What is considered a "long trip" when considering charging to 100%?

[Bouba]

I charge to 100% if I am going away overnight or the weekend....we do a lot of weekends away...usually about a 100 mile radius...so I do a bit of sightseeing at the destination...perhaps a small detour on the way back...and of course Sentry Mode will be on at all times...and I like to arrive back home without ever having to charge the whole trip

 

[UncleCreepy]

Presumably you mean 322mi/518km, assuming 18-inch wheels?

You are correct about the 18" wheels, but the car did in fact display 504 km max rated range when it was new. 480 vs 504 is not even enough difference for me to calculate how many % I lost. I even had a long trip from Eastern Ontario to British Columbia in summer 2020 where I routinely drained the battery down to 5% or less to benefit from the amazing V3 SuC speeds (yes, I saw the full 250 kW on the display). I also routinely charged the car to 100% at the hotels where I stayed. Timed it so that the car would reach 100% just when I wanted to get on the road.

Also, just for fun: IF the average max range over the lifetime of the car was just 450 km and the battery survived only 1000 cycles, I'd still get 450,000 km or about 280,000 miles out of it. And that's a rather conservative calculation. Given my driving habits that translates to 15 years of ownership. I've never kept a car that long. I'm sure they exist, but I haven't even ever seen a car that lasted that long.

That's why I'm not worried about charging to 100% when I think it would be beneficial. The only disadvantage during the first 5% or so is the reduced regen, as others pointed out.

 

[roblab]

I'll charge to 100% when leaving on any trip where my next charge will be a supercharger *if* I can time it so I leave right away when charging is complete. Just saves a bit of time and money at that first SC stop.

Whats a long trip? 500 miles or more IMHO.

... or at least one charging stop. With nearly 400 miles of range, I usually have to make a couple extra stops for bathroom breaks.

 

[3sr+buyer]

It’s the upper portion. These vehicles (SR) have a lot of regen at 100% SOC in spite of having NCA packs - this is how we know.

For capacity loss, everything just scales. There is no benefit on capacity loss to having a software-limited vehicle.

If the SR (not +) has lots of regen at a nominal 100% state-of-charge, wouldn't that mean that the usable capacity is not the upper portion?

I.e. if it is 48.1 out of 52.3 kWh (as you mention), then it would be the 0-48.1 (lower portion) or 2.1-50.2 (middle portion), not the 4.2-52.3 (upper portion), of the usable capacity to allow for lots of regen at a nominal 100% state-of-charge.

The effect of capacity loss would be as you state. But if the usable capacity is below the pack's actual 100%, then wouldn't there be less or slower capacity loss, since the pack never gets charged to its actual 100% (i.e. nominal 100% is actually 92% or 96%).

 

[3sr+buyer]

Given my driving habits that translates to 15 years of ownership. I've never kept a car that long. I'm sure they exist, but I haven't even ever seen a car that lasted that long.

Just today, I saw a 1990s Toyota Corolla and a 1960s-1970s VW Beetle.

 

[AlanSubie4Life]

wouldn't that mean that the usable capacity is not the upper portion?

Sorry for the confusion. It’s an “upper buffer” in this case, meaning the upper 8.5% or so of the battery is not usable. That’s what I meant, sorry it was not clear. I read the beginning of your question but the end of it is asking which portion is usable.

then wouldn't there be less or slower capacity loss, since the pack never gets charged to its actual 100% (i.e. nominal 100% is actually 92% or 96%).

Not significantly. Really have to be way down in SOC to slow down that loss. It would be better, but not much. Roughly speaking you could keep the SR at 8-9% higher SOC and get similar calendar loss.

Kind of off topic from original post at this point I guess. In any case for trips the 100% charging is no big deal if you use it right away. But usually no reason to do those 100% charges if you aren’t using public charging.

 

[Silicon Desert]

Elon Musk said the recommendation not to charge to 100% is because the regenerative braking can't refill an already full battery, so the car is actually less efficient when fully charged.

That's not the reason he said it. That's more of a side-effect of charging to 100%. The real reason is to maintain better battery health by not doing it regularly.

 

[ucmndd]

This is such an overwrought topic.

Charge to 100% whenever you need to or want to. Don’t let it sit at that charge longer than necessary. Go on with your life.

140,000 miles over 5.5 years, I’ve charged my car to 100% easily a hundred times. Maybe double that.

Just drive.

 

[Big Dog]

Elon Musk said the recommendation not to charge to 100% is because the regenerative braking can't refill an already full battery, so the car is actually less efficient when fully charged.

But it seems there is some concern that charging to 100% is harmful to the battery. Has this been documented by Tesla? Is Elon just doing his foot-mouth-Twitter thing again? Or are both things true?

View attachment 816988

True about Regen, but then hitting 60+ mph for a few miles gets Regen to return pretty fast.

 

[valem]

I want to know what people and even Tesla categorizes as a "long trip."
I'm asking this because of all the back and forth about what you're supposed to charge your battery to..etc etc.
I do not have one of the new LFP packs, so I've been following the guidelines of only charging to around 80% as my daily behavior.

However, all advice says that you can charge to 100% only when you have a long trip. I'm wondering what that means? I regularly drive to another city that I live 2 hours from. I usually will charge to 100% and arrive in that city at around 56-48% depending on the weather. However, I'm thinking this trip is techincally not "long enough" to justify the 100% charge.

Is a "long trip" then something that would require a visit to a Supercharger before I would arrive at my final destination or do trips that ALMOST drain the battery (arrive at <20%) constitute a "long trip?"

If you arrive with 48% then I would not consider it a long trip.
You for sure would have to charge to get back so...
You could easily charge to 80% and arrive with 28% which is perfectly fine and it would charge back to 80% faster from 28% than back to 100% from 48%.
If you want extra peace of mind, then 90% to 38% instead.

For me, if you're only using 50% range, it wouldn't justify a charge to 100%.
I would only charge to 100% to avoid arriving with single digit % left.

 

[valem]

This is such an overwrought topic.

Charge to 100% whenever you need to or want to. Don’t let it sit at that charge longer than necessary. Go on with your life.

140,000 miles over 5.5 years, I’ve charged my car to 100% easily a hundred times. Maybe double that.

Just drive.

I have actually never charged to 100%
Usually 70-80% sometimes 90% extremely rarely to 95%

 

[Lindenwood]

As an example, I intend to charge to 100% tonight. I will be driving about 80 miles to a museum, then another 10 or so to a hotel, and then another 100ish to a Supercharger. ABRP says I’ll arrive to the supercharger at around 17% battery, and “passing maneuvers” do take a few percent extra. It will probably lose another few percent overnight and preconditioning the cabin in the morning, so I expect to arrive around 10%.

Otherwise, as stated early on in this thread, it literally takes 1-2 minutes on a Supercharger to make up a 10% charge deficit so there is little benefit to charging to full unless it genuinely prevents an extra charging stop.

 

[ucmndd]

I have actually never charged to 100%
Usually 70-80% sometimes 90% extremely rarely to 95%

… Cool?

I assure you there’s no award for this.

 

[ucmndd]

Otherwise, as stated early on in this thread, it literally takes 1-2 minutes on a Supercharger to make up a 10% charge deficit

Even at full-tilt 250kw in ideal conditions, that’s a bit of an exaggeration.

 

[valem]

… Cool?

I assure you there’s no award for this.

I don't have a need to do it.
Why should I?
What is the benefit?
I lived with an 84mi (downwind/downhill) Leaf before the 75D so I can manage range pretty efficiently, and 95% or 100% really doesn't make any significant difference.

 

[Lindenwood]

Even at full-tilt 250kw in ideal conditions, that’s a bit of an exaggeration.

A bit, sure, but I regularly go 10-50% in 10 minutes so…maybe 3 minutes? In any case, especially given the ~5 minutes of overhead to/from the charger off the highway, the point still stands that if you are going to run out of battery before reaching the 2nd charger along your route, charging to 100% overnight is probably worth it. (Unless the stress of charging to 100% exceeds the stress of an additional charging stop).

 

[KenC]

Even at full-tilt 250kw in ideal conditions, that’s a bit of an exaggeration.

Is it? I've never charged for such a short time, but doing the math, it seems close enough, that I get the gist of his point. 2mins at 250kw, is about 8kw, right? That's 10% for my car.

 

[ucmndd]

Is it? I've never charged for such a short time, but doing the math, it seems close enough, that I get the gist of his point. 2mins at 250kw, is about 8kw, right? That's 10% for my car.

Yeah, I guess so. My mind is stuck in “old model S” mode - 10% in 2 minutes seems like absolute sorcery to me in any case.

 

[SomeJoe7777]

Don't worry so much about when to charge to 100%, just do it such that the battery doesn't SIT at 100% for very long.

I charge to 100% anytime I'm going to do a trip where:

1. There will be at least one supercharger stop somewhere on the round trip.
2. Charging to 100% cuts the number of charging stops down by 1, including a trip where there would have only been one charging stop but with a 100% charge it becomes no charging stops.

Set up your Scheduled Departure to finish charging the battery and precondition the car about 15 minutes before you're going to leave. If you have time-of-use lower rates, set the off-peak times properly and the preconditioning for 15 minutes before you leave. I try not to let the car sit more than 1 hour at 100% charge.

You have the capacity -- use it if it makes the trip faster, that's what it's there for.

 

[Lindenwood]

Also, to be fair, I do love some extra overhead so I can enjoy myself a bit more along the way. Practically speaking, if I could charge to 90 and arrive at my destination with a comfortable 25%, I would probably still charge to 100% to enjoy the extra oomph.

It never gets old how easy it is to *ahem* pass slower drivers without disturbing your sleeping passengers .