Increasing battery longevity.

[leodoggie]

I am going to buy my model y so battery longevity has become very important.
I designed and built my own 12 Kw battery backup system using lifepo4 batteries. With those batteries if you cycle between 25% and 75% soc you can increase cycle life x4. There is a lot of data to support the fourfold increase, so I was wondering if anyone has any data for li ion batteries that Tesla use in this regard?

 

[kkillebrew]

Can of worms. I think what you stated is pretty close to the Tesla standard, although Elon says he charges daily to 90%. Staying between 25% and 75% is okay for city driving, but on the road it will kill your range as you are only using 50% of it's capacity.

 

[ewoodrick]

Tesla batteries are indeed slightly different.
For the Model 3, the lifetime of the car is currently running at about 300,000 miles. It was anticipated that the Model Y may be at 1,000,000 miles, similar to the Semi.
Tesla's battery handling techniques are significantly more advanced than your battery backup solution and, most importantly, the usage of a car is very different.

In short, don't worry about them.
Charge to 80-90% and life will be happy.
If you are going on a trip, charge to 100%

 

[leodoggie]

Can of worms. I think what you stated is pretty close to the Tesla standard, although Elon says he charges daily to 90%. Staying between 25% and 75% is okay for city driving, but on the road it will kill your range as you are only using 50% of it's capacity.

Thanks for the post, I have been driving an ev for about three years so I am experienced in long distance driving and how to fast charge for maximum range.
What I am hoping is to get data on how to get maximum battery longevity with home charging.

 

[leodoggie]

Tesla batteries are indeed slightly different.
For the Model 3, the lifetime of the car is currently running at about 300,000 miles. It was anticipated that the Model Y may be at 1,000,000 miles, similar to the Semi.
Tesla's battery handling techniques are significantly more advanced than your battery backup solution and, most importantly, the usage of a car is very different.

In short, don't worry about them.
Charge to 80-90% and life will be happy.
If you are going on a trip, charge to 100%

If your 300,000 mile or 1,000,000 mile figures are correct then battery longevity is not an issue, good to know, thanks.

 

[aronth5]

Thanks for the post, I have been driving an ev for about three years so I am experienced in long distance driving and how to fast charge for maximum range.
What I am hoping is to get data on how to get maximum battery longevity with home charging.

There are countless threads on this and various opinions but I would venture to say no definitive answer. Leodoggie says it well
"In short, don't worry about them.
Charge to 80-90% and life will be happy.
If you are going on a trip, charge to 100%"

And I would add what Tesla always says- "a happy battery is a plugged in battery"!

 

[eevee-fan]

Regardless of how advanced Tesla batteries are, Li-ion battery is most happy at 50%. Higher % and it increases cell stress.

My recommendation... charge up to the level so in the morning, you are 50% + 1/2 day's commute, so that you end the day with 50% - 1/2 of day's commute. So if you use 20%, start the day with 60% and come home at 40%.

When you need longer range, charge to higher SOC, up to 100% if going on a long trip.

Just my 2 cents. Not a Tesla battery expert, but seems to be what I see on general info on Li-ion batteries.

 

[bchan911]

There are countless threads on this and various opinions but I would venture to say no definitive answer. Leodoggie says it well
"In short, don't worry about them.
Charge to 80-90% and life will be happy.
If you are going on a trip, charge to 100%"

And I would add what Tesla always says- "a happy battery is a plugged in battery"!

I would have to incline to agree with you. I recently got spooked about supercharging throttle and the effects of supercharging on battery life, as I don't have any charging options in my loft and rely on the supercharger network. Did some research and scoured posts for real experiences with people abusing their Tesla's and have concluded that you really shouldn't obsess over it. Pretty sure Elon himself said in a tweet that charging to 90% is fine.

However, what really impressed me was that an Arizona Model 3 with 160km, recently shared his account of an approx 2 year abuse of supercharging daily to 100%. The battery has only suffered 8.62% degradation based on the the 523km rated range and has not experienced any throttling on the supercharging network. Tesla Joy exclusively supercharges to 90% biweekly has experienced 0% degradation after 1.5+ year ownership based on her original 502km rated range. She also doesn't have a charger at home.

Tesla's software and new batteries are far superior than what were previously made in the older model S's and X's and we're really just obsessing over nothing. I reference supercharging here a lot because it's the worse case scenario with a high rate of charge and high heat, which is what is supposedly "damaging the battery." I think charging to whatever makes you feel better about your car is fine and home charging slowly via AC is even better. And "life will be happy" as @ewoodrick says.

Cheers!

 

[ewoodrick]

Regardless of how advanced Tesla batteries are, Li-ion battery is most happy at 50%. Higher % and it increases cell stress.

My recommendation... charge up to the level so in the morning, you are 50% + 1/2 day's commute, so that you end the day with 50% - 1/2 of day's commute. So if you use 20%, start the day with 60% and come home at 40%.

When you need longer range, charge to higher SOC, up to 100% if going on a long trip.

Just my 2 cents. Not a Tesla battery expert, but seems to be what I see on general info on Li-ion batteries.

While this may be the case from one aspect of battery maintenance, it's not the only. It's also one at which the batteries don't get a chance to equalize.

 

[Saghost]

There are a bunch of threads on this topic, with some divergence of opinion.

It’s pretty well established that cycles with both ends closer to fifty percent are less wearing on Lithium chemistries than cycles closer to the ends.

A lot of discussion is around how much difference it makes for these particular batteries and how much more you lose by going further to the ends.

There are other things that degrade the batteries - time at higher temperatures while at higher states of charge is a bigger one, which is what bit Nissan so badly on the Leaf.

There are also other factors to consider beyond battery health. Most of the middle range of state of charge for most Lithium chemistries is at a constant voltage, so the car relies on a math model of energy in and out of the pack to determine where in the middle it is - made more complex by the chemical capacity of the battery changing with temperature and over time.

That’s why Tesla recommends charging to 90% - it’s slightly over the constant voltage region, so the car gets a clear understanding of the actual state of charge of each cell block.

There are documented cases of the car algorithms getting confused when they haven’t seen either the upper or lower voltage ranges for a while and showing less range - and then getting the lost range back after seeing both ends.

So there’s a lot going on, and reasons for various approaches. I mostly charge to 80%, but I try to get to 90% every few weeks so it knows that end. I only get into the bottom half on road trips, and that will have to be enough. Fortunately, I like road trips.

 

[eevee-fan]

There are documented cases of the car algorithms getting confused when they haven’t seen either the upper or lower voltage ranges for a while and showing less range - and then getting the lost range back after seeing both ends.

So there’s a lot going on, and reasons for various approaches. I mostly charge to 80%, but I try to get to 90% every few weeks so it knows that end. I only get into the bottom half on road trips, and that will have to be enough. Fortunately, I like road trips.

Correct, that's why if you know your morning SOC %, evening SOC %, and KWh used for overnight charging, you get a pretty good idea if you GOM is off.

Yep, it is also a good idea to take a long trip every few months, thus giving you the change to charge up to 90% or 100% to allow for cell rebalancing.

 

[ratsbew]

If you want ultimate battery life, use a 60% daily charge limit and cycle it between 40% and 60%. The BMS might become "uncalibrated", but that is just a measurement issue, not actual pack degradation.

 

[SSedan]

To those diehard believers stop and think about what 85kw pack owners were saying a year ago. It was the same as what is said here.

That was before Tesla decided to cap range 10-15miles lower and lower supercharging rate 40%, and raise Regen threshold temps.............all those parameters were fine from 2012-2019 and then suddenly changed without explaination.

I sincerely hope the positive outlooks shared here pan out..........but we don't KNOW that yet. What we do know is Tesla got spooked a year ago and handicapped a lot of cars without explaination.
Maybe it is battery lot numbers that were failure prone or some other measured metric in service. Honestly though my money is on they were too aggressive with the battery parameters and don't want to admit it.

 

[Ctuna]

Battery charging question. I charge to 90 percent for my windsurfing trips out to San Luis Res and back . Start out with 300 miles range and get back with about 70 to 75 miles of range in the evening which is something like a 25 percent charge . I can's start charging till 12 pm to get the EV rate . Am I better off for battery longevity to wait to charge at home the next day or vist a super charger and put
a little charge or charge back to mid range and wait till the next day to top off at home. At home if I have nothing planned I would charger to 75 to 80 percent the next day. (Model Y Long Range Tesla Wall Charger at 48 amps)
If staying around town I could go for several days and still be around 60 percent charge.

 

[jcanoe]

If you don't need to drive many miles once you return home, before you can charge at home starting at 12 pm the next day and benefit from the off-peak rate then waiting would be the best option. Leaving Sentry mode active when parked at home for 12 hours would use ~3 % of the remaining battery charge. The battery is not stressed by remaining at a low state of charge; just the opposite.

Supercharging, unless you have Supercharger credits, will be more expensive than your off-peak rate, possibly more expensive than your peak rate. Supercharging, while it will not damage the battery, does subject the battery to much higher charging rates than Level 2 charging at home, etc. You would also need to put a cost on your time spent driving to and from the Supercharger, charging when you could be at home doing other things.

Level 2 charging during the off-peak time, at home, would be the least expensive, least stressful for the battery. Since you can charge at home as needed you may want to charge 55%, daily, instead of 80% several times a week and determine if that meets your local driving needs.

 

[Ctuna]

Peak Rate under the PGE ev plan is something like 52 cents a kilowatt last time
(and now like 20 cents /kw during off peak Cali has expensive electricity)
I looked, which is about 7 cents / kw more than than tesla chargers during peak hours. Also I have banked Solar power. Recurrent says the range to keep it in is between 30 and 80 percent for max battery longevity . Logically it would seem leaving it lower would be less stress to a point. I wonder what Tesla says about leaving it in a low state of charge for short periods of time? They say that when your traveling to go down to about 20 percent for the fastest charging rate.

 

[ewoodrick]

Peak Rate under the PGE ev plan is something like 52 cents a kilowatt last time
(and now like 20 cents /kw during off peak Cali has expensive electricity)
I looked, which is about 7 cents / kw more than than tesla chargers during peak hours. Also I have banked Solar power. Recurrent says the range to keep it in is between 30 and 80 percent for max battery longevity . Logically it would seem leaving it lower would be less stress to a point. I wonder what Tesla says about leaving it in a low state of charge for short periods of time? They say that when your traveling to go down to about 20 percent for the fastest charging rate.

Tesla says don't go to 0 because it may damage onboard electronics.


Yup, that's about it.

There's the camp that say keep it at 40%, there's the camp that follows Tesla's guidance and I've yet to see any usuable data from the 40% camp on just how long the battery life is extended.

In other words, Tesla built the battery to last. They built it to take most any crap that you want to throw at it.

Charge as fits YOUR lifestyle.

And when road tripping and went to maximize charge rates, you want to go well below 20%. Go plug into a 250kW station and plot your charge times from 10-20-30-40%-etc. The 250kw station will be over 1000mph rate up to around maybe 40%. Then it's down to the equivalent of 150kW station at 500mph until about 70% at which time it starts to slow down below 200mph.

Charging from 5% to 40% happen about as quick as 40 to 60%!

Stop worrying about the battery, Tesla is doing that for you.

Charge as fits YOUR lifestyle.

 

[jcanoe]

25% is no problem while parked until the next day at noon unless you suddenly have to drive some longer distance. The only downside; when the state of charge falls below 20% then Sentry mode and Cabin Overheat protection are automatically disabled to conserve the remaining charge in the battery.

 

[Ctuna]

model Y and 3 are using the 2170 battery's . Pansonic has done at least one
upgrade that got the LR pack up to 84 they where suppose to be doing more
although now they may be distracted and working on the LFP and LMFP stuff
plus there own 4680.
The 2170 packs are replacable as module's maybe there will be and upgrade in the future although by that time Salt battery's maybe the thing.

I disable the Sentry mode at home and never have active cabin cooling on so far this year the external temp has not been over 80 and that is a rare day hear on the coast of California so far.
I wonder how much leaving Sentry mode and active cabin cooling actually takes
as far as kw per hour?
Cabin temp can measure way high on a Sunny day even if the external temp is below 70 . When I get in it doesn't seem as hot as it reads on the App.
I think there is something wrong with the placement of that sensor.

 

[Mrbrock]

Battery charging question. I charge to 90 percent for my windsurfing trips out to San Luis Res and back . Start out with 300 miles range and get back with about 70 to 75 miles of range in the evening which is something like a 25 percent charge . I can's start charging till 12 pm to get the EV rate . Am I better off for battery longevity to wait to charge at home the next day or vist a super charger and put
a little charge or charge back to mid range and wait till the next day to top off at home. At home if I have nothing planned I would charger to 75 to 80 percent the next day. (Model Y Long Range Tesla Wall Charger at 48 amps)
If staying around town I could go for several days and still be around 60 percent charge.

You mean 12 am right? Off peak EV is 12am to 3pm. You will be just fine with the car sitting at 25% for a few hours.