Staying at 7% overnight?

[OlofL]

I have no charger where I am staying this night, and I only have 7% SoC. I will leave tomorrow morning and go straight to a slowcharger, just a few km away. I have a LR Tm3 awd. I am staying in a warm garage at 14c.

I got a notification saying

"Battery charge level too low. Vehicle consumes battery while idle. Charge now to ensure vehicle will start and avoid potential battery damage".​

I haven't had any issues with vampire drain. But the last sentence scared me. Is it too long to stay 12h at that low SoC?

 

[electrictorque]

If the supercharger is not that far, I would go there asap and plug it in for a few minutes to get the battery over 20%. 5 minutes should do it.

 

[Tam]

...slowcharger, just a few km away...

A low State of Charge has unpredictable behaviors so I wouldn't take any chances.

What you see on the battery gauge can change (for the worse) quickly overnight in cold weather because what you saw when you stopped was reflective of the warm battery during a drive.

And in the morning, what you see on the battery gauge can also change (for the worse) quickly once you start your drive because the battery might want to heat itself up since you are now starting to drive.

I agree with @electrictorque. Prudently, you should charge first before you take your rest and not the opposite way that you suggested above.

 

[jjrandorin]

the OP says "go straight to a slowcharger". I am not sure if OP ment "go straight to a supercharger", but I agree with both other posts. Dont leave the car wth that low a charge overnight. You need to get some charge into the car before you bunker down for the night. Even if you get it to 10-15 %.

The car wont leave you stranded if you listen to it, but this is a case of "listen to it" in my opinion. If you are stuck in the morning you can NOT blame anyone but yourself, because the car is telling you not to leave it like that.

 

[KenC]

If you're in a garage, surely you can access a 120v outlet, or similar?

 

[OlofL]

If you're in a garage, surely you can access a 120v outlet, or similar?

No.

If the supercharger is not that far, I would go there asap and plug it in for a few minutes to get the battery over 20%. 5 minutes should do it.

No superchargers inside the cities.


And its not always convinient to "charge before rest" even I know its not good to leave car at low SoC. But thats just the way it is sometimes....


As I said im not afraid of going to 0% SoC.
Im more concenred of the battery longevity. Is it better staying one night at 96% than staying one night at 7%?

 

[M3BlueGeorgia]

No.

No superchargers inside the cities.


And its not always convinient to "charge before rest" even I know its not good to leave car at low SoC. But thats just the way it is sometimes....


As I said im not afraid of going to 0% SoC.
Im more concenred of the battery longevity. Is it better staying one night at 96% than staying one night at 7%?

Yes

 

[Tam]

...Is it better staying one night at 96% than staying one night at 7%?

Some people advocate the lower the state of charge the better and they would avoid reaching 90%.

I, on the other hand, subscribe to this 2013 post for battery longevity while on the road:

The Rules of Model S Road Tripping

While on the road, if I have to choose between high state of charge such as 100% and low such as 7%, I would choose high at 100% any time!

It says: "Sitting at a very low charge is not good for battery lifetime."

Put it in another way, low state of charge means you are endangering your battery longevity.

 

[EVie'sDad]

And if you are using the mobile app, staying connected will definitely drain up to 9 miles overnight. Go now and avoid a complete and potentially damaging shutdown overnight. Good advice to never let the battery dip below 20 percent to extend battery life.

 

[jdw]

Aside from it not being a great thing to do the battery, or the risk of the cold dropping the available energy further while you sleep, there is also the risk that the car will not charge the 12V battery if the main pack is left that low. A dead 12V would require a "jump start" before you could do anything with the car.

 

[Tam]

Aside from it not being a great thing to do the battery, or the risk of the cold dropping the available energy further while you sleep, there is also the risk that the car will not charge the 12V battery if the main pack is left that low. A dead 12V would require a "jump start" before you could do anything with the car.

Exactly. Not just about the main battery but also about the 12V battery that would be starved because of the main battery's refusal to share its charge during the low state of charge.

That is the chicken and egg dilemma. When the main battery is so low, it would not charge the 12V in order to save itself. But without the 12V, you can't do anything!

I might have misstated by saying "unpredictable behaviors" but these behaviors are to be expected for the low-State-of-Charge risk-takers.

 

[Kevy Baby]

Count me with another vote to go charge to over 20% minimum WHEN YOU GET BACK TO WHERE YOU ARE STAYING. So, if you think you will lose 5% driving back, then charge to 25%. When you leave in the morning, it will take another 5% to get back to the slow charger and you could very easily lose 10% overnight (especially in the cold weather), leaving you with only a 10% buffer. That's already too tight in my book.

 

[Fredneck]

I have no charger where I am staying this night, and I only have 7% SoC. I will leave tomorrow morning and go straight to a slowcharger, just a few km away. I have a LR Tm3 awd. I am staying in a warm garage at 14c.

I got a notification saying

"Battery charge level too low. Vehicle consumes battery while idle. Charge now to ensure vehicle will start and avoid potential battery damage".​

I haven't had any issues with vampire drain. But the last sentence scared me. Is it too long to stay 12h at that low SoC?

It probably depends on how far "a few km" are. I lose 1% a day on a 100 kWh battery, or about 1 kWh. If you car is in the temps you are talking about you should be fine to go "a few km" for low values of "a few".

I had exactly this problem a week or two ago with a loaner vehicle. I ended up getting a friend to pick me up so I could drop off my car at a level 2 charger over night. Even then, something happened that it dropped back from 24 amps to about 16 overnight and the car still only had 65% charge when I picked it up. Fortunately that was enough.

I had called Tesla about this because the car seemed to have lost a significant amount of range while sitting. They were not of much help unless I was truly stuck. Not only that, the guy on the phone told me the car would do what is required to maintain the current temperature of the cabin... not the battery, the cabin. I stopped talking to him at that point. That has to be wrong... right?

All my misadventures with the car are pretty funny to my friends. None of them will be buying a Tesla any time soon.

 

[ucmndd]

That 7% may well be 2-4% by morning after the battery cools.

You’ll probably be fine but don’t make a habit of it.

 

[Tam]

...the guy on the phone told me the car would do what is required to maintain the current temperature of the cabin... not the battery, the cabin...

My understanding is the comfort of the main battery is prioritized over the comfort for human.

That means, if it's sizzling hot outdoor, the cabin air conditioning might be diverted to the main battery and let human suffer in sweats instead of the battery.

And in the freezing cold winter, the heat for the cabin might be diverted to the main battery and let human suffers and shivers in the cold instead of the battery.

 

[user212_nr]

This is just a very unfortunate situation. Obviously owning an electric car, involves extra responsibility to plan your trips.

What are you going to do, spend the entire day tomorrow "slow charging", but not at a hotel or place where you could have slept...? I don't even want to know.

You haven't given the details of your route, but you traveled at least 80% (or started with little charge) and so it sounds like you passed a supercharger and neglected to spend the 30 minutes needed to get your car back to 80. Even if you didn't "pass" a supercharger, in that case you nevertheless neglected to route yourself past one.

If you need help planning your route, you can post your route.

 

[Missile Toad]

Some options, that I've checked on ( and sometimes pre-arranged):

• Local hotel, that I'm not staying at: I ask, "may I charge for 30 minutes on your wall connector?";
• Local hotel, that I'm staying at: I see you have a regular outlet, in the semi-circle drive -- Can I plug in overnight?
• Library that has a J1772 charger (plugshare.com found)... just plug-in, and Uber back to the hotel for 3/4 mile drive.
• Gas station, that is near my destination: "I'll chip in $5 if you let me charge to add 25 miles (overnight)."
• Moved around a cramped parking garage, to get around a non-charging EV (parking sideways and illegally) for at least 2 hour charge;

Look, after driving 3+ years and 20-30K miles, I've learned to get creative, go to the 'dark side', and generally think upside-down and backwards to get my car tiny amounts of charge that avoid the OPs situation. Park legal, park illegal, park on the grass, throw a charging cable between floors at the parking garage, extension cords, etc.

 

[Kevy Baby]

...cable between floors at the parking garage....

Now there' something I would have never thought to!

 

[rrolsbe]

Until recently, it was my understanding that the DC-to-DC converter would not top off the 12V AGM battery if the traction battery was below 20% but it appears that may not be true; likewise, 0% traction battery charge level is not truly 0 IE.. a bricked battery. That said, I hopefully never have to leave my M3 sit parked at or below 20% not plugged into some level of charging.

 

[Fredneck]

My understanding is the comfort of the main battery is prioritized over the comfort for human.

That means, if it's sizzling hot outdoor, the cabin air conditioning might be diverted to the main battery and let human suffer in sweats instead of the battery.

And in the freezing cold winter, the heat for the cabin might be diverted to the main battery and let human suffers and shivers in the cold instead of the battery.

You didn't understand the context. This was a conversation about leaving a car outside in the cold overnight with a low state of charge on the battery (no human involved). Besides, the AC and heat are enough to do both, heat/cool the battery and the passengers.