Welcome to Tesla Motors Club
Discuss Tesla's Model S, Model 3, Model X, Model Y, Cybertruck, Roadster and More.
Register

What should my ideal charge percentage be?

This site may earn commission on affiliate links.
agreed.
Most of my days I'll drive fewer than 50 miles.
The problem is that some of the long drive days are unpredictable. All of a sudden you find out that your friend can't use his center court tickets to a playoff basketball game, and you don't want to have to say, "gee I'd love to use them, but unfortunately my car won't get me there because I only charged to 50% last night".

I'll gladly pay a mile or two of range a year for the peace of mind of knowing that on any day I can go anywhere I need to go.

If that's not worth it to you, I guess it's great that they've got the new feature, but for me, the old way was simpler.

I don't understand why it matters to you. The default is 90%. What's easier than not changing it? If you don't want to change it, don't change it. I don't understand why you want to force everybody else not to be able to change it.
 
I don't understand why it matters to you. The default is 90%. What's easier than not changing it? If you don't want to change it, don't change it. I don't understand why you want to force everybody else not to be able to change it.

It doesn't much matter to me. I will set it to 90% and mostly forget about it.

Did I say that I wanted to force everybody else not to be able to change it?

If that was my implication, I should have been clearer.

Here's what I should have said:
1) The new feature does not help me.
2) Assuming that charging to 90% only costs a mile or two per year compared to charging at 50%, I think most users would be better served charging to 90%
3) The new feature adds complexity for users.
4) This complexity comes with a small psychological toll on users: do you want to be good to your battery or do you want to be able to drive anywhere you want any day of the week. The simpler system removed that question.

In general, I'm in favor of adding choices, and I often grate at Apple's "We know how it should be done, and thus it will be done" philosophy.

I don't really care that Tesla added a choice here, but I do think they made things harder on themselves by adding it. Now people will have questions about what to set the charge level to.
I'm certainly not going to refuse to update just because 4.5 adds this choice.
 
I'm quite excited about this new option, for exactly this reason. I don't want to replace my battery if I don't have to, for both financial and environmental reasons. For 99% of our driving, we won't need more than a 50% charge. To be able to get that while extending battery life makes me a happy camper.

Perhaps in the future they'll need to offer both settings methods. Default can be the "Basic Mode" (which includes the old Standard/Max toggle) and then an "Advanced Mode" (with the new % slider) that you can enable, just for us geeks.

I agree. We are a bit of a special case, since we live on an island that is about 16 miles end-to-end! Because we have to deal with ferries, we almost ALWAYS know when we are going "off island." The rest of the time, we will happily keep the slider at 50%.

In a sense, we all live on islands. If your routine is well-worn, you know your needs and limits. If you are the super spontaneous "let's get married in Vegas" type, charging to 90% is probably still your best bet. :wink:
 
  • Like
Reactions: MaryAnning3
After reading this thread it seems I should be charging to 50%, but can't do that yet without 4.5 and am worried about the days where I'll suddenly need to drive farther and won't have charged to 90%. Hopefully the app lets me change the %.

You are not locked into any one percentage from the looks of it. You could drop that number to 70 or 80% if that provided a better buffer for unexpected trips.
 
You can absolutely control your charge duration by installing a 50 Amp, 70 Amp, whatever, (2 or 3 pole) contactor in series with your present charging scheme. This contactor will be controlled by a hand-wound spring timer of appropriate maximum duration: one hour, three hours, etc. Drivers who know precisely how many KWHs they will need tomorrow can dial in the exact minutes accordingly. Then contactor will click OFF at 2:45 hours and ModelS will be disconnected from mains for the rest of the night. No worries about software, firmware, 'over'charging the traction battery, etc. You can sleep easy, empowered.

Disclaimer: Thou shalt obtain approvals, inspections, specificities of all and sundry sorts from all required & imagined experts deemed likely to impinge on your happy home and its proper operation. Just sayin'.
--
 
You can absolutely control your charge duration by installing a 50 Amp, 70 Amp, whatever, (2 or 3 pole) contactor in series with your present charging scheme. This contactor will be controlled by a hand-wound spring timer of appropriate maximum duration: one hour, three hours, etc. Drivers who know precisely how many KWHs they will need tomorrow can dial in the exact minutes accordingly. Then contactor will click OFF at 2:45 hours and ModelS will be disconnected from mains for the rest of the night. No worries about software, firmware, 'over'charging the traction battery, etc. You can sleep easy, empowered.

Disclaimer: Thou shalt obtain approvals, inspections, specificities of all and sundry sorts from all required & imagined experts deemed likely to impinge on your happy home and its proper operation. Just sayin'.
--

I have to chuckle at the idea of a $100K car with advanced battery design, multiple on board computers, an API to allow web-services based access, mobile-device integration, etc... being charged by manually-wound "spring" timer.
 
  • Funny
Reactions: cleverscreenam
Well, after all the discussion about maximizing battery life in normal operation and the new 4.5 release, I wanted to point out that the battery charge level control is awesome for VACATION mode or extended storage of any kind. Any battery life improvements likely in normal day-to-day operations (where the car is discharged part of the day) will be multiplied in a storage scenario. It's best to keep a stored battery on the charger, but it's also best to maintain a lower SOC -- this update accomplishes that perfectly in a way that was relatively hard to achieve before now.

Freekin' YAY.
 
> being charged by manually-wound "spring" timer. [scasaere]

The spring-wound timer, GE brand ~$25-US, for example, @ any hardware store, has a low-power 120 volt switch that is designed to control a much larger switch, i.e. the 50A contactor. So all you see on the wall is a small cover plate and a single rotary knob. You turn the knob from 12 o'clock to 6 to run the load for half the total switch time. For charging a Tesla you probably want a switch with max time of 6 hours (just a guess) and this may have to be special ordered. It is a trivial task to replace the spring switch with one of a different duration, should you so desire (and possess the ~simple skill set). Or, and this might be the 'beauty part', you can have two or more different timers mounted on the wall- just turn the one you want.

I've been using this system on my 30A water heater for over a year now. Water heater is ON only ~3 hours per week average, OFF for the remaining 165 hours. $aves mucho KWHs for use in the Teslas.
--
 
  • Love
Reactions: cleverscreenam
agreed.
Most of my days I'll drive fewer than 50 miles.
The problem is that some of the long drive days are unpredictable. All of a sudden you find out that your friend can't use his center court tickets to a playoff basketball game, and you don't want to have to say, "gee I'd love to use them, but unfortunately my car won't get me there because I only charged to 50% last night".

I'll gladly pay a mile or two of range a year for the peace of mind of knowing that on any day I can go anywhere I need to go.

If that's not worth it to you, I guess it's great that they've got the new feature, but for me, the old way was simpler.


this is what i'm screamin....
 
...
3) The new feature adds complexity for users.
4) This complexity comes with a small psychological toll on users: do you want to be good to your battery or do you want to be able to drive anywhere you want any day of the week. The simpler system removed that question.... I do think they made things harder on themselves by adding it. Now people will have questions about what to set the charge level to.....


Having been on on these boards and others for six years I can say there is a post every month or so with a new owner of any EV asking about how to maximize the range of their car's battery.

Some confused souls suffer self imposed range anxiety because they read the warnings to not charge full because of reduced battery life. They must be thinking just one range charge will catastrophically degrade their battery to a triple A output.

On the other end of the spectrum I know at least one owner that always charges in range mode. Battery be dammed.

All I am saying is that many people learning battery care will be confused at the beginning of ownership Adding a slider will probably not increase that count by much.
 
  • Informative
Reactions: Vern Padgett
Well, after all the discussion about maximizing battery life in normal operation and the new 4.5 release, I wanted to point out that the battery charge level control is awesome for VACATION mode or extended storage of any kind. Any battery life improvements likely in normal day-to-day operations (where the car is discharged part of the day) will be multiplied in a storage scenario. It's best to keep a stored battery on the charger, but it's also best to maintain a lower SOC -- this update accomplishes that perfectly in a way that was relatively hard to achieve before now.

Freekin' YAY.

Definitely. For normal usage I'm not too worried about normal 90% charge, but I believe 75% is still more than I would ever need without knowing ahead of time, so why not. However in June I'll be away for 4 weeks, so I certainly hope I get 4.5 before then to be able to set it to 50% for the time that I'm gone.
 
I'm quite excited about this new option, for exactly this reason. I don't want to replace my battery if I don't have to, for both financial and environmental reasons. For 99% of our driving, we won't need more than a 50% charge. To be able to get that while extending battery life makes me a happy camper.

Perhaps in the future they'll need to offer both settings methods. Default can be the "Basic Mode" (which includes the old Standard/Max toggle) and then an "Advanced Mode" (with the new % slider) that you can enable, just for us geeks.


Totally agree and I'm excited too. Apparently the science says the number is 50%. This is where I will set my slider. I'm glad to have the option and once again kudos to TM for giving us this option. I understand the arguments about confusing the "average" customer but also think this is easily explained/remedied with something like the solution above.
 
Anyone know why 4.5 isn't being rolled out? If it's already in multiple production cars, you'd think they could start rolling it out to the masses.

So far it's only in the 40kWh cars, and they have it because the slider is used to limit the charge to 40kWh on a 60kWh battery.

Standard Mode and Range Mode aren't needed on the 40kWh models and I'm sure Tesla saw an opportunity to implement Storage Mode, variable capped Standard Mode, Range Mode and a 40kWh limit all with one single simple control.

This also explains why the daily range on the screenshots only goes to 72% - the 40s are locked out of the top end of the range. As a side benefit they don't need to worry about capacity loss.

Tesla is probably still testing the firmware with the 60 and 85 versions.
 
Set my battery to 50% anyone else using that setting? Figured since my wife has such a small commute 130 rated miles rated should be more than enough and help extend battery life.

Any thoughts on those settings? I saw there was a driving setting I believe was 70% to 90% that was marked on the battery pic.

ken