "modern" EV landscape with actively managed Li-ion packs is too young to know how well they'll hold up in 15 years.

All we can really see is that manufacturers are offering 8-10 year pack warranties, and some of these warranties specify pack capacity will remain 70% or greater by the end of that period. So we can reasonably expect packs to hold up to that level in the worst climates.

LA at 80 degrees is nothing compared to hotter places like Death Valley. I wouldn't be too worried about it. Here in Phoenix we've reached 110+ degrees on more than 50 days so far this summer. And I'll need to park outside in that giant lot. But I'm not too worried about the pack at this point.

Nissan Leaf on the other hand? Immediately removed that one from consideration because its battery is guaranteed to decline more rapidly here in Phoenix. That vehicle relies on ambient air to cool the pack.
 
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Thank you, these are all reassuring responses. I guess I will also try to park on my concrete driveway instead of asphalt street so the pavement won’t be as hot.

I specified the light interior on my order for my own comfort, but having now learned about this potential need for heat management, I’m definitely glad I went with that option. Probably could have/should have gotten a breezier color, but the rapid red looked so good.
 

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My Focus Electric will only cool the battery when in ready mode or plugged in. I am not aware of any feature that will activate the cooling system while parked and unplugged. It's very hot here during the summer. I think we set a record yesterday (around 115 degrees). Sometimes, when I walk past the garage I can hear the compressor and fans running because it's cooling the battery pack. When I get home from work, I plug in and within seconds the cooling system kicks on. I have my charging times set for midnight to 5 am so it's not turning on because it's charging...it turns on because it's so hot outside.

I have Level 2 at work and the same thing happens. Sometimes the cooling system will just turn on all by itself but that is because the car was plugged in. If unplugged....it won't attempt to cool itself. Of course, this is only an issue during the summer months. The rest of the year it's a non issue so people in mild climates don't need to worry about this very much. Southern California by the coast is fairly mild so I wouldn't worry. Just find a shady spot to park if you can and you should be fine.

Our C-Max Energi doesn't have liquid cooling for the battery pack but it does have a forced air fan system and the same cooling scenario applies. It will only run the fans when plugged in. If unplugged....no cooling.

I presume the MME will have the same strategy but I could be wrong. They did use Tesla as a benchmark so perhaps there is a feature where you can enable battery cooling while parked. In that scenario, I presume you would want to select a minimum SOC level to ensure you have enough range to make it to your next charging point.
 

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This is the message I get every time I put the gear selector in Park with ambient temps at 97 degrees or higher.

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20200906_100025.jpg
 

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This is the message I get every time I put the gear selector in Park with ambient temps at 97 degrees or higher.

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20200906_100025.jpg
I sure hope that warning is no longer needed on the Mach-E.

I may need to read certain parts of the digital owners manual during my test drive, if we can't get access to this type of info sooner.
 
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