Dead Battery Experience

[Rusty1]

I can't believe there isn't already a thread for this. Point me in the right direction if there is. Here is my experience.

I have a 2012 P85 VIN#...413. I have had the car a little over a year. Great car! My mom lives 170 miles from me. I normally charge to 100% to be safe. We cut it close in the winter one night when the temp was about 12 degrees. We had 17 miles left when we got home. A 100% charge gets me to about 244 miles.

Yesterday I decided to try only charging to 90% for this trip. 220 miles range for 170 mile trip seems reasonable. BTW the trip is mostly interstate. Navigation started out telling me I would have 6% battery left when I arrived. I could live with that. Off we go and I am getting slow down messages the whole way, but I keep it set on 72 mph. After it got dark, the remaining percentage started to drop. First 4%, 2%, 0%, -2%. Now I get a little nervous. I decide to press on. I had heard you have approximately 12 miles spare range. Let's see what this thing can do. I did have a supercharger option in Nashville that was about 30 miles out of the way.

After two warnings to find a charger, and 10 miles from mom's, the car starts shutting down and says to safely pull over. The range says we have 9 miles left. So much for he 12 miles of spare range rumor. I am losing speed, but luckily am near an exit. I get off and basically coast into a gas station. I probably drove 1.5-2.0 miles after the shutting down message.

Now what, call mom, call wrecker, charge here, phone a friend? I call mom and let her know we are stuck. She is not comfortable driving after dark to pick us up. I try to call a wrecker - no answer. I look around for a plug. There is one on the side of the building. The car won't start and says battery too low. Nor will it go in neutral to let me try and push it 50 feet to the plug.

Finally I ask a guy getting gas next to me in an RV if he has a generator and can I get a short charge. He nicely agrees. We plug it in for about 10 minutes. BTW the range went to zero as I coasted to a stop. It still showed zero but would start and I pulled over next to the 110V plug. I gave his kids two bucks each to buy some candy and thanked him.

Now the 110V plug was dead. A nice attendant at the store helped me plug into the ice machine plug nearby. Luckily, I have an extension cord to reach. It starts charging at 3 mph ): They tell me I can charge if we donate to their children's campaign. I gladly give them 20 dollars. We call my sister to pick us up and we leave my baby there at the gas station.

It took about 4 hours for the range to read above zero. Now nine hours later, it reads 21 miles. We are going to get it at six this morning. No fun, but it could have been worse. I paid my sister $20 for her gas. All total this is going to cost me $44. Could have been much worse.

Lessons learned:
1) Navigation is accurate- range is not. I am disappointed with only getting 160 miles from 220 miles of range. I averaged 336 wh/mile for this trip.
2) My battery goes dead at 9 miles of range.
3) Anytime navigation gets below 5%, look for a charger.
4) Always charge to 100% to go to mom's.

 

[boaterva]

Glad you got it sorted out... the major factor here was the cold weather which will cut your range down. Slowing down will always add tons to your range, and you would have most likely made it later than originally estimated but a lot earlier than all the time you spent at the gas station!

 

[dweeks]

"Off we go and I am getting slow down messages the whole way, but I keep it set on 72 mph"

The real lesson is SLOW DOWN. If you had slow3d down 10 MPH when your margin dropped below 5 miles you almost certainly would have made it.

 

[Az_Rael]

I think whether or not you have a “buffer” depends on how balanced your pack is. If you haven’t balanced your pack in a while, all bets are off down that close to zero.

Also, when it decides to shut down is dependant more on your instant draws vs your average I believe. If you were accelerating from a stop sign or traveling up a hill during those last few miles, the car is going to shut down earlier.

 

[AB4EJ]

I have noticed some variation between what the system shows as an initial estimate and actual range (both plus and minus).... I guess it's because the navi computer doesn't know all the variables that can affect range, including temperature, headwind/tailwind, and load. I have found it is important to allow more range than you think you will need, i.e., charge more (even more than the car estimates), Another variable is that you may be forced to take a different route than the navi planned (construction detour, missed exit on interstate, etc.) which burns more power than planned.

 

[Darmie]

5) Carry a spare extension cord.

I read on line where the cool weather can cut the range by as much as half. I would think the biggest consideration to this is the battery temperature management which is easy to over look. Living here in Texas it will be easy to forget this. So, I hope I remember to plan accordingly if we take any trips North during Winter.

 

[Dax279]

Depending on the conditions. In winter driving I budget to have about 55% to 60% of my battery capacity depending on conditions. At 12 degrees F which I suspect is about 10 celcious I would likely have estimated you would get 70% to 80% range being conservative and assuming conditions were pretty good with not much elevation differences.

Forgot to add that my percentages would be based off driving at 120 km/h.

 

[Electroman]

The real learnings here are:

Sub zero cold weather is a real energy drainer. In multiple ways.

- Heating the cabin and battery,

- higher air resistance

- and most importantly less usable energy available in the battery during extreme cold weather. The battery never gets a chance to warm itself enough to get to an optimum temperature. In this trip you consumed 0.330*170 = 56 kWh. Since you charged to car to 90% this means your full bartery can only hold 56/0.9 = 62.3 kWh.

Obviously even with degradation you may have close to 70kWh, but at this low temperature and at your rate of discharge you were only able to extract 62.3kWh. On a good 70F day and driving at 65mph you would have been able to drive the full 220 miles or even more at 300 wh/mile.

Keeping the speeds down will generally get you to your destination much quicker than having to charge your battery on the way, or worse getting stranded.

 

[KJD]

Use the Energy screen to view "projected" miles instead of rated miles. As others have said slow down and you would have made it.

 

[Lasttoy]

First, never depend on the computer, I found on last two trips it was really off by 20 miles.
I have 2013 with over 102k on it and charging, draining is fun. I have kept a log, and I have never had same results.
Second, This is summer, it shouldn't affect the given miles.
Third, when traveling that far on a leg, always charge extra 25 miles at least. I found on a 5 leg trip, the computer would say I Could leave now. But half way thru the leg, it said I would arrive with 5%. Dangerously low in traffic.
Last, I have found the computer always lies in millage remaining. This might because this is a 2013 with 102k on it, so I always charge an extra 30 miles when going out of town.

 

[Don85D]

Our solution to range anxiety when touring longer distances is to allow 100km of range as buffer when planning charging station stops and to charge to the full 100% of battery capacity at each stop. Our pace may be slower but Superchargers tend to be in convenient places to waste some time. The 100 km reserve buffer is for the case when a Supercharger is unavailable and I need to find an alternate source.

We always carry a CHAeMo adapter and enough charger access cards, adapters and extensions to connect to almost any power source.

We watch the consumption chart just in case head winds are hurting us and only once did we reduce the risk by stopping at a Nissan dealer for a charge. They treated us to coffee while we waited so no hardship.

My backup to the backup would be the Plugshare App for a nearby EV owner.

Pushing the limits of battery capacity is like flat lining for fun. We prefer mitigating risk when we travel. Then again, we are older.

 

[NeverFollow]

but I keep it set on 72 mph

Yes, a lower speed would have helped. Better safe than sorry!

Tesla drivers claim Model S distance record of 670 miles on one charge

 

[LoL Rick]

I had heard you have approximately 12 miles spare range. Let's see what this thing can do.
...
Navigation is accurate- range is not. I am disappointed with only getting 160 miles from 220 miles of range. I averaged 336 wh/mile for this trip.

I would like to address these two bits from your story. Not to pick on you because you've learned these lessons. More to emphasize the point for those reading later.

There is no buffer beyond 0! That topic has come up several times on TMC and somebody always says "but I did it and got x miles beyond 0." That is pure luck based on the fact that determining the amount of energy in these batteries is not an exact science. The next person who tries it, like yourself, may not be so lucky. In fact @islandbayy posted a thread about the same sort of thing a couple years ago. His car shut down on the road in the middle of a brutal Wisconsin winter because all of a sudden the pack got too cold and decided to heat itself. Moral of the story: pushing the pack close to 0 is a complete gamble. Any buffer beyond 0 is pure luck.

Secondly, 336 Wh/mi is not the rated consumption for your car. It's closer to 290. Meaning if your consumption is anything higher than 290 Wh/mi then you will not get rated range. In practice, I have to keep mine down around 280 to achieve rated range and that is almost impossible at over 65 mph. Moral of the story: when the car tells you to slow down, slow down.

 

[Electricfan]

I admire your courage in testing the car's limits. I could never do that. I've done several long trips and I never leave a charger with less than a 50 mile cushion. I bring up the "trip" energy screen, and don't leave until it says I'm going to arrive with 20%.

There's another reason to do this, btw. You really don't want to drive with your battery near zero often. Its not good for it.

 

[No2DinosaurFuel]

Did you have the 21 inch rim? If so subtract some range just for that. I got a loaner once and it was 2013 p85+ with 21 inch rims. The range i got was consistently lower than the rated range at the same speed on the same road with same traffic speed conditions as my 90D on 19 inch rim. Also I think the newer cars are more accurate in its rated miles estimation.

I think tesla should really change their rated miles base on the type of rims you have.

Anyways still having 9 miles left and it actually stop working, I would ask tesla to cover the tow cost. But it looks like you actually were able to run until it shows 0, though it did drop faster than you expected near the end.

The lowest I got mine to was 12 miles and I was still kicking at full 74mph. So it might be the p85 are more power hungry somehow compared to the newer cars.

 

[Rusty1]

I appreciate the good will and advice from everyone.

BTW I retraced my wife's tracks before picking me up and we got 175 miles from our 90% charge. I can't believe I didn't think to look at mileage since last charge. There was a lot going on.

I want to be clear I don't recommend testing your limit. It can be dangerous and it is not good for your battery. I get it about slowing down. I have done it many times. It is an extremely boring but effective solution to more range.

I consider my experience a single data point on MS battery performance. Here is what I see as that data.
1) THERE IS NO RESERVE!
2) Range can be off by 9 miles. IMO it should read zero before going into shutdown mode. That allows you to be looking for an exit or pullover spot.
2) Navigation can be up to 2% off. It showed -2% and I was -4%. I still trust navigation the most.
3) Owners should plan at least a 50 mile (80km) cushion into trips. I.e. With my 244 range, I should not expect more than 194 miles without charging. From my experience, I increase that by 15% to 65 miles when the outside temp is below 15F.
4) If you go into shut down mode, you cannot put the car in neutral. IMO you should be able to do this as long as you have 12V power. This makes getting a tow more difficult. The tow truck must have a generator to charge enough to use neutral or a jack and rollers to put under the car.
5) You only get about one mile after shut down mode starts and the power goes down quick.
6) Tesla is an awesome road trip car when used with the common sense of having some margin. Trips are only going to become easier as more chargers of all type are added.

Someone asked about my tires. I have 21 inch.

I hope my experience helps others avoid running out, and if you do, what to expect.

 

[KJD]

For anyone wishing to avoid the dead battery experience there is a great post written by Doug from 2013 but it still applies today.

The Rules of Model S Road Tripping

 

[David99]

Cases where the car shuts down before it shows zero miles left are very rare. In almost 4 years of reading here, I only remember 3 cases and 2 of these cases the driver ignored the battery condition and drove fast despite warnings.
The number of cases where people were able to drive more after the car showed zero miles left is large. Many have done that. I have done it many times as well.

The thing people don't understand and causes confusion is that a battery is not a container that holds a certain amount of energy like a gas tank holds the liquid gasoline. Driving fast at the end will use more gas per mile but won't affect the remaining gas in the tank at all. A battery is different. Depending on how you drive and temperature greatly affects the remaining energy of a battery. For example a cold battery has a higher internal resistance leading to higher losses when discharging. In other words you get less energy out. The rest is lost in the battery. High discharge rates are also causing higher losses. Since they are internal to the battery, you can't easily measure them. You see the result in a lower voltage at a certain state of charge. But since remaining energy in a battery can't be measured perfectly accurate (again it's not like a liquid that has straightforward physical properties that can directly be measured), the range estimate in a battery isn't arbitrarily accurate.

There is an official email from Tesla explaining the limited accuracy of the estimated range. In a nutshell: the car uses a mathematical model to calculate remaining energy. Especially in a partial state of charge the data from the battery doesn't allow an accurate way to determine the remaining energy. Over time the algorithm that calculates the remaining range can get a little off, especially when you partially charge/discharge the battery. Near a full charge and near a full discharge the data from the battery allows a more accurate estimate. What happens sometimes: the algorithm is a little off. Once you get close to zero the data from the battery shows a lower state of charge than estimates and you see a sudden drop.

It is NOT balancing! Balancing happens all the time and keeps the cells even very well. I have been monitoring the balancing of my battery for over 50k miles and under no condition was my battery pack ever so much out of balance that it would lead to even a single mile of lost range. The reason for fluctuations in range are due to the algorithm not being perfect.

Usually the car will side on the safe side. That's why there are so many people who were able to drive beyond zero miles left. It's not a built in buffer, it's the car's software staying on the safe side. In very rare cases the calculated estimate can be a little off in the wrong end and then you see a sudden drop of range and it hits at the worst moment.

If range is getting tight, the #1 thing to do is slow down! It makes a huge difference. Avoid strong acceleration! Drive 'gentle'. You can get more energy out of a battery if you discharge is slower, at a lower rate (= driving slower and accelerating lightly).

 

[Rusty1]

I appreciate the good will and advice from everyone.

BTW I retraced my wife's tracks before picking me up and we got 175 miles from our 90% charge. I can't believe I didn't think to look at mileage since last charge.

I want to be clear I don't recommend testing your limit often. It can be dangerous and it is not good for your battery. I get it about slowing down. I have done it many times. It is an extremely boring but effective solution to more range.

I consider my experience a single data point on MS battery performance. Here is what I see as that data.
1) THERE IS NO RESERVE!
2) Range can be off by 9 miles. IMO it should read zero before going into shutdown mode. That allows you to be looking for an exit or pullover spot.
2) Navigation can be up to 2% off. It showed -2% and I was -4%. I still trust navigation the most.
3) Owners should plan at least a 50 mile (80km) cushion into trips. I.e. With my 244 range, I should not expect more than 194 miles without charging. From my experience, I increase that by 15% to 65 miles when the outside temp is below 15F.
4) If you go into shut down mode, you cannot put the car in neutral. IMO you should be able to do this as long as you have 12V power. This makes getting a tow more difficult. The tow truck must have a generator to charge enough to use neutral or a jack and rollers to put under the car.
5) You only get about one mile after shut down mode starts and the power goes down quick.
6) Tesla is an awesome road trip car when used with the common sense of having some margin. Trips are only going to become easier as more chargers of all type are added.

Someone asked about my tires. I have 21 inch.

I hope my experience helps others avoid running out, and if you do, what to expect.

 

[islandbayy]

I would like to address these two bits from your story. Not to pick on you because you've learned these lessons. More to emphasize the point for those reading later.

There is no buffer beyond 0! That topic has come up several times on TMC and somebody always says "but I did it and got x miles beyond 0." That is pure luck based on the fact that determining the amount of energy in these batteries is not an exact science. The next person who tries it, like yourself, may not be so lucky. In fact @islandbayy posted a thread about the same sort of thing a couple years ago. His car shut down on the road in the middle of a brutal Wisconsin winter because all of a sudden the pack got too cold and decided to heat itself. Moral of the story: pushing the pack close to 0 is a complete gamble. Any buffer beyond 0 is pure luck.

Secondly, 336 Wh/mi is not the rated consumption for your car. It's closer to 290. Meaning if your consumption is anything higher than 290 Wh/mi then you will not get rated range. In practice, I have to keep mine down around 280 to achieve rated range and that is almost impossible at over 65 mph. Moral of the story: when the car tells you to slow down, slow down.

Actually, was in Ohio, on our way back from Niagara Falls. It was in the 50's on the way to Niagara, on the return trip, I believe around 5*F. For some reason, even with range mode on, due to the Low SOC (Was 3 miles short of making it to the Supercharger), the car decided to turn on the pack heater. No Public stations of any kind were available, closest thing was the supercharger.

That pack heater used up what little power I had left. I worked out that I would have made it had the pack heater not turned on. So instead of making it and letting the car have a nice drink from the Supercharger, we were stuck on the side of the road for hours, as no tow truck company would tow a tesla for fear that it would start on fire...... Nice police officer drove us to a hotel for the night, the car sat on the side of the freeway. The next morning, the police department forced a tow company to take the car to the supercharger.

I also had a instance where on a MS60 loaner, I had 10 rated miles left, and the rear brakes did not release after stopping at a stop sign, about 1/10th mile from the supercharger. I was so close, I decided to "ride it out". I mean really, I'm within view of the supercharger! Well, about 300 ft from the station, the car shut down. Of course then the brakes released..... And I at least was able to get it into tow mode, nice guy helped me push it... Up-Hill into the stall.

Here is a video from that incident.

Moral of the story folks, consider 0 to be 0. Unless you have can-bus access, and can read exactly how much power the car "Thinks" it has left, ZERO IS ZERO.