Tesla making HUGE mistake with Superchargers

[Earl]

I suspect that the 20% 'rule' is a combination of a few things:
1) leaving it at low SoC (State of Charge) for a long time, just like leaving it at high SoC is not good for the battery. When the battery gets below 20%, its close to a damage point so one should get it on a charger.
2) 20% may be a bit above the danger zone and there may be some safety buffer, however, self discharge happens. I know of Roadsters that whose batteries were bricked when owners drove them hard down to a relative low SoC, then parked them for a long time. The pack self-discharged to a point where it was destroyed.
3) also remember that a battery is as good as its weakest cell. It is very difficult for the BMS (Battery Management System) to know if one or more cells is at the danger point, even if most cells are fine. Cell balancing may not be perfect when there are thousands of cells.
Essentially, it is a good "rule of thumb", even if it is not a solid law of physics.

 

[ucmndd]

1) leaving it at low SoC (State of Charge) for a long time, just like leaving it at high SoC is not good for the battery. When the battery gets below 20%, its close to a damage point so one should get it on a charger.

This just isn’t true though. It’s forum lore. There’s nothing “not good” about lithium batteries at low states of charge.

 

[bradtem]

This just isn’t true though. It’s forum lore. There’s nothing “not good” about lithium batteries at low states of charge.

Well, really low SoC, like 3 volts, is not good but more recent searches don't show the promotion of the 20-80% cycle as ideal as what was said when I started driving. (Well 63% is actually the ideal maximum but nobody wants to limit it that much, so the slight extra cost of going higher is fine for most people. However, I store my car long term at 63%.)

 

[Hayseed_MS]

No. We've been through this. Neither V2 or V3 sites as deployed would meet NEVI requirements even with a CCS connector added. They would have to add power, transformers, cabinets, credit card readers, displays, etc. So it isn't a matter of opening the Superchargers, it would be a matter of redesigning the entire experience. (As well as adding a 24x7 call center that could take payment over the phone and start charging sessions.)

This whole thread is a great discussion but I have not stopped laughing envisioning Tesla with a 24x7 call center...

 

[israndy]

Have you never called for Roadside Assistance? I have had my car not Supercharge, twice, and one driving error issue. They have been prompt and courteous, and usually had the fix (reset the car), or the solution (the closest service center is in Salt Lake, 5 blocks away)

 

[Earl]

This just isn’t true though. It’s forum lore. There’s nothing “not good” about lithium batteries at low states of charge.

Please do not spout things about which you are ignorant. Someone might unwarily believe you.

Clearly, you've never seen a bricked battery because it was left low and discharged to where it could not be revived. I have.

There is a reason that your Tesla will tell you that you should plug it in soon when you stop it at a low SoC. That is not forum lore, it is direct guidance from Tesla.

I'll also quote directly from the Model 3 Owner's Manual (Model 3 Owner's Manual | Tesla):
"
There is no advantage to waiting until the Battery’s level is low before charging. In fact, the Battery performs best when charged regularly.

Note
If you allow the Battery to discharge to 0%, other components may become damaged or require replacement (for example, the low voltage battery). In these cases, you are responsible for repair and/or transporting expenses. Discharge-related expenses are not covered by the warranty or under the Roadside Assistance policy.
"
and
"

Battery Care​

Never allow the Battery to fully discharge. Even when Model 3 is not being driven, its Battery discharges very slowly to power the onboard electronics. The Battery can discharge at a rate of approximately 1% per day, though the discharge rate may vary depending on environmental factors (such as cold weather), vehicle configuration, and your selected settings on the touchscreen. Situations can arise in which you must leave Model 3 unplugged for an extended period of time (for example, at an airport when traveling). In these situations, keep the 1% in mind to ensure that you leave the Battery with a sufficient charge level. For example, over a two week period (14 days), the Battery may discharge by approximately 14%.
Discharging the Battery to 0% may result in damage to vehicle components. To protect against a complete discharge, Model 3 enters a low-power consumption mode when the displayed charge level drops to approximately 0%. In this mode, the Battery stops supporting the onboard electronics and auxiliary low voltage battery. Once this low-power consumption mode is active, immediately plug in Model 3 to prevent a jump-start and low voltage battery replacement.
"

 

[ucmndd]

Please do not spout things about which you are ignorant. Someone might unwarily believe you.

Good advice all around. You should consider it in the context of your own comments.

A lithium battery allowed to completely discharge can indeed be irreparably damaged.

But this isn’t a linear thing as your original post suggests, and the car will go out of its way to save your bacon if it gets close to a displayed 0% (which is still several kWh away from a “real” 0%).

Your original post - “leaving it at low SoC (State of Charge) for a long time, just like leaving it at high SoC is not good for the battery” is just plain wrong. There is absolutely nothing “not good for the battery” about leaving it at 20%, 10%, or even 5% state of charge indefinitely. In fact, this would be ideal to limit the effect of calendar aging on the cells if you were planning to store the vehicle for a long time.

Yes, ideally you’d want it plugged into a charger to ensure it can’t discharge to that critically low state where bricking happens - but again, just being at a low state of charge is not damaging in the least.

 

[Earl]

There is absolutely nothing “not good for the battery” about leaving it at 20%, 10%, or even 5% state of charge indefinitely. In fact, this would be ideal to limit the effect of calendar aging on the cells if you were planning to store the vehicle for a long time.

While I'm no battery expert, myself. I've been told the opposite of this by many who are battery expert regarding various battery chemistries including Li-ion.

Since you and I are both just bozos with computers on the internet, it is probably best for other readers to act in caution and heed my advice and Tesla's, not yours as ours definitely won't hurt, yet, there is evidence that yours might.

 

[bradtem]

While I'm no battery expert, myself. I've been told the opposite of this by many who are battery expert regarding various battery chemistries including Li-ion.

Since you and I are both just bozos with computers on the internet, it is probably best for other readers to act in caution and heed my advice and Tesla's, not yours as ours definitely won't hurt, yet, there is evidence that yours might.

Leaving aside the debate about what the risks are of low SoC, TIL from another thread that Tesla does not precondition a battery below 20% SoC before charging. One reason of course is to not waste the energy preconditioning if you are that close to the edge. If this is true, they presumably have a reason for it, but more to the point it means if you arrive at a charger with just 5%, you will not gain as much fast charging from it as hoped.

 

[MP3Mike]

Since you and I are both just bozos with computers on the internet, it is probably best for other readers to act in caution and heed my advice and Tesla's, not yours as ours definitely won't hurt, yet, there is evidence that yours might.

Your advice is don't go below 20%. Nothing in Tesla's advice says that. They just say don't discharge it to 0% and leave it there. If you drive down to 3% and charge you are still following Tesla's advice. So yeah people can follow Tesla's advice, just don't tell people it is different than it actually is.

 

[israndy]

Exactly, pulling in to charge at 0% on a road trip gives you the FASTEST recharge. If you drive to a charger from your home first thing in the morning it will not have preconditioned, even if you have a lot of battery it will not have preconditioned much, but on a road trip your battery will still be warm from the last recharge so driving down to zero means you spend the least amount of time at the charger for miles drivable afterwards. I can usually get to 65% in about 15 minutes.

And if doing this is killing my battery why am I at ~125,000 miles and still charging to 299 miles when I charge to 100% in my 2018 TM3 LR RWD? That's down from my original advertised 310 that I never saw go higher than 305 miles. I know, I'm just giving you a single sample, that's anecdotal. Also driving to zero is risky if the estimate is off for some reason, I usually shoot for about 7% remaining in the summer and 12% in the winter, but I have NEVER not made it to the next Supercharger.

OK, like others have said here, you are confusing driving the battery to zero and LEAVING the battery at zero. I have arrived at a hotel at 5% a mile from the Supercharger and in the morning woke to a frozen battery that showed 0%, this extra was then used to warm the battery before it allowed charging from the Supercharger, which is another thing that kills batteries: trying to charge them when they are freezing. Without reserve capacity to run the heaters you can do damage, so you don't wanna run it to zero and not charge it immediately.

So Tesla is trying to keep people aware that the battery needs to be charged for the long haul, but as has been repeated above it doesn't damage it to use it, just don't use it up and then walk away. With 20% in the battery you could walk away for weeks and it could still be charged back up just fine, but if you go to 0% and walk away for months you may kill the whole pack. It's dramatic what happens to those batts when they deep discharge, not 0% discharge, very different things

 

[avs007]

2) 20% may be a bit above the danger zone and there may be some safety buffer, however, self discharge happens. I know of Roadsters that whose batteries were bricked when owners drove them hard down to a relative low SoC, then parked them for a long time. The pack self-discharged to a point where it was destroyed.

The roadster was a special case, because the original roadster, (at least until v2), didn't have a separate 12v battery. So if you ran the main battery too low, it wouldn't be able to power the low voltage system, making it so it couldn't charge either.

 

[threeputts]

Exactly, pulling in to charge at 0% on a road trip gives you the FASTEST recharge.

It’s been my impression that the max rate is reached fastest starting at 9-10% (LRMY and LRM3). The few times I’ve plugged in at 5% or less it’s not as quick to reach the max rate.

 

[bradtem]

It’s been my impression that the max rate is reached fastest starting at 9-10% (LRMY and LRM3). The few times I’ve plugged in at 5% or less it’s not as quick to reach the max rate.

Of course, the main reason you don't pull in with zero percent is that's cutting it too fine on a road trip. When you plan what charger to use, you don't aim for one that you'll get to with zero. Ideally you don't aim to be below 10 as there is too much risk that the prediction is wrong, or you'll take a wrong turn or similar. In the future, when there is a charger every 10 miles, you might be better able to pull in with zero deliberately.

Even when I pull in with 10% and precondition, it's not long that the car starts backing off from the peak rate, at least in my experience. Just a few minutes.

 

[israndy]

You might be right:

It's been awhile since I did charger testing, I usually aim for 7% in the summer and 12% in the winter as I mentioned earlier.

 

[bradtem]

Reviewing the NEVI requirements:

- EV charging infrastructure includes at least four 150kW Direct Current (DC) Fast Chargers
with Combined Charging System (CCS) ports capable of simultaneously DC charging four
EVs;
- EV charging infrastructure has minimum station power capability at or above 600kW and
supports at least 150kW per port simultaneously across four ports for charging;

I would say that a typical Tesla V3 (or even V2) station has at least 4 150kw stalls certainly "capable" of simultaneously DC charging four EVs. That is what they will do if there are only 4 cars in the station, so they are capable of it. They will not always do it.
They tend to have more than 600kw at anything but the small stations, and they support 150KW simultaneously across 4 ports.

The regulations don't seem to say "always." Now, one might argue this is what they intended, and perhaps they did. But on the other hand what Tesla builds, with 8 stations using 750kw for example, is actually more what drivers would want than 5 stations, each one guaranteed 150kw. A Tesla station certainly does the right thing and follows the letter of the regulations.

Now, even if this interpretation were to fail, Tesla could fall back and offer two (or more) memberships. 150kw club members would pay more, but be assured of 150kw while their car can take it, if they can get one of the 4 Nevi-designated stalls. If the stalls are full, they can wait or give up the guarantee. People who don't select the 150kw club do not get the guarantee, and may pay a lower rate.

This meets every interpretation of the rules for CCS cars who are in the 150kw club, which is open to all who will pay the fee.

 

[pdx_m3s]

I just came here to say that, in my opinion, the Supercharger network should remain exclusive to Teslas. That’s all.

 

[israndy]

This is tearing the Tesla community apart, brother vs brother, can't we all just get along?

 

[honoraryorange]

I think it makes sense to expand it, but Teslas should never have to wait for non-Teslas, since we bought into this network and are (effectively) trapped into it without paying extra. If they implement some queueing system that prioritizes Teslas, that'd solve everything.

 

[moa999]

I just came here to say that, in my opinion, the Supercharger network should remain exclusive to Teslas. That’s all.

Are you Elon ?
No. Ok then.

Put simply, it will happen whether you or I like it or not.

It's basically baked into the new mission statement - "to accelerate the world’s transition to sustainable energy"