Which way is better for the battery?

Based on what I see and learnt...I say go for Option 1

How about Option 3?
Charge to 70%, use 20% a day and charge back to 70% daily. Charge to 90% before a longer trip.

I read that Model S's used to come with a card that said something to the tune of - A plugged in Model S, is a happy Model S.

PeterK said:

How about Option 3?
Charge to 70%, use 20% a day and charge back to 70% daily. Charge to 90% before a longer trip.

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I believe there is lot of discussion on how much to charge. 70% is fine but there are lots of discussion in these forum and I believe the battery degradation is minimal if you charge to 90%

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Max* said:

I read that Model S's used to come with a card that said something to the tune of - A plugged in Model S, is a happy Model S.

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Yes absolutely but OP was wondering whether to charge daily or not..plugging the car is a must every day

I'd go with #1.

My understanding that in general, many small charges are better then fewer bigger one.

Also, you are better prepared in case something comes up unexpectedly and you need more range on that 3rd day.

PeterK said:

How about Option 3?
Charge to 70%, use 20% a day and charge back to 70% daily. Charge to 90% before a longer trip.

Click to expand...

After doing this for a while, the BMS seems to forget the true capacity. I have been charging this way mostly for the past several weeks. Today I did a range charge and it reached 100% but was still charging at 40/40 amps. This indicates the BMS reached 100% prematurely when in fact there is additional capacity it "forgot about."

PeterK said:

How about Option 3?
Charge to 70%, use 20% a day and charge back to 70% daily. Charge to 90% before a longer trip.

Click to expand...

This.

apacheguy said:

...Today I did a range charge and it reached 100% but was still charging at 40/40 amps...

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It's my understanding that when you do a range charge, the charge current may stay high and slowly taper even at/near 100%. This is to allow for what's called a 'balance charge'. The Tesla pack is made up of many hundred (thousand?) individual cells. The pack can only safely discharge until a single cell gets to the cut-off voltage. If it tried to go further, it would damage that cell and degrade the pack. It's also true that during normal 90% charges, not all cells will be up to the same charge level.. some cells will be a bit lower than others. A balance charge allows the pack's microprocessors to individually turn cells charge on/off as needed to top them all the way up.

It's important to note that Lithium cells all have a finite number of full discharge/charge cycles. Small discharges daily (and top-ups) have less impact on cell / pack health than full discharges / recharges. Further, it's bad for lithium cells to sit at 100% charge for an extended period (or especially be held there). So, I vote option 1 - Charge to 90% daily, drive for the day, recharge.

Only top that last 10% up right before a long trip (even by only increasing the charge level an hour or two before you leave), then drive it fairly soon to not leave it that high.

Hope this helps!
LK

PeterK said:

How about Option 3?
Charge to 70%, use 20% a day and charge back to 70% daily. Charge to 90% before a longer trip.

Click to expand...

Science tells us that the Liion battery stay most healthy around 50% SOC, however, on surveys here people who regularly charge to 90% seem to have better battery life than those who charge to 70 or 80%. I wonder why.

Candleflame said:

Science tells us that the Liion battery stay most healthy around 50% SOC, however, on surveys here people who regularly charge to 90% seem to have better battery life than those who charge to 70 or 80%. I wonder why.

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Yeah I wish we would get some more official advise on this, seems that way. Since I don't drive much most days, like 25-30 miles max, I've been charging to 50% only, and it probably gets down to 35-40% on most days, then plugging in and charging back to 50%. Up to 90% on longer trips, and done 100% a couple times only.

Rated range != battery capacity meter. There are various uncertainties in calculating rated range. See my post in this thread where I speculate on the "90% effect"

What's your 90%? - Page 24

I read an article recently that said a longer charging time is not as good as a shorter charging time, which might explain why shallow charge cycles are preferred to deeper cycles. I don't have the link to the article, but it was specifically regarding Li-Ion batteries. Of course, there are many different formulations and this is a general statement. The reason cited by this article was the "parasitic reaction" that takes place on the anodes in the battery cells. Parasitic reactions increase when the battery is being charged, which is why shorter charge times are better. Again, this may not be as applicable to Tesla's special battery chemistry, but thought I'd put it out there.

Candleflame said:

Science tells us that the Liion battery stay most healthy around 50% SOC, however, on surveys here people who regularly charge to 90% seem to have better battery life than those who charge to 70 or 80%. I wonder why.

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We don't know that. If you regularly charge to 90% the rated range is higher, but that's not equal to battery life, and may just be the way the algorithm works.

AmpedRealtor said:

I read an article recently that said a longer charging time is not as good as a shorter charging time, which might explain why shallow charge cycles are preferred to deeper cycles. I don't have the link to the article, but it was specifically regarding Li-Ion batteries. Of course, there are many different formulations and this is a general statement. The reason cited by this article was the "parasitic reaction" that takes place on the anodes in the battery cells. Parasitic reactions increase when the battery is being charged, which is why shorter charge times are better. Again, this may not be as applicable to Tesla's special battery chemistry, but thought I'd put it out there.

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Parasitic reaction can also be due to high charge rate, depending on cell temperature.

FWIW: I charge to 90% at all times despite the fact that I rarely use the capacity I get from charging to that level however on the rare day that I do need the range it is comforting to know that I can just get into the car and go without concerns or waiting to top off before leaving on my journey.

kort677 said:

FWIW: I charge to 90% at all times despite the fact that I rarely use the capacity I get from charging to that level however on the rare day that I do need the range it is comforting to know that I can just get into the car and go without concerns or waiting to top off before leaving on my journey.

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I do the same, only at 80%. 200 miles is three plus commutes, so there is always plenty extra, and the SCs are about 100 miles away in any direction, so that's not a concern either.

When i first got my car, there were only two choices, Standard or Max Range. Standard was around 93%, if I remember right. Once the slider update came out, I dropped my daily charge to 70%. Over time, I saw much lower rated range. My last road trip in June to Boston, I only saw 187 rated miles at 100%. Frustrating! Upon returning home, I started thinking... and decided maybe Tesla knew what it was doing initially. So I set my slider to 90%, and scheduled charging (not initially an option when my car was new, either BTW) to begin around 3am so it would finish before I leave at 6. Over the next month, I saw rated range increase 11 miles. I now see 198 at 100%. So I'm sure there had to be some pack balancing that happened. Whatever it was, I'm happy for it, since I'm making another trip to Charlotte in 2 weeks!

I have done daily charges to 90% for first 4 months, then charge every 3-4 days for the last 5 months. I have a very short commute, seemed overkill to plug in for charging from ~215 rated miles to 227. I did not see a difference in range (at either 90% or 100%). I know the owner's manual says plug in daily, but I am not sure if this applies to my particular situation. On top of that, I would imagine wear and tear on the charging port must come in play at on point in time.

Btrflyl8e said:

When i first got my car, there were only two choices, Standard or Max Range. Standard was around 93%, if I remember right. Once the slider update came out, I dropped my daily charge to 70%. Over time, I saw much lower rated range. My last road trip in June to Boston, I only saw 187 rated miles at 100%. Frustrating! Upon returning home, I started thinking... and decided maybe Tesla knew what it was doing initially. So I set my slider to 90%, and scheduled charging (not initially an option when my car was new, either BTW) to begin around 3am so it would finish before I leave at 6. Over the next month, I saw rated range increase 11 miles. I now see 198 at 100%. So I'm sure there had to be some pack balancing that happened. Whatever it was, I'm happy for it, since I'm making another trip to Charlotte in 2 weeks!

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Yes Tesla added the slider because they realized there is a good amount of people who don't need 90% capacity every day so allowing the slider to be set lower would help those people keep their battery healthy. New features help and improve things!

The fact that the rated range drops when only partially charging and discharging the battery has been explained by Tesla. It's due to inaccurate calculations, it's not actually capacity loss. Seeing your range drop when only charging to 70% or something similar, is not a sign of a decaying battery. Tesla has also explained why doing a few full cycles brings the rated range estimate up again. Again it is not regained capacity. It is due to a more accurate capacity calculation after a full cycle.

It's a well known fact that lithium batteries age quicker at higher state of charge. Charging only as much as you need has a positive effect on the battery. That's why Tesla added the slider allowing you to go as low as 50.