What should my ideal charge percentage be?

[mknox]

The easiest way to determine if 100% SOC in a new 60 is really 100% or 80% .....

Back in early 2103 I knew someone who bought a 40 kWh car and he received a software-limited 60. In his car, the charge % slider would only go so far (i.e. to about 67%) and he couldn't go past that. Later, he paid for the upgrade to unlock the full 60 (and Supercharging) and then his slider would go all the way to 100%.

Do the newer cars with software locks on the battery capacity work the same way?

 

[jerry33]

Back in early 2103 I knew someone who bought a 40 kWh car and he received a software-limited 60. In his car, the charge % slider would only go so far (i.e. to about 67%) and he couldn't go past that. Later, he paid for the upgrade to unlock the full 60 (and Supercharging) and then his slider would go all the way to 100%.

Do the newer cars with software locks on the battery capacity work the same way?

From what I've read, no. They have both Daily and Trip, just like the other models.

 

[mknox]

From what I've read, no. They have both Daily and Trip, just like the other models.

Yeah, he had that too, but "Daily" would only go from 50 to 67%. You could see the rest of the slider, right up to the 90% daily line and the "Trip" 90-100% portion, but the slider just would lock at 67% and not slide any further.

 

[Larry Hutchinson]

Yes, my previous car, an S40, would only go up part way.

My new car, an S70 which is a sw limited 75, acts like it is a real 70 and complains about daily use of 100% (which is bogus.)

 

[Ronist]

Wondering what's your opinion on this: While outside temperature is below freezing, would charging the car to 95% or higher cause permanent damage to the battery like it's in hot weather? I want to do this in order to compensate for the increased electricity consumption during the cold weather.

 

[jerry33]

Wondering what's your opinion on this: While outside temperature is below freezing, would charging the car to 95% or higher cause permanent damage to the battery like it's in hot weather? I want to do this in order to compensate for the increased electricity consumption during the cold weather.

Charging higher is not a problem if you drive it right away. Letting it sit at the extremes is the problem.

 

[Super Gizmo]

I have been charging my 2012 P85 with 50 K miles to 90% and getting 228-229 rated miles. I charge the car when it drops down to around 100-140 miles. Can't remember the last time I charged to max range. When the charging slider first appeared I started charging daily in between the Daily charging range up to 80% and my range dropped dramatically. Now it has come back up.

 

[TexasEV]

I have been charging my 2012 P85 with 50 K miles to 90% and getting 228-229 rated miles. I charge the car when it drops down to around 100-140 miles. Can't remember the last time I charged to max range. When the charging slider first appeared I started charging daily in between the Daily charging range up to 80% and my range dropped dramatically. Now it has come back up.

Your range didn't drop. It just wasn't being reported accurately.

 

[Super Gizmo]

Your range didn't drop. It just wasn't being reported accurately.

You are right. However I along with most people prefer correct range estimate from the car.

 

[mknox]

Wondering what's your opinion on this: While outside temperature is below freezing, would charging the car to 95% or higher cause permanent damage to the battery like it's in hot weather? I want to do this in order to compensate for the increased electricity consumption during the cold weather.

Back when I got my car, there were only two options (no slider): "Daily" and "Trip"

"Trip" charged to 100% and the consensus on the boards here was that "Daily" was 93%. So for quite some time, I was charging to 93% every day, summer and winter.

Charging to or near 100% seems to be worse in the heat, so I think that 95% in the cold of winter shouldn't be a problem if you need the extra capacity. It's only 2% higher than what we all used to have to charge to prior to the introduction of the slider.

 

[Super Gizmo]

the Daily tops out at 90% in my car. To get out of the car I have an Exit profile and it shows range in miles but before I drive I put it in my driving profile which shows range in %. When fully charged in Daily I show 90% in one profile and 228-229 in the other.

 

[alehbaba]

just got an s60..the service center guy said to set at 90% and plug in everyday....is that correct? Or is 70% or 80% better? i drive 50-60 miles a day max. I am in colorado and it gets cold now but some days can be 70 degrees....How should i set this slider for best battery practice? I hear elon say 80% is better for battery then 90%...yet some say 70% is best...and then i read about maybe 50% to 70% can throw a battery out of balance and then a 100% charge is needed to rebalance????geezzzzzz.....i can see tesla maybe not telling you best percent so you will need to come to them for new batteries sooner then later...i mean its possible right? But then again there must be an answer that really is the best practice right? Should i plug in every nite? Set it to finish charge right before i leave for work?? soo many opinions here.....helppppppppppppp

 

[singleview]

I charge to 90% as needed (every other day usually) and before longer trips charge to 100%.

 

[TexasEV]

just got an s60..the service center guy said to set at 90% and plug in everyday....is that correct? Or is 70% or 80% better? i drive 50-60 miles a day max. I am in colorado and it gets cold now but some days can be 70 degrees....How should i set this slider for best battery practice? I hear elon say 80% is better for battery then 90%...yet some say 70% is best...and then i read about maybe 50% to 70% can throw a battery out of balance and then a 100% charge is needed to rebalance????geezzzzzz.....i can see tesla maybe not telling you best percent so you will need to come to them for new batteries sooner then later...i mean its possible right? But then again there must be an answer that really is the best practice right? Should i plug in every nite? Set it to finish charge right before i leave for work?? soo many opinions here.....helppppppppppppp

Do what you were told-- set it for 90% and plug in every day. Charge to 100% before a trip out if town. With a 60 you don't want to worry about not having enough charge if something unexpected comes up, especially in the cold. The difference for the battery at lower charge levels than 90% is trivial.

The owners manual is very clear-- keep the car plugged in when possible (even if you don't need to charge).

I have an early 60 and keep it set at 90% except for trips 1-2/month at 100%, and plug in every night. After 4 years my range has only dropped from 208 miles to 200 miles (most of that in the first year as expected).

Don't overthink this. Enjoy your car and let the battery management system manage the battery.

 

[alehbaba]

Thanx...so setting at 80% and doing what you suggest instead of 90% will not help battery life at all? Was gonna go with the 70 but the extra $$$ seemed silly for me as i only drive under 100 miles a day if that and i have free super charging and outlet in garage...rather put the $$ to coating and bra stuff..

 

[TexasEV]

No meaningful difference for many years. If a mile or two of range makes a difference to how you use the car, you've bought the wrong car.

 

[Anjumhameed]

I think Tesla's description of the slider helps keep it simple by encouraging owners to charge to a level that gives enough range for daily use while minimizing their average SOC.




This confirms what we've already seen in battery degradation studies:

http://www.nrel.gov/docs/fy12osti/53817.pdf
http://www.cerdec.army.mil/directorates/docs/cpi/Cycled_Aged_LiIon_Cells.pdf

The calendar life of Li-Ion batteries is shortened by spending long periods of time at high temperatures and high SOC, especially both in combination. Maintaining a low SOC can protect against the effects of high temperatures, and low temperatures can protect against high SOC (which is why Tesla aggressively chills the battery during a Range charge). The US Army study shows that cycling from 0% to 50% is better for battery life than cycling from 25% to 75%, especially in warm temperatures.

The problem with recommending a "best" number is there is no one best number for everyone, only what's best for you based on how you drive your car. Range and battery health are mutually exclusive. The best setting for battery life is to keep the charge below 50%. The best setting for a >200 mile road trip is to charge to 100%. Only you know how much range you need on a daily basis. The slider gives you a tool to reduce battery degradation while still meeting your daily driving needs.

Al, if your daily driving is less than 30 miles then you're best keeping the slider at 50% and bumping it up whenever you need more range. This is how I've been running my Roadster and I have zero capacity loss after three years.

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View attachment 22239

Thanks for posting the charging screenshots. Quite helpful for many people.

 

[AZ Desert Driver]

In a parallel thread, there was a discussion as to whether to charge at 30 amps or 40 amps. Not "how full" or "how often" but "how fast".
For home charging equipment, where you have all night to fill it up, no need to stress the breakers and wires, so charge at 30 amps instead of 40 amps. Still fill to to 50% (or 90% - per comments above). Still plug it in often. Still fill to 100% on occasion. Still drain to 20 miles on occasion. Battery health is one aspect, charging health is another, daily use needs are yet another.

 

[taraquin]

I keep my SOC at 20-50% in summer and 30-70% in Winter. I have a 12 kW-charger at home so I get plenty of juice in a short time when needed. Also a supercharger 45 km away.

I still manage to get 55-56 kWh out of the battery before it says its empty, still the reserve kWs. My car is 3,5 years old now. At a full charge I get 385 km rated and 303 standard range. I believe battery-babycare is the reason However, if I didn`t have a fast charger and SC this Close I would have kept SOC higher.

 

[AZ Desert Driver]

I keep my SOC at 20-50% in summer and 30-70% in Winter. I have a 12 kW-charger at home so I get plenty of juice in a short time when needed. Also a supercharger 45 km away.

I still manage to get 55-56 kWh out of the battery before it says its empty, still the reserve kWs. My car is 3,5 years old now. At a full charge I get 385 km rated and 303 standard range. I believe battery-babycare is the reason However, if I didn`t have a fast charger and SC this Close I would have kept SOC higher.

I'm dense - I think in terms of Amps - I charge at 30 amps when I have all night, and at 40 amps from my home 240 volt 14-50 socket when in a little more of a hurry.
Now you use 12 kW - and I can't relate that to my units. Is there a nice table that shows Amps, kW for different chargers?[ I keep fouling up Ohms law]