Ideal charge %?

[HaulingAss]

Just out of curiosity, if the Cybertruck battery is actually 4 packlets, aren't we always charging the same 2 packlets to 100%, if we're home-charging to 50% every day?

I actually spoke to a Tesla engineer in person about this back in January and he speculated this same problem. Only the level 4 superchargers truly charge all the packlets in parallel, where each would be charged to XX% instead of a few being charged to 100% and the remaining getting a residual charge

No. All cells in the entire pack are charged and discharged equally, regardless of the voltage of the charger.

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[HaulingAss]

The data points don't align for the below 50% club. Here is why. It moves people away from EV's when we need to move to them. People read this nonsense, and they start thinking. Crap if I can only charge to 50% I will stick with gas.

I don't trust the Swedish fella over on TMC. His data is from Battery University, and all slides have publisher removed. We don't do that in the science world.

All I can say is I have many a Tesla miles. Many than most, but not all. I choose convenience over battery longevity. Yet don't overcharge to say one can drive what one never drives. Be smart about it. Yet not so smart you can't get out of Dodge when one really needs to get out of Dodge. Been burned twice on situations like that. It wasn't fun. So just think about that prior to joining the 50% or less club.

I can go through each car and it's degradation, but they are very similar yet somewhat better than what Tesla publishes for long term cars.

Exactly! The ideal charge percentage is the amount you need to do what you do and have a reasonable reserve for contingencies. Naturally, if there are Superchargers in the areas you drive your need for emergency reserve is less (because you can always plug in for 5 minutes or whatever you need) and if you travel over large distances with no Superchargers your need for contingency range will be greater. It will be different for each use case.

Don't sweat it, just enjoy that it doesn't need gas.

 

[mcm4ss]

don't we have a million mile battery? or some shit like that. I remember it was something like 100k. So, compared to a ICE rig and just having to dump 21k into one for a motor I would say I am totally confused as to which one is better still if you are going to talk about such stuff. However I love the driving experience of the EV so much I really don't give a $$#@. LOVE this truck. Everyone wants to ride in it. I get 100k out of it I will feel like a winner when or if I have to replace my batteries. Besides, maybe by then we will have that dry cell flat polymer aluminum battery I keep hearing about.

 

[SentinelOne]

I charge to 100% daily in case i have to race a lambo on my commute! ?

actually based on my commute of either 10 or 100 high speed freeway miles i keep mine at 65% and just up it if i know i need more! Wish wall charger would do 80 amps at home to offer a bit faster charging/ flexibility and id prob leave charge percentage a bit lower.

 

[Nice2CTu]

I'm not taking sides on "optimal" charging % because, as several have pointed out, depends on weather, parking in climate control, range of driving needed (hospital, bar, back to hospital), etc.

However, would like to contribute to discussion by including the charge curve as a factor. Tesla says that the CT can charge 35% in 15 minutes. My calculation differs somewhat but let's go with that. If you are charging at home with a 14-50 (42 Amp 240 volt), it takes about 16 hours to get to 100%. 35% x a Telsa 320 mile battery range means you can get 1/3 of 320 miles in 15 minutes. So you could make the trip theoretically with 3 charges (1 every 100 miles) @ 15 minutes, or do a 16 hour chagre for the whole trip.

THe above is a little off topic but for local driving, in my case I have a daily 50-mile round trip commute. A colleague has the same, but driving a Model 3 and he charges from a 120v outlet, so he barely can charge enough in a day, but catches up on the weekend and lets it run down until the weekend.

Personally I like the 50% cap on charging (160 miles gives me 3-day cushion on my commute), and I've read/reviewed the Out of Spec and Sandy's team's battery reviews, my conclusion is the 35-50% is optimal for battery life if you can get away with it, but would never worry about an 80% cap either if that's what makes me sleep better. And there are a lot of other considerations...EVs get better mileage in city driving because of regen charging vs. Freeway driving, temperatures, etc.

 

[Jager]

There's probably more misinformation about EV pack health/degradation than all other EV characteristics combined. For anyone interested, there are numerous scientific, peer-reviewed studies out there that cut through owner (experience inevitably based upon small sample size) and manufacturer (corporate priorities do not always align with their customers) bias.

The good news is that Tesla's BMS is very sophisticated. And their packs are quite robust.
They will withstand a surprising amount of hard use.

But for those who wish to optimize their battery health...

Lower SOC is better
Lower temps are better*
Shallower charge cycles are better
Lower charge rates are better

*except for charging. Lithium plating is probably the worst thing we can do to a lithium chemistry battery, and the risk of that phenomenon increases greatly as temperatures fall towards freezing. Tesla's BMS will mostly protect against this.

 

[jimnycricket65]

80% is the highest recommended value for daily charging.

For battery longevity you can charge to a lower % that you're comfortable with. I find with the larger battery of the Cybertruck (compared to the Model S and Model X that I owned previously) that charging to 70% daily gives me plenty of available range. 70% x 123 kwh battery = 86.1 kwh x 3 mi/kwh actual efficiency = 258 miles of real-world daily range available.

I'll probably trim back to 60-65% for daily charging since if I'm driving 200+ miles in a day I usually know in advance. Worst case is I make a quick 10 min pit stop at a Supercharger.

The other part of this is to schedule your charging, ideally during off-peak hours with a set departure time if you have a regular schedule. For me I aim to have it finish charging by 8am daily so it typically doesn't start charging until 3-4am. Net result? The average state of charge the batteries sit at is lower for a longer period of time as it's just topping up for the day before I unplug and take off. Also helps to warm the batteries during those cold NJ winters aiding efficiency.

I like this but I am not comfortable starting the day below 80% and the thing is I don't drive regularly and the lowest I have seen after a day is 50% - beastmode.

 

[jimnycricket65]

the 50% thing basically comes from the idea that the lower the state of charge the battery is kept at, the more cycles it can undergo without significant degradation. There was a graph i read somewhere a while ago that describe the ideal SOC of a Li Ion battery is something like 30-70% daily, the study found that batteries that were kept in that SOC range could undergo many many more cycles without significant degradation.

tesla has put a whole lot of resources into Battery Management, and so they have determined that if your goal is to achieve maximum longevity from the battery, but also maximize useful range, the best balance between the two is 80%

if you only drive like 100 miles a day however, you can further increase battery longevity (cycles before significant degradation) by keeping the battery at a lower SOC range.

hope this helps.

hmmmm....80% is recommended but the lower % is "better" on the battery. This gives me the idea then, to charge about what I need the following day.

 

[Wonderful]

I'm not a long time Tesla owner, my daily commute eats about 6% so I only charge once a week to 80% then use it until 20% or so then do it again. Kind of like my cell phone. Charge it at night, use it until low or the next night.

 

[carsly]

I like this but I am not comfortable starting the day below 80% and the thing is I don't drive regularly and the lowest I have seen after a day is 50% - beastmode.

I was in the same boat. For my other Teslas (X, S) I always had them charging to 80% as they typically underperformed EPA range estimates. After a week or two with Cybertruck I took a chance and adjusted down to 70% and it's been more than ample for my needs. Occasionally I need more range and then charge to 80% or even 90%, once. Keep in mind the battery is much larger than other Teslas and I find my real-world efficiency is within a hair of what I was getting with my Model S Plaid on 21's.

As I've gotten more and more comfortable at 70%, which provides over 250 miles of real-world range on my AWD in Sport mode, I'm thinking of dropping down to 60-65%. YMMV, go with what works for you but I will say that Cybertruck seems to handily outperform EPA range estimates in my two months and 1,500+ miles of driving.

 

[CyberGus]

I'm not a long time Tesla owner, my daily commute eats about 6% so I only charge once a week to 80% then use it until 20% or so then do it again. Kind of like my cell phone. Charge it at night, use it until low or the next night.

The "best practice" is to charge daily to the lowest percentage you'll need for the next day. Of course, I don't know your situation or your ease of plugging-in.

I specifically had a pedestal installed next to my parking spot, so plugging/unplugging is a 5-second task. Many of the other Teslas I see in my neighborhood run the cable under the garage door when they charge, so it's less convenient.

 

[Wonderful]

The "best practice" is to charge daily to the lowest percentage you'll need for the next day. Of course, I don't know your situation or your ease of plugging-in.

I specifically had a pedestal installed next to my parking spot, so plugging/unplugging is a 5-second task. Many of the other Teslas I see in my neighborhood run the cable under the garage door when they charge, so it's less convenient.

Still using an outlet to charge and Tesla superchargers near my home. I will get the Power share installed soon and my plan would be to keep it around 60-80%

 

[HaulingAss]

There's probably more misinformation about EV pack health/degradation than all other EV characteristics combined. For anyone interested, there are numerous scientific, peer-reviewed studies out there that cut through owner (experience inevitably based upon small sample size) and manufacturer (corporate priorities do not always align with their customers) bias.

Not really. All of the peer reviewed studies I've seen available were done on batteries considerably different than Cybertruck batteries. Different physical construction, different chemical composition. Even a different thermal management system can dramatically alter the results. All the studies I've seen were done in a lab, without liquid cooling/heating. There's no point in claiming the study must be correct when it was testing a completely different battery that weren't thermally managed in the same way. Over the years battery chemistry has been tweaked in many ways to change the degradation characteristics, amongst other things.

The good news is that Tesla's BMS is very sophisticated. And their packs are quite robust.
They will withstand a surprising amount of hard use.

But for those who wish to optimize their battery health...

Lower SOC is better
Lower temps are better*
Shallower charge cycles are better
Lower charge rates are better

*except for charging. Lithium plating is probably the worst thing we can do to a lithium chemistry battery, and the risk of that phenomenon increases greatly as temperatures fall towards freezing. Tesla's BMS will mostly protect against this.

We can only speak in generalities since there is not any extensive data on the degradation characteristics of the chemistry and form factor used in the current generation 4680's. Yes, Tesla has reams of data that they use to program the BMS and guide customers, but they do not share the actual data. I trust their guidance because not only do they know more about the cells used in Cybertruck than anyone in the world, they also are on the hook for 8 years/120,000 miles for any failures.

I would caution against people thinking lower charge rates are better because previous generation batteries (the ones we have actual data on) like to be pretty warm when charging. Any Level 2 charge rate is not too high for battery longevity, it's just trickle charging. And if the battery temperature is below 70 degrees, more power available, up to the maximum Cybertruck Level 2 charge rate of 48 amps, is going to be beneficial. The more, the better. Not only because it will build a tiny bit of beneficial heat inside the cells as it charges, but also because it gives the BMS more power to work with to heat the battery if it's cold or cool it if it's too warm. The active heating is pretty hard to implement if all the BMS has to work with 15 or 20 amps at 120V and you expect the battery to charge from cold.

One of the most misguided pieces of advice I see surrounding battery degradation is to always charge at the lowest rate that will complete your charging before you need to depart. Complete hogwash! In weather below 70F, I would suggest it's probably beneficial to charge at the full 240V and 48 amps that the Cybertruck is capable of. ANd the cooler it is, the more this is true.

But people spend far too much time fretting over this, just give the EV plenty of power to work with and let the BMS handle temperature regulation and rate of charge. If the battery is frozen, you can give it 48 amps but the BMS will not send 48 amps to the battery because that would cause increased degradation.

We don't drive Nissan Leafs (that don't even have a real thermal management system for the batteries) so let the BMS worry about it. The worst thing you can do is not give the BMS enough power to work with.

 

[CHC]

I charge to 90% every day. I didn’t buy the truck to baby it and agonize over degradation all day. If the battery degrades a meager 10% over 10 years, so be it.

 

[Outdoors]

Always remember that when we use the words we think. Those words mean we don't really know. Very expensive words. So unless one works for Tesla, and sees the numbers. Like the ones they publish each year on longevity of batteries. I don't take half baked 15 year old data off the Internet.

The worse thing ever for a Tesla is for it not to be driven. All those good things in life need to enjoyed not fretted over.

I guess I could charge all the Tesla's to 35%, and then run back home each time to pick up the next one at 35%. That seems foolish.

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