Specify End Charging Time



Provide an option to automatically adjust the charge rate based on the charging Start and End times.


The iOS app EV ChAmp computes the lowest charge rate in amps using the number of miles in the Tesla’s batteries, target miles, Start and End Times. Software could do this same calculation and adjust the charge rate each day.

This would automatically use the LOWEST amperage charge rate for the recharging time “window” to preserve the Tesla’s batteries AND charge more efficiently.

Moderator: It’s not clear this would provide any extension of battery life or charge more efficiency. It would be beneficial to battery life if you always charge to 100% (not recommended) and time it so that you leave very soon after it reaches the 100% SOC.



(Edited by moderator)

Category: Tags: entered 23-Aug-2015


This might be useful in areas that have time-of-day electricity rates, but doesn't add value in places that have the same rates no matter what time it is.
Charging at lower amperage rates is definitely more energy efficient since less heat is lost charging at lower rates.  Just feel how hot a High Power Wall Connector connector, cable, etc. gets at 80A charge vs. recharging at 15A.  HUGE difference there plus the Tesla batteries and on-board chargers need more cooling too.

Battery life is definitely supposed to be longer using lower charge rates... Hence the Tesla recommendation to use SuperChargers sparingly for longest battery life.
I no longer use my UMC at 40A because the cable heat and reports of fires made me nervous. But it's quite slow at 30 or 32A, so I normally charge at 36A, but it would be great if I could automatically use as little amperage as I needed to get to the desired SOC within the super off peak time period.
As most users have noted, our batteries appreciate long and sloooow charge times.
This car has the very best logic ever seen in a car! So, why can't we have a user's definable end time?
Since we are told to leave the car plugged up all the time, it should know when to start charging. If I tell the car to always have this charging finished by xx:xx.
If you need to have a certain time period in which to charge, (for reasonable rates), put in your start time and let the car determine if it Can,, finish by xx:xx. Based on your amp setting and the hours available to charge, the car will "know", if it is doable. You can then adjust your beginning and or end time if needed.
Duplicate of https://teslatap.com/questions/set-stop-charge-time/
This would be too easy for Tesla to add, and remains a puzzle why people are stuck paying on-peak rates, or going back into their cars to set for TOU charging on weekends.  It is an instance where one isn't graduating to a Tesla, but descending from what just about any other EV offers.  It goes against the effort to make automation their brand.
Yes, for being able to let the car compute the charge start time so it completes when I'm scheduled to leave.

It could adjust the charge rate, I don't mind.
My Volt has this, and I miss it on my 3.  It would also help to skip or limit any morning preconditioning since everything should be warm and comfy from the recent charging.  This entry looks like it's asking for a similar feature.
Is there a source for the claim that charging more slowly is more efficient? I've read exactly the opposite. Whenever the car is charging, it has to run its battery coolant circulator pump, its inverter for the 12V systems, and potentially heat or cool the battery packs to keep them in the optimal temperature range for charging. All of that consumes energy. By charging for less time (i.e., at a higher rate), you run all those auxiliary systems less and consume less energy.

Besides, the car can supercharge at many times the rate of its on-board AC charger at max current. I really do not believe 32A at 240V (7.68 kW) is going to harm the batteries in any way.
Yes, charging at a higher kW rate IS more efficient... up to a point.  On our 2015 Tesla Model S P85D our 2st generation Tesla High Power Wall Charger ("HPWC") cable, HPWC plug and the Tesla charge port all get quite a bit hotter charging at 80A / 240V (19.2kW) than our normal 40A / 240V (14.4kW) charge rate.  Heat = Energy Loss = Less Efficient.... Plus heat is the #1 enemy of electronics and plastics lives.  We charge at 60A since it is definitely better for our 100A circuit breaker, HPWC cable, HPWC plug, Tesla charge port, and Tesla dual onboard 40A AC -> DC chargers.

And yes, charging at 32A / 240V (7.7kW) is definitely not going to harm the batteries in any way.  Repeated Supercharging and/or charging to 100% however will.