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Discussion in 'Model 3' started by Nuclear Fusion, Mar 8, 2019.
What say you?
Of course—Li-ion batteries degrade with heat.
BUT I do not expect any degradation due to high current charging will be enough to be noticeable over the cycle-based degradation. Basically, it’ll be lost in the noise.
I don't think Tesla would allow it if they thought it would significantly harm the batteries. Having said that, I don't think it'd be good to use these v3 superchargers on a regular basis.
I also think this whole 1000 mile per hour thing is largely a gimmick. I've seen the early charts of how much faster it'll charge from 8% to 90%, but if the charge taper begins at only 18%, then that is not the same as tapering at 50% or some other much higher percentage. They say "It'll charge 1000 mph". They don't say " It'll charge 1000 mph, but only for a few minutes".
This is a (lack of) truth in advertising. They only tell one side of the story. The part the non-technical masses can understand.
Will these be slightly more expensive then the V2 chargers, to start at least? Will they be pay only?
I rarely charge past 20-30% as I only use it to get home to .11-.14 cent energy. It will now take me more time to get off and on the freeway than it will do get the energy needed to get home. "To get home" is the intended use for these unless you are travelling 400+ miles in one day. But how often do we really do that?
No, because Model 3 was designed from the beginning to support Supercharger V3. See my message (second paragraph) from 2017 here. That's why the oldest Model 3 supports Supercharger V3 but the newest Model S/X don't.
Does that mean you maintain your battery at 20 to 30%? 30% out in the morning and 30% home in the evening?
I'm pretty sure he means that when you need a Supercharger it's when you are on a long trip. He charges it just enough to get him home where he can pay a cheaper rate.
The model 3 comes with an extensive industrial-grade liquid cooling system for the battery. Battery temperature is closely monitored, including during the charging cycle, and this is part of why the charge rate declines during the course of a charge... When the battery is heating up faster than the cooling system can handle it, it backs off on the charging power.
The new higher charge rates won't have much of a negative impact on battery life because the system is limiting charge whenever it's creating more heat than the system can handle.
The chart of power versus state of charge looks like V3 tapers the power just like V2, and starts tapering earlier when running at it's highest powers. That might run the battery closer to its limits for longer, but it still respects the same limits as V2. I'd expect very little difference in battery stress compared to V2.
Will it hurt at all? Probably some amount.
Will it hurt significantly? Hopefully/probably not.
Still, what I find most interesting is that it appears Tesla has changed the V2 taper curve when the Supercharger is not current-limited.
So this tells me Tesla (and/or Panasonic) engineers made an earlier determination back in 2017 of how many amps (or what C-rate) were acceptable at a given %SOC without causing excessive battery degradation, and they used that to formulate the taper curve, and now they have changed that earlier decision to allow more amps.
Without insight into what drove this decision process, we can’t know what the motivations or drawbacks are. Maybe monitoring real-time battery pack health in the existing Model 3 fleet has allowed them to empirically determine that they were unnecessarily conservative in their previous decision and could safely go higher without any drawbacks.
But it also seems plausible (or, IMO, likely) that they made a deliberate decision to accept a little more battery degradation (particularly in frequent Supercharging vehicles) order to reduce charging times, decrease SC congestion, etc.
Even the folks who were doing 100% of their charging via supercharger, to 100% battery, multiple times a day, were getting hundreds of thousands of miles out of their older-tech 18650 S/X batteries... so I wouldn't be too concerned about occasional supercharging on the 3 battery.
I think the general consensus here is correct. Tesla has been very conservative in their supercharger rates vs damage as proven by the data. Tesla battery degradation vs everything else is almost non existent. I suspect that the data allowed them to increase the rates with minimal impact. I would guess that it is not a zero impact, but relatively small and evaluated to be worth the convenience.
Pretty sure once everyone's free supercharging offering expires there will be even more availability at the stations.
With the new Superchargers, Tesla will have much finer control over charging.
Combine this the all the battery degration knowledge they have obtained over the years, and I suspect they wlll be able to allow faster charging, but still retain long battery life.
With Supercharging, we are talking about direct current to the DC batteries. No invertor required. This is the most pure way to charge the Li batteries.
Imaging that Tesla will roll these out to areas where the most congestion is being experienced. Later it will be implemented on the long distance route where travelers will enjoy the quicker, en-route charging speeds.
Well Tesla did state that too many fast charges will degrade the battery. I have not seen anything from them stating otherwise since then but I haven't read the whole I internet. Here's a quick article:
Tesla explains why it limits Supercharging speed after high numbers of DC charges
Do you not think that Tesla has already thought of that? I'm sure they know how to protect the batteries in their cars.
I'm 1000% they've thought of it but they need to tell the public. We can only go on their last official word.
That said, aren't a bunch of customer cars now permanently throttled?