That is time-efficient not energy-efficient. Unless stated otherwise "efficiency" is energy based.
I drove my first electric - 2025 BMW i4 M50
- Thread starter alarmguy
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Disagree. Most readers understood my posts were all concerned with travel time efficiency; that's pretty easy to infer. Several posts in this thread were discussing charging strategies affecting travel time, specifically charging the new BMW to 100% on a public charger.
For maximizing efficiency on EV road trips, consider using the 20-80% rule for charging and charge to destination to minimize total travel charging time.
Optimizing for speed and charging habits can significantly reduce overall travel time.
In my case it is also cost efficient. I charge at home with that big nuclear reactor up in the sky. Very cost efficient.
EV efficiency, or ICE efficiency for that matter, is a broad topic.
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That statement does not automatically bracket "efficiency" as a matter of time.
20%-80% is terribly inefficient with time. 20%-60% is better. In fact it is a mistake to worry about the top SOC number at all, the fastest way from here to there is to charge only what is needed to safely make the next charging stop. That is what Tesla navigation will do.
Likewise, one might very well get there faster driving 65 MPH than 83 MPH. Spend less time charging in the higher SOC range. Spend less time charging. "Totally New Concept!"
I know how to drive an EV and I know why the navigation plan works the way it does. It's all about SOC, location and destination. I'm just explaining to you that "efficiency" has a lot of categories in response to your earlier post. And there are a number of factors within the given categories; your example is one.
When I charge on the road, I basically charge to destination, which is generally to home. But I am not strict; if I am waiting in line at Starbucks, a few more charging minutes is not big deal. Just a little more money. I don't sweat the small stuff.
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As a retired engineer I spent a lot of my career explaining efficiency to those of weak technical comprehension.
When one says, "charging efficiency" one is not talking about time.
Disagree; let me explain. Time is a direct result of charging efficiency.
Efficiency is the quality of being able to do a task successfully, without wasting time or energy.
EV charging efficiency refers to how effectively the energy from a power source (like the electrical grid) is transferred to and stored in the electric vehicle's battery.
Higher EV charging efficiency means less energy is wasted, enabling faster charging times, lower electricity cost, and potentially more.
Your posts are all over the map; I am not sure why.
No it is not. And you go on proving my point:
Yes, how much power applied stays in the battery vs how much is converted to heat.
Not at all. At higher SOC the charger deliberately reduces the applied current to protect the cells, minimizing wear. Has nothing to do with power staying in the cell vs conversion to heat.
Because of your lack of understanding. You seem to think charging slows as the battery fills because the battery can not charge faster. It can charge that fast, but then you would be buying a new EV battery every couple years.
Charging slows as the battery fills for no other reason than to extend the service life of the battery. Hey! Liberal interpretation of "efficiency" can apply here! More efficient having a 20 year battery than a 2 year battery! But that is quite a stretch of "efficiency" that no one would infer without convoluted reasoning. Just as "charging efficiency" does not mean "time".
Sorry Jeff, but you are all over the map on this one.
There are different ways to measure efficiency. If you’re talking about energy efficiency, as in the amount put in vs the amount taken in by the battery, that doesn’t take time into the equation.
You simply cannot correlate energy efficiency with time, which you are trying to do.
Now, if we’re talking how much charge a particular battery takes in over a fixed amount of time, that would be called charging rate, not efficiency.
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Disagree. The more efficient the charging, the shorter charging dwell time.
OVERKILL
$100 Site Donor 2021
I feel like Jeff is trying to talk about time or route management efficiency, but lumping in "charging efficiency" as if it has a time component, which is screwing things up.
In terms of time management (which is what the car optimizes for in its charge planning), the most efficient strategy employs the mechanism @GrumpyCat describes, only adding enough charge to get to the destination (with buffer), minimizing the amount of time spent at chargers. This has no relation to the efficiency of the charging process, as you two have pointed out.
This discussion was based on @alarmguy BMW charging strategy which I suggest results in a longer trip time than necessary.
What I would add to @OVERKILL post is, there are more components to travel, such as eating. If you are stopping for an hour, multitasking by charging may overall shorten your travel time. That's an efficient charging strategy.
What I would add to @OVERKILL post is, there are more components to travel, such as eating. If you are stopping for an hour, multitasking by charging may overall shorten your travel time. That's an efficient charging strategy.
Fair enough, but it has nothing to do with efficiency, but time management.
But now I see that your use of the term “efficiency” simply comes from corporate operations where this term applies to optimizing tasks or processes which for the most part translates to time savings.
In the engineering world, it has a totally different meaning, especially when talking about the transfer of energy.
4WD
$50 site donor 2025
I drive past a Tesla charger group - next to 3 large restaurants - next to a medical complex - always looks efficient to me 
This is why EVs are specific to the user. Some people enjoy the trip without stopping. Eating is NOT a common component to everyone while driving.
Also if stopping for an hour means not having to deviate from your trip it is well worth it if you can stop at a renowned place, loved by many, even for the fun of stopping there some people make the trip stop.
How much time would you save by going to some tiny backwards place? nothing and how much fun would you have? Maybe none.
Many uses for EVs not everyone falls into a specific category in the way they use their EV. Many in here seem to not want to acknowledge that individual users choice, even if they have no knowledge of where they are stopping for that hour/
I hear the same old stuff from them all the time. Not sure why? Making comments on something they have never experienced at a Buc-ee's and its on the same exact road they you are traveling.
I seen one suggestion in here, that was mapped out from someone, that showed stopping at a GM dealership for a quick charge (lots of fun there*LOL*). Then later on to another backwoods place (tiny town), instead of a 1 hr to full charge world class stop that most people in the USA except the southeast and Texas have any knowledge of. It's like armchair commenting from the people who say, enjoy the stop!!!
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Oh yeah, stopping at Buc-ee’s is always a good experience IMO. You can easily take 30 minutes in there. An hour isn’t much of a stretch if you start browsing a little.
I seen one suggestion in here, that was mapped out from someone, that showed stopping at a GM dealership for a quick charge (lots of fun there*LOL*). Then later on to another backwoods place (tiny town), instead of a 1 hr to full charge world class stop that most people in the USA except the southeast and Texas have any knowledge of. It's like armchair commenting from the people who say, enjoy the stop!!!
The stops were based on computing fastest trip time, and in an EV there are numerous variables that go into where and when one stops in pursuit of fastest trip time.
The fastest trip, and the "funnest" (is that a word ?) trip are often mutually exclusive.
If it were me, I'd plan a bit of time for fun and that always means stopping at a Buc-ee's if one is on the route.
The Midwest version of these were the Little Americas on the 80.
The lower class West Coast version is called Terrible Herbst.
One might notice Buc-ee's doesn't have any tables or chairs.
4WD
$50 site donor 2025
Or take the BBQ sandwiches/drinks back to the EV … Kidneys happy too …
Yes and all these posts in here are mentioning if he made two stops to no name places, off the road he was traveling, didn’t fully charge, he would have got to my house 20/25 minutes earlier. Arriving with less charge no less and start off the next day looking to charge again instead of a care free ride 85 mile trip back to Buc-ee’s which you also know has the latest full functioning super chargers that are always available.
If I’m driving 83 MPH on the interstates which is a blast. Like my son I would rather stop once on the road/exit that I have to exit to where I know the latest great super chargers, at a place with two dozen of them so no waiting or wondering while visiting a world class travel stop.
I guess I’m missing something here coming from the group that is saying charging is no big deal.
Bottom line it takes longer traveling with an electric, as much as an hour added to his four hour trip or as little as 4 hours and 40 minutes if you do it “thier” way. I guess I’m just thick headed.
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