Charging Percentage

[ElectricTD]

I have purchased a 2021 X. My question is about charging percentage. I only drive about 20 to 30 miles a day. I understand the idea that Tesla has about charging whenever you are not driving. Which I plan on doing. What they do not till you is at what percentage you should charge to to keep the battery life to a maximum. I understand this would be hard to do because everyone's driving requirements are different. So I have read different threads about charging to 50% or 60% and that being the sweet spot if you only drive short distances but does anyone have any documentation or proof that this is in fact true?

 

[drtimhill]

There is very little hard data, but a lot of opinion/discussion/rumor/fiction (choose as appropriate) beyond the idea that charging fully all the time degrades the battery faster (this is well understood). I would just charge to 70% daily, 90-100% of you need it for a long trip, and not give it another thought.

 

[Les236]

There is very little hard data, but a lot of opinion/discussion/rumor/fiction (choose as appropriate) beyond the idea that charging fully all the time degrades the battery faster (this is well understood). I would just charge to 70% daily, 90-100% of you need it for a long trip, and not give it another thought.

This sums it up. Some of the M3 and MY drivers have noted doing this continually may result in calibration getting off, which then requires a few deep cycles, but this advice is sound. I also don't plug mine in every night. Sometimes going days without charging but I don't let it get below 25-30% and my scans tell me my batteries, including the 12v are doing great. Just keep it between 30-70 unless going on a trip.

 

[Teefal]

I use 80% on my Y. Seems to be consensus.

 

[DSolie]

I only charge my X when needed. I don't like to let it get below 20% if sitting, because Sentry won't work. IN the winter, I plug her in every night so I can pre-con the battery before I leave and it won't take away percentage.

 

[Fnthawar]

Someone sent me this, unsure if accurate

 

[DoctorVenkman]

This question comes up a lot and often people throw out percentages without any data to back them up. The real answer is that unless you plan to drive your vehicle significantly more than 250,000 miles it doesn't really matter if you cap it at 70%, 80%, or 90%. The difference between charge limits is negligible until you get to really high mileage - around a 1-2% difference in degradation at most. And even then you won't see almost any difference until you hit the 100,000 mile mark. This link shows actual scientific testing done that proves the impact is minimal until you get into multiple hundreds of thousands of miles driven:

https://batteryuniversity.com/index.php/learn/article/how_to_prolong_lithium_based_batteries

The only thing you absolutely want to avoid is your battery sitting close to 100% in extremely hot temperatures (i.e. 100+ F). That is what causes the most damage by far - if you live in a hot environment I would keep your battery at or below the 90% level whenever possible.

So bottom line, if you're an anal-rentive min-maxer then go ahead and cap at 60% - it won't hurt your vehicle in any way. But if you just want to set your charge limit to 90% and forget about it, you won't see any impact either until you have a couple hundred thousand miles on your vehicle.

 

[Teefal]

This is why I read these forums. Thanks Venkman.

 

[LargeHamCollider]

Someone sent me this, unsure if accurate

Any idea what the source is?

 

[Bigriver]

Some of the M3 and MY drivers have noted doing this continually may result in calibration getting off, which then requires a few deep cycles

Based on my personal data point of 1, it seems the battery management system (BMS) is pretty different between the model S/X and the model 3/Y. On my model X, the range prediction is pretty stable and predictable. The rated range decreases over time but the variation from charge to charge is fractions of a mile, regardless of what my charging behavior has been. My model 3 is much more dynamic - both decreasing and increasing by 10’s of miles in a short period of time. Many attribute that to charging and driving behavior, which may be true for that BMS.

 

[ElectricTD]

I am with you Teefal. I wanted the most accurate information and I received it. Thanks everyone for all the input.