Best way to precondition / Charge for retired people

[Tam]

Tam: I have a home charger. None of my trips uses over 20% of my battery. Are you saying that to strictly follow the manual, I’d charge to 100% every day even if I have a 95% SOC?

Correct. That is what the instruction says.

My battery would never get below 80% SOC.

Correct. If you follow the manual, your scenario will never reach 80% SOC.

Have you even looked at the data for LFP batteries and how to lessen calendar aging.

I’ll follow @AAEE. I’ve seen the data he’s posted. Until Tesla actually posts data on the effect of never discharging a LFP battery below 80% and it’s impact on calendar aging and BMS calibration, I’ll go with the science posted on this forum.

I know some talks about keeping SOC low is good for your battery, but that is not the practice instructed by the manual.

I would instead follow the manual rather than the science not covered by the manual.

So, the question and confusion for this thread is:

Is the manual wrong to instruct to charge LFP at 100% SOC all the time?

Since it is wrong, should I follow AAEE instead?

 

[bruce4000]

To me leaving your car plugged in does not mean charge to 100% everyday but it allows the BMS to get power as needed. From what I have read, both LFP and Nickel L-ion batteries degrade more when left sitting over 90% but LFP less so. The thing with LFP is that its voltage vs state of charge is not very linear so harder for the BMS to tell what the state of charge is. So that’s why you would charge it to 100% once a week or so but otherwise, I would charge only to no more than 80% depending on your needs. If road-tripping then 100%.

 

[RickCRNA]

OP….I don’t think you are going to find a definitive answer to your inquiry using this forum. To many differing opinions and to much toxic attitude. You may want to contact Tesla directly with your question and describe your situation and concerns.

Rick

 

[AAKEE]

Until Tesla actually posts data on the effect of never discharging a LFP battery below 80% and it’s impact on calendar aging and BMS calibration, I’ll go with the science posted on this forum.

Discharge is not needed for lithium batteries in general, so you will be good.

Only thing to remember is that even if LFP’s can do many many cycles, they are affectedf by calendar aging. They will degrade from that at about the same rate as the other chemistrys or slightly less.

From what I have read, both LFP and Nickel L-ion batteries degrade more when left sitting over 90% but LFP less so.

From 75-100%, the calendar aging is virtually the same.
In many researches the highest degradation is around 80%, so keeping it at 80-90% will not reduce degradation.
This research shows a quite flat line above 70-100%.

The technical/chemistry reason for that the defradstion is lower below about 70% is the central graphite peak, it is located at about 72% true SOC.
Teslas use of buffer offsets the displayed SOC so 70% or below is good.

I would charge only to no more than 80% depending on your needs. If road-tripping then 100%.

Choosing 80% would not be the best solution. It will not reduce degradation and it will not help the BMS keeping track of the SOC either.

Stay at 70% or below if the idea is to reduce calendar aging.
Charge full if more than 70% is needed.

I would go 70% most days and 100% once a week. The 100% charge would be charged just before the drive and before the longest drive during the week.

 

[eevee-fan]

If you only drive about 1 charge (272 miles) in a month and most miles are from road trips that is done every month or two, what's the best strategy?

 

[jjrandorin]

If you only drive about 1 charge (272 miles) in a month and most miles are from road trips that is done every month or two, what's the best strategy?

There is no version of the question "how should I charge?" that hasnt already been asked at least 5 times on TMC. This question is basically "how should I store my car when I am not driving it?, Which has been asked dozens of times.

The answer has not changed, which is "Plug it in, set it to 50%, and charge it before your trip".