Welcome to Tesla Motors Club
Discuss Tesla's Model S, Model 3, Model X, Model Y, Cybertruck, Roadster and More.
Register

Draining close to empty

This site may earn commission on affiliate links.
Is it bad to run the battery down close to empty all the time?

On ICE, I'm used to driving until the red light is on for awhile and using an EV I usually drive until I'm down to <20 miles range left on the Tesla and <10 miles range in other EVs (e.g. Leaf, etc.).

Is it bad to run it down that low? I don't run it to empty but usually the car is complaining about low charge, etc.

On the other end, I charge up to 80% or 90% only and never up to 100%.
 
Are you charging at home? If so, there really isn't much sense in letting the battery run down. If you are not, I suppose there could be some convenience in running it down, but it isn't particularly healthy.

If I recall correctly, it's best for the battery pack health to keep it at or above 20% on the low end.
 
  • Helpful
Reactions: IdaX
It seems like the idea of draining came from the old NiMH operation and the user has not evolved to the more modern chemistry that does not have Memory.
Now, if I was in the market for a used car, how could I tell if the battery was abused? What price penalty should apply here?
 
fwiw, i charge up to around 90% and then drive off immediately and it's always at 264 miles (I have a MX 100D). I haven't noticed any decline since I got the car (roughly 7000 miles in right now).

i charge at home sometimes but mostly charge out at urban chargers while i'm on the road.
 
So this shows how the battery operates on its TOP. Would its bottom look the same?
I'm not quite sure what this bottom mean. The full pack is the full pack energy when charged to 100%, but the BMS can estimated when not charge to full. On the other end, when draining the pack to 0%, then there will be zero.

However, another parameter to look at is the internal resistance, the smaller the better.
 
So if I understand the above....when shopping for a used Tesla, take the car to a charger and fill it to 100%. Note how many miles the full pack reflects. Compare that to what a new pack should be. Divide A by B and see how much degradation has happened. If that number is better than 90%, don't discount for abused battery. If the number is 70% - choose another car. At 80%, assume the car has been abused but not ruined and discount by How Much?
 
So if I understand the above....when shopping for a used Tesla, take the car to a charger and fill it to 100%. Note how many miles the full pack reflects. Compare that to what a new pack should be. Divide A by B and see how much degradation has happened. If that number is better than 90%, don't discount for abused battery. If the number is 70% - choose another car. At 80%, assume the car has been abused but not ruined and discount by How Much?
Yes. And the "normal" value can be found here. You can select mileage or age to see of it is above the average or below.