Low SOC = Terrible Supercharging

[JohnnyLounge21]

To address AEdennis's note, I also take the Trip Planner as a "suggestion" and nothing more. And, of course, I follow the route it suggests as most efficient, but I take the arrival SOC with a grain of salt. Especially when I'll be stretching the car for range.

To TexasEV's note, running down the loaner to -2% came as a shock having never stretched a Model S before (I feel my Roadster gives a better overall estimation of range and that was my EV experience at the time). In the loaner scenario I mentioned, I had 40 miles of range for a 22 mile journey on mostly flat ground with perfect weather and the availability of drafting on a semi half the way. My range decreased 2 miles for every 1 mile I got closer. I'll never put myself or my car in that situation again. I definitely don't feel "clueless" to have left myself 40 miles for a 22 mile trip.

kingjamez makes some great points. What I feel is missing is the communication from Tesla to owners to help us understand new measures they may be putting in place. 10 years ago I was told to run my flip phone battery as close to zero as possible and then charge it all the way up. A lot has changed since then. . .

Naonak summed up what I was trying to convey pretty much perfectly in both of his responses.

And the question remains as to how we feel about the lack of knowledge on the part of the folks I talked to at Tesla and the delivery manager that gave me the orientation. Why suggest the tow? Why not speak to the new facts about low SOC in the delivery seminar I had only 2 months ago?

Tesla certainly inculcates using the Range Mode as little as possible. Why not do the same thing with low SOC and also inform owners of the fact that you'll suffer an extra 20 min trickle at the front end of the Supercharge for good measure? Certainly would be an added deterrent to manage your road trip more conservatively and the battery would be in better health. Everybody wins.

 

[jchag]

This happened to me in December at Rancho Cucamoga. It was cold and I arrived with approximately 5 miles left on my S60 limited 75. Took 40 minutes to begin charging. I thought the car was broke and called Tesla. It wasnt the car or charger. The car would sit there and then charge would go up to 6KW then back to zero for a while, the it would happen again. Eventually it would go up to 8KW then zero, then 10KW then zero and about 40 minutes it began to charge a decent rate. I recently had my battery under 10 miles and arrived at Fresno SC, the vehicle never charged over 55KW. Moral of the story, I will have at least 20 miles left when I go to charge

 

[mspohr]

To address AEdennis's note, I also take the Trip Planner as a "suggestion" and nothing more. And, of course, I follow the route it suggests as most efficient, but I take the arrival SOC with a grain of salt. Especially when I'll be stretching the car for range.

To TexasEV's note, running down the loaner to -2% came as a shock having never stretched a Model S before (I feel my Roadster gives a better overall estimation of range and that was my EV experience at the time). In the loaner scenario I mentioned, I had 40 miles of range for a 22 mile journey on mostly flat ground with perfect weather and the availability of drafting on a semi half the way. My range decreased 2 miles for every 1 mile I got closer. I'll never put myself or my car in that situation again. I definitely don't feel "clueless" to have left myself 40 miles for a 22 mile trip.

kingjamez makes some great points. What I feel is missing is the communication from Tesla to owners to help us understand new measures they may be putting in place. 10 years ago I was told to run my flip phone battery as close to zero as possible and then charge it all the way up. A lot has changed since then. . .

Naonak summed up what I was trying to convey pretty much perfectly in both of his responses.

And the question remains as to how we feel about the lack of knowledge on the part of the folks I talked to at Tesla and the delivery manager that gave me the orientation. Why suggest the tow? Why not speak to the new facts about low SOC in the delivery seminar I had only 2 months ago?

Tesla certainly inculcates using the Range Mode as little as possible. Why not do the same thing with low SOC and also inform owners of the fact that you'll suffer an extra 20 min trickle at the front end of the Supercharge for good measure? Certainly would be an added deterrent to manage your road trip more conservatively and the battery would be in better health. Everybody wins.

I would never start a trip with only 40 RM unless there was no other option.
(In an ICE car would you start a trip with only one or two gallons in the tank?)

 

[whttiger25]

Tesla needs to change their "you have enough energy to continue your trip" calculations drastically then. I always arrive at the next SC low on charge. In fact, if I ever left when the message popped up, I'd be stranded. I always put a buffer in and still arrive low SoC. It's not clueless owners, it's clueless engineers.

God forbid an owner doing what the car says to do and then wondering why they are stranded. Or throttled.



It may positively enhance the life spans, but it is slowly sucking the life out of the car. If Teslas strategy is to sell one car that can do certain things, but then later nerf the car so it can't do any of those things to "protect it," then there's a major problem and disconnect somewhere. Either sell the car like it will function for most of it's useful life, or suffer the warranty consequences for selling a car that can't perform as advertised without breaking down. That's really the only two morally acceptable choices.

As an owner hoping to keep my car 10 years, with a battery that's warranted only for failure and not degradation, I don't mind Tesla using new research and testing results to further protect the residual value of my car, which is mostly tied up in the battery in that time frame. At times on my old 90D I became frustrated with charging rates, specifically maintaining peak charge rates for short times and then having them drop dramatically. However, when I walked away from the car, got some food, read the news on my phone, or did some shopping, and just simply gave it the 40 minutes you would expect to get that "10% to 80%" advertised charge, it usually got pretty close to that....maybe needing 45 minutes. In the end, I'd choose longevity of battery all things considered. I don't want a supercharger pumping 110kw into a 0% SOC battery just because....

I guess if I was leasing maybe I'd have a different POV?

I actually had more of a problem with faulty superchargers than the charging algorithm of my car itself, but that's another story....

And "sucking the life out of the car" definitely feels to be like a bit of hyperbole. Needing to wait another 5 mins at a supercharger? I think the life of the car is how it drives..... And after a few months doing trips and supercharging, I learned to toally ignore that time estimates in the NAV....I actually never used the NAV for a multi-supercharger trip, but rather just plotted the course to my next supercharger or final destination, and referred to the SOC graph to ensure I was predicted to arrive with AT LEAST 20% SOC. Never had a range anxiety scare doing this.

 

[kingjamez]

And "sucking the life out of the car" definitely feels to be like a bit of hyperbole. Needing to wait another 5 mins at a supercharger? I think the life of the car is how it drives.....

Totally agree. You know what real "sucking the life out of the car" is? It's Tesla realizing that something in the current battery management systems causes undue wear on the battery, and them not fixing it. The battery dies quicker, your car depreciates faster, and Tesla gets a bad name after their cars have been on the road for more than 5 years. That's really life sucking.

Further it's really (really) hard to predict the performance of a battery 2-5-10 years out without spending the corresponding 2-5-10 years. Real life is teaching Tesla and they are learning in real-time on real cars.

Those complaining about Tesla learning and then applying what they learn to make your car last longer, need to shift their perspective to looking forward, not backward.

Look at it in reverse. If it comes out in 3 years that a bunch of Tesla packs start loosing capacity rapidly, then we found out that Tesla knew how to prevent it, but didn't because "the car was sold with this behavior so we didn't want to change it"... Tesla would get murdered and this forum would blow up, three times over. Durned if you do....

I for one am really happy that Tesla has the ability to make changes to make my car better and last longer over time.

-Jim

 

[Bangor Bob]

Sounds like what Tesla really needs to do is to adjust their lower voltage cutoff limit to a point at a higher state-of-charge. Seems like the charger is doing a bottom-balance on the pack at very low SOCs.

Of course, doing that is going to cause the cars to have a different (smaller) kWh capacity, and may require a re-statement of EPA range, so it's understandable why they might want to resist doing that.

 

[whttiger25]

Sounds like what Tesla really needs to do is to adjust their lower voltage cutoff limit to a point at a higher state-of-charge. Seems like the charger is doing a bottom-balance on the pack at very low SOCs.

Of course, doing that is going to cause the cars to have a different (smaller) kWh capacity, and may require a re-statement of EPA range, so it's understandable why they might want to resist doing that.

Yeah, and I'd rather safely have more range if that means slower supercharging from 0-10%. Better to have the range. And if you don't like it, don't drive below 10%...

 

[Max*]

Tesla needs to change their "you have enough energy to continue your trip" calculations drastically then. I always arrive at the next SC low on charge. In fact, if I ever left when the message popped up, I'd be stranded. I always put a buffer in and still arrive low SoC. It's not clueless owners, it's clueless engineers.

God forbid an owner doing what the car says to do and then wondering why they are stranded. Or throttled.

And that's the difference. I always drive out before the message shows up. I think the message is too optimistic. So if they change it even more, i'd still drive out before the message appears.

 

[Naonak]

And that's the difference. I always drive out before the message shows up. I think the message is too optimistic. So if they change it even more, i'd still drive out before the message appears.

How do you get to the next supercharging stop? I find that it would be almost impossible for me to get to the next Supercharger if I left when it said to leave... leaving before that would be a total disaster.

 

[mspohr]

How do you get to the next supercharging stop? I find that it would be almost impossible for me to get to the next Supercharger if I left when it said to leave... leaving before that would be a total disaster.

Some people drive more conservatively than others.

 

[thefortunes]

How do you get to the next supercharging stop? I find that it would be almost impossible for me to get to the next Supercharger if I left when it said to leave... leaving before that would be a total disaster.

Based on my experience, the message is designed to leave you with 20% when you arrive at the next SuC (which also corresponds with the battery graph on the trip screen going yellow, then red below 20%).

Assuming normal weather, I can easily manage with less than 20% buffer.

 

[whttiger25]

And that's the difference. I always drive out before the message shows up. I think the message is too optimistic. So if they change it even more, i'd still drive out before the message appears.

This statement makes no sense to me. If the message is optimistic why would you drive before you get the message? Would that mean you would want to charge more AFTER you get the message?

 

[Max*]

This statement makes no sense to me. If the message is optimistic why would you drive before you get the message? Would that mean you would want to charge more AFTER you get the message?

Sorry, meant it's too pessimistic.

What I meant was: I don't wait for the message. I check the trip planner and what my SOC will be at the destination. And depending on the weather, how well I know the route, how well I know backup charging options, I'll drive out with an estimate anywhere between 3%-7% SOC on arrival.

The trip planner has changed FW version over FW version over FW version. Used to be 20%, then 7%, then 10%. Not sure now when it tells you to drive out.

 

[Max*]

How do you get to the next supercharging stop? I find that it would be almost impossible for me to get to the next Supercharger if I left when it said to leave... leaving before that would be a total disaster.

By driving?

But in seriousness, this has been discussed in the forums a lot. Some people get better than the projected graphs, some people a lot worse.

I'm one that gets at-or-better than the projections of the car, so I leave before it thinks I should have the 10% buffer or whatever it estimates.

There have been discussions about whether it's an east coast vs. west coast thing. A small battery vs. large battery. Car age. Etc. No definitive conclusion.

I drive with the flow of traffic (which is about 10-15mph above the speed limit on the east coast (so in a 65mph I might do 75mph, but in a 55mph, I might do 70mph)), I drive with 3 passengers, and crap in the trunk. I drive summer and winter. In summer I can beat the predictions fairly easily, in the winter I'm usually a little below (I guess it doesn't gauge it as well, dunno).

 

[Max*]

@Naonak: here this is from 9/2015 on a roadtrip, using the above driving criteria. Range mode on. Cabin temp at about 67-69. Outside temp on this trip was warm, it was 75F. But I've taken the same trip in 30F weather too, and gotten close to the line.

So I never listen to the "drive now" suggestion, since I'd always arrive with way too much SOC at the next charger.

 

[NoMoGas]

Remember, once ypu pass zero it charges the 12v battery VERY slowly first. In short, dont do that lol

 

[NoMoGas]

I wonder if the Trip Planner algorithm changes based on which batteries one has in the car. If you followed Trip Planner, would it have plotted a more efficient trip? I tend to ignore it and just take its suggestions as "novelty".

I believe it takes int your vehicles historical data. As someone who has gone coast to coast (and about to do it again) IF you leave when it says AND drive as recommended you WILL get there. The anxiety goes away once you realize the car warns you now to slow down etc. (It didn't used to do that). Monitor your "Trip" and you'll be fine.

 

[NoMoGas]

BTW HI DENNIS! lol

 

[AEdennis]

BTW HI DENNIS! lol

Going for the CannonBall Record again Jim?

I tend to take WEEKS to do that Journey vs your hours, remember. I like a more leisurely drive!

 

[mspohr]

@Naonak: here this is from 9/2015 on a roadtrip, using the above driving criteria. Range mode on. Cabin temp at about 67-69. Outside temp on this trip was warm, it was 75F. But I've taken the same trip in 30F weather too, and gotten close to the line.

So I never listen to the "drive now" suggestion, since I'd always arrive with way too much SOC at the next charger.

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Just a reminder that the energy graph shown in the quoted post is your friend. It's extremely useful to tell you how you are doing on energy use. At the start of a trip it will draw a graph with your predicted SOC. It accounts for terrain (and ? other factors). As you drive, it will adjust the graph to your actual energy use. If you notice you are using more energy than predicted, you can slow down and watch the graph recover. Before there were a lot of Superchargers, I used this a lot to "hypermile" on long stretches where I was worried about range.
(As you charge and if you have your next destination set in navigation it will show you the predicted SOC at your destination. When it goes from red to yellow or green, you're good to go.)