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Charging to 100% in the morning and leave at night

max35111

Member
Jan 27, 2015
81
1
geneva
Guys, here is probably a usual situation for model S owners.

I know it's not good to leave your car charged at 100% for some time but how to manage the situation where you can only charge at home and consequently be at 100% in the morning but your roadtrip starts at 6pm after work and you need the full battery.

So basically drive off in the morning at 100%, drive 5 miles and leave the car all day long at 98/99%? Is it real bad?
 

mwulff

Member
Jan 15, 2015
348
25
Danmark
Short answer: YES, it is real bad.

Long answer it will cause buildup of graphite material in your anodes in the battery pack and significantly shorten battery life. Maybe use a bike to work and leave the Tesla plugged in at home until you need it and start the charging via the app or scheduled charging.
 

MartinAustin

Active Member
Jul 21, 2013
2,774
12,223
Austin, Texas USA
Well, you're only supposed to charge to 90% if you're going to leave it for a while before driving it.

Can you charge it to 90%, leave the cable connected, and then, if you really need it at 100% at 6pm, turn on the charging again at 5:30pm? (or whatever the right time would be) You could control it with your cellphone.
 

max35111

Member
Jan 27, 2015
81
1
geneva
Unfo I can't because I don't have charging at my work parking! Guess I would need to leave it at home to do that and come back home afterwork, which won't be very convenient!:-(
 

hiroshiy

Supporting Member
Supporting Member
Apr 6, 2013
2,407
2,004
Tokyo, Japan
I have the opposite situation to Max35111. I have a HPWC at work and no charging at home due to condo. When taking roadtrip on Saturdays, I usually charge to 100% at work on Friday, and drive home a few miles. Then the car sits there for like 12 hours.
 

max35111

Member
Jan 27, 2015
81
1
geneva
I have the opposite situation to Max35111. I have a HPWC at work and no charging at home due to condo. When taking roadtrip on Saturdays, I usually charge to 100% at work on Friday, and drive home a few miles. Then the car sits there for like 12 hours.

Thanks hiroshiy! I guess it's no big deal if it's left like that 5/6 times a year!
 

chetalien

Member
Sep 3, 2015
33
0
UK
I dont think its good idea to keep it charged 100% all the time.
Secondly you can leave it unplugged and it shouldnt really matter- as per TESLA advisers.
 

max35111

Member
Jan 27, 2015
81
1
geneva
That's actually the question: does it matter to charge to 100%, unplug in the morning, and let it sit at that unplugged all day long basically
 

David_Cary

Active Member
Dec 17, 2012
1,240
779
Cary, NC
One big issue is what temp will it be at?

Is it a big deal - not really. To the battery obsessed (myself included), I would try to minimize the situation. You could Uber to work but I probably wouldn't go that far. Can you charge to 97% and be just fine? then you would site at 95% for the day which would be better.

Now Hiroshy is playing with fire - basically doing what you are worrying once, 50 times a year. But it may not matter all that much. He is in a cool climate (as are you - Geneva Switzerland?).

The Leaf (different battery and BMS I know) has not shown significant degradation increase at 100% but what we aren't sure of is Tesla's 100% closer to 100 than Nissan's? The forums are pretty sure Nissan's 100% is about 96% - I can't remember why they know that.
 

max35111

Member
Jan 27, 2015
81
1
geneva
I am in Geneva indeed!
Thanks for your input, looks like the best solution is to take the motorbike to work on Friday, then bike home on Friday night and leave from there. This situation where I need the full charge won't be at every roadtrip so should be alright.

Temp of the car would be around 18 degrees in work parking.
What is acceptable %age for the car to sit at? 90?
 

scaesare

Well-Known Member
Mar 14, 2013
8,534
14,726
NoVA
On occasion when you need to do a road trip?

Nah.

I, as a result of a mixup, inadvertently had the car charge to 100% one Saturday night, and didn't notice it until Monday morning. It sat that way for ~36 hours , and it was summertime heat in my garage.

No change in my observed ranges for the pack after.

As mentioned above, the 100% setting on the car is slightly below the full-charge voltage each cell is rated for.

I wouldn't do it every day for months on end.... but I wouldn't hesitate to do it when needed for a road trip either.
 

FlasherZ

Sig Model S + Sig Model X + Model 3 Resv
Jun 21, 2012
7,028
1,017
Don't worry about it if it's only a handful of times.

I don't worry about it at all. My car has 62,500 miles (43k on the battery) and still charges to 265 miles (down from 266). I have let the car sit at 100% charge for 1-2 days occasionally, whenever it needs to be (or if I've forgotten to set it back to 90%). In June, we took a road trip to Florida and all we had was a 120V outlet at the condo we stayed at, so I always left it at 100% charge so that I could gain as much as possible without having to head off to the supercharger for a top-up (especially since Turkey Lake SC is on a toll road).

Bottom line: don't abuse it by leaving it on 100% all day, every day; use it when needed but don't fret about it. I've seen suggestions that you need to try and time the charge perfectly so that you leave within 10 minutes of it hitting 100% - that would never work in my household. If we're leaving at 4 pm for a road trip, I don't worry about setting it to 100% at 7 am.
 

hiroshiy

Supporting Member
Supporting Member
Apr 6, 2013
2,407
2,004
Tokyo, Japan
One big issue is what temp will it be at?

Is it a big deal - not really. To the battery obsessed (myself included), I would try to minimize the situation. You could Uber to work but I probably wouldn't go that far. Can you charge to 97% and be just fine? then you would site at 95% for the day which would be better.

Now Hiroshy is playing with fire - basically doing what you are worrying once, 50 times a year. But it may not matter all that much. He is in a cool climate (as are you - Geneva Switzerland?).

The Leaf (different battery and BMS I know) has not shown significant degradation increase at 100% but what we aren't sure of is Tesla's 100% closer to 100 than Nissan's? The forums are pretty sure Nissan's 100% is about 96% - I can't remember why they know that.

BTW I'm not doing that every Saturday - I do that only when necessary ; once in two months or so. Will try to choose 99% or 98% instead.
 

Rockster

Active Member
Oct 22, 2013
3,012
4,621
McKinney, TX
OP, I know you say you need the full battery but do you really need the full battery? Could you possibly charge to 95% or 98% and make up the difference by driving more conservatively for the first portion of your trip?
 

smartypnz

Supporting Member
Supporting Member
Jan 23, 2013
2,170
2,339
Monterey Peninsula
Tough one! In your situation (and location), I would do the 90% and, if possible charge for 30 minutes right before departure at one of the many CHAdeMO chargers available in your area. Then again, if you can use a CHAdeMO, you can charge anywhere or anytime on your trip to make up the needed distance.. Check the CHAdeMO website map for all the locations.
 

AmpedRealtor

Well-Known Member
Jun 30, 2013
6,414
3,399
Phoenix, AZ
Short answer: YES, it is real bad.

There is no evidence to support this. While it seems to be well established that charging to 100% isn't so bad on its own, there is differing opinion on how long the car has to be at a high SOC in order for the higher level to actually be "bad". In fact, some Tesla service centers were recommending that owners keep their batteries at 100% SOC for several days in order to re-balance and regain some displayed range.

Bottom line: We don't know how long a car has to sit at 100% in order to accelerate long term degradation, but it's likely that one day isn't going to have a meaningful impact on anything.

Maybe use a bike to work and leave the Tesla plugged in at home until you need it and start the charging via the app or scheduled charging.

I'm not trying to single you out, but saying it's preferable to ride a bicycle than to leave your car at 100% SOC for a day doesn't make much sense to me.
 

max35111

Member
Jan 27, 2015
81
1
geneva
Thanks for your inputs guys. I have to say I don't like the idea of having such a nice and expensive car that's supposed to replace an ICE road trip car making me biking to the office to make sure it is properly charge!

Don't take me wrong I would do it if needed but rather use it as it has the least amount of drawbacks!

The trip to the first charger is 74,5kw from evtripplaner so I guess I need the full range! Any difference btw charged 100% or 98% for the battery?
 

max35111

Member
Jan 27, 2015
81
1
geneva
Regarding the question f charging on the way, I could stop for few mins at a supercharger but would require 30 mins detour all in + 15 mins charging!

In normal circumstances I wouldn't mind that much but we are awaited for dinner on that night and don't want to arrive later than needed!
 

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