Charge to 100% - Do U Really Need To?

[IvesSM]

I see many discussions on charging before a trip to charge to 100% but I ask, is it really necessary?

On a trip do u really need 100% charge to make it to your first Supercharge? I would say no. So why would you charge to 100% in the first place?

Charging to 100% is only going to effect the first leg of your trip. After that your Supercharging the rest of the trip.

My daily charge is to 80% and I might move that up to 90% before a trip but never to 100%, you just don't need that SOC to get to your first Supercharger stop.

Of course this does not apply to those TESLAS that require you to charge to 100% each time you charge because of their unique batteries.

I'm curious what others think.

-stew

 

[NewbyMaybe]

Full charges during a trip will result in fewer charging stops. Overnight charging to full is better than super.

 

[ewoodrick]

Should you, not if you don't need to. Can you, absolutely.

There are many routes that I've been that if I top the car off, I can skip what would have been my first charger.
It ends up being (if I charge to 100% before leaving each direction) that one direction I charge at stops 2,4,6,8 and the way back I charge at 7,5,3,1.


And don't forget that in most cases, you don't want to stop at your first Supercharger, you want to get the car down to 10-20% to allow for faster charging.
And that first stetch is often when I feel best, so I'm good for driving a little longer.

 

[SilentWarp]

I see many discussions on charging before a trip to charge to 100% but I ask, is it really necessary?

On a trip do u really need 100% charge to make it to your first Supercharge? I would say no. So why would you charge to 100% in the first place?

Charging to 100% is only going to effect the first leg of your trip. After that your Supercharging the rest of the trip.

My daily charge is to 80% and I might move that up to 90% before a trip but never to 100%, you just don't need that SOC to get to your first Supercharger stop.

Of course this does not apply to those TESLAS that require you to charge to 100% each time you charge because of their unique batteries.

I'm curious what others think.

-stew

Agreed. Besides the degradation hit, on long trips, you should only charge enough to get to next charger (+ a bit more) because charging a battery in the first half is quicker than filling up the second half -- You will spend less total time charging and get to final destination quicker. The question is what is a "+ a bit more". I guess it depends on supercharger redundancy coverage in the states you are travelling though along the way.

 

[DCGOO]

I see many discussions on charging before a trip to charge to 100% but I ask, is it really necessary?
On a trip do u really need 100% charge to make it to your first Supercharge? I would say no. So why would you charge to 100% in the first place?
Charging to 100% is only going to effect the first leg of your trip. After that your Supercharging the rest of the trip.
My daily charge is to 80% and I might move that up to 90% before a trip but never to 100%, you just don't need that SOC to get to your first Supercharger stop.
Of course this does not apply to those TESLAS that require you to charge to 100% each time you charge because of their unique batteries.
I'm curious what others think.
-stew

It totally depends on what you are paying. I pay 2.1¢ per kWh to charge at home. Supercharger typically around 35¢ per kWh. So any kWh I can add at home saves money. When I had a 2018 with free supercharging, it was completely reversed.

 

[ucmndd]

Charge to 100% whenever you want.

Or not.

Seriously, do whatever you want. If you’re terrified of unspecified “battery damage” so much that you don’t want to start off a road trip with as much energy as possible, then don’t.

The rest of us will charge to 100% whenever we feel like it and never give it a second thought.

 

[IvesSM]

It totally depends on what you are paying. I pay 2.1¢ per kWh to charge at home...

Wow, that's some dirt cheap electricity. The best I can do here is 10 cents per kw for generation and 5 cents per kw for delivery. Total 15 cents per kw.

In your 2.1 cents calculation do you have solar or did you forget to include both the generation and delivery in your calculations?

 

[E90alex]

Let me turn the question back around on you and ask is it really necessary for you to daily charge to 80%? How much do you really use in a day?

 

[DCGOO]

Wow, that's some dirt cheap electricity. The best I can do here is 10 cents per kw for generation and 5 cents per kw for delivery. Total 15 cents per kw.
In your 2.1 cents calculation do you have solar or did you forget to include both the generation and delivery in your calculations?

No solar. It is a special rate for EVs, off-peak, that requires a separate service entrance and meter to access it. Normally, I pay just under 12¢ per kWh, flat rate.

 

[IvesSM]

Let me turn the question back around on you and ask is it really necessary for you to daily charge to 80%? How much do you really use in a day?

E90alex - thanks for your reply.

We have 2 TESLAS. 1 with 3 yr free Supercharging and the other is charged @ home.

The free supercharge car goes to the supercharger about once a week and charges to 80%. The home charging car gets plugged in when my wife gets home after her day and is generally down to 30-40% SOC and gets charged back to 80%. The home charging happens about 2-3 times per week. Our rate is about 0.16 cents per kw which includes generation and delivery charges.

We are lucky here in PA. We get to shop for our electric provider so we can go with the lowest bidder and depending on the plan, switch without penalty whenever we like. It just takes a bit of time to evaluate all your options and clicking to switch.

Over the years we have saved over $3k in electric charges by switching to a cheaper supplier.

Let me throw the question back to you E90alex. What do u do and pay for electric?

-stew

 

[NewbyMaybe]

If the wife's car were charged to 90% and charged every other day then the fewer cycles would be better for the pack.

 

[ewoodrick]

If the wife's car were charged to 90% and charged every other day then the fewer cycles would be better for the pack.

That's not really the right definition of cycle. AFAIK

 

[DCGOO]

Wow, that's some dirt cheap electricity. The best I can do here is 10 cents per kw for generation and 5 cents per kw for delivery. Total 15 cents per kw.
In your 2.1 cents calculation do you have solar or did you forget to include both the generation and delivery in your calculations?

We do not have separate generation and delivery available, everything in the same bucket. Slight correction, I pay 2.331¢ per kWh off peak in the summer, but that is for everything, plus a couple of taxes, but very minor. Over the last 31days, I've spent a total of $12 for our Model X and our Model 3 combined, roughly 1,000 miles driven on each. Now that is using a separate service entrance with its own meter, but the bill is combined. The service can only be used to charge our EVs. The rest of our usage runs around 12¢ per kWh, flat rate, no ToU plans available for residential users. The utility only serves our little city, of about one million.

 

[IvesSM]

Wow, you've got great rates. What state is this?

 

[E90alex]

If the wife's car were charged to 90% and charged every other day then the fewer cycles would be better for the pack.

No, smaller charges are better for the pack.

 

[dafish]

OP:

There are those that think nothing of higher SoC. I'm not gonna dive into that can of religion, but I can tell you those that have looked deeply into the science of this typically charge below 70%. Plenty of threads on that, I'd just search. User Akee (I think I got that right) has quite a few very well informed posts. Personaly I L2 charge to 55% at all times, with trips handled just as Silentwarp, who is exactly correct, has advised.

I can also say If I was going to charge to a relatively higher level it would be done just before use.

 

[DCGOO]

If the wife's car were charged to 90% and charged every other day then the fewer cycles would be better for the pack.

Actually a “cycle” is a full charge to empty. I’d go with Tesla’s recommendation, leave the car plugged in unless you are driving it. Many small charges are easier on the battery, than few charges going from empty to full. Superchargers are even harder on the battery, save those for road trips.

 

[ewoodrick]

Actually a “cycle” is a full charge to empty. I’d go with Tesla’s recommendation, leave the car plugged in unless you are driving it. Many small charges are easier on the battery, than few charges going from empty to full. Superchargers are even harder on the battery, save those for road trips.

But the cars with the most mile on them ONLY charger at Superchargers.
Tesla has made Supercharging nearly a non-event for the batteries by being aggressive with battery conditioning before and during charging.

 

[ewoodrick]

Agreed. Besides the degradation hit, on long trips, you should only charge enough to get to next charger (+ a bit more) because charging a battery in the first half is quicker than filling up the second half -- You will spend less total time charging and get to final destination quicker. The question is what is a "+ a bit more". I guess it depends on supercharger redundancy coverage in the states you are travelling though along the way.

While I agree with a good portion of this, the thing that gets left out is the time that you lose getting off the road.
If you try to stay between 5% and 60%, I think that you optimize time a little better.

 

[GSP]

Agreed. Besides the degradation hit, on long trips, you should only charge enough to get to next charger (+ a bit more) because charging a battery in the first half is quicker than filling up the second half -- You will spend less total time charging and get to final destination quicker. The question is what is a "+ a bit more". I guess it depends on supercharger redundancy coverage in the states you are travelling though along the way.

This is best for the battery, AFAIK. However, is the battery the most important thing, or is convenient road tripping more important to the reader?

I would never "charge only enough to get to the next charger" since it makes no sense to interrupt my lunch to go unplug and move the car before I finish. I will do that to avoid idle fees, but otherwise I will let it supercharge to 100%. When I get back to the car, I will unplug and leave immediately, with some extra charge that allows me to make only a short bathroom break at the next supercharger. Same for the bathroom break. I will walk to the bathroom, take care of business, walk back, unplug and go. I will have more charge than needed. I will not stop the charge when I have "just enough to get to the next charger."

The point I am trying to make is to plan trips around your schedule, not the battery's schedule. Plan your stops to be at superchargers, plug in while you are there, unplug and move on. This is the best way to road trip in an EV, IMO.

GSP

PS. In the super rare occasion that I am ready to go before the car is, then of course I will unplug and leave as soon as I have enough charge to get to the next stop (with 10-20% reserve). This has only happened to me twice in 7 years of road trips. Both times I ate at a restaurant that did not have a supercharger nearby, and my wait time was only about 10 minutes.