Caution area on regenerative zone of the energy app

[Zextraterrestrial]

In winter 2013 I asked why there wasn't always a regen limit shown even though the car was clearly regen limited and I was told that there are many variables in the algorithm besides temperature.....made me really want to know all of the variables

I think the car doesn't quite know precisely how much the battery resistance has increased due to the cold temperature until it asks the battery to output its peak power(or more than the battery can currently output). The car has an idea of how much more resistance there is based on SOC and internal temperatures and it shows a limit line where it is sure there is a limit. When flooring the accelerator and the temperature is low enough that at full power draw the extra resistance is seen by the car then the limit line shows up. Regen is similar but when the limit doesn't show up it is not exactly known where it should be do to energy being added to the battery which is increasing the temperature and charge acceptance of the battery. and it is harder to charge a cold battery than it is to take power out of it so more finicky regen limit and it always shows before output limit (at mid-high SOC)

 

[Duckjybe]

Regen is similar but when the limit doesn't show up it is not exactly known where it should be do to energy being added to the battery which is increasing the temperature and charge acceptance of the battery. and it is harder to charge a cold battery than it is to take power out of it so more finicky regen limit and it always shows before output limit (at mid-high SOC)

I can see power output being hard to predict, however not sure about regen. Especially given the consistent way the line never seems to display from 40-60kW. The regen line drops slowly as the battery warms up to about 35-40kW if I can remember correctly. Then the line disappears but I still exhibit limiting around 40-50kW for quite a while. So this suggests that the limit is still known but they have chosen not to display it because it is close to being gone. I can guess that they felt it was an unnecessary distraction given the regen limiting was small and therefore not a safety concern. I would still prefer to see it. I most certainly do notice the regen limited to 50kW when coming off the highway.

 

[Andyw2100]

People interested in this thread about the regen limit might be interested in the following thread about trying to get Tesla to offer a battery pre-heating option:

Suggestion for battery pre-heating and charge-end scheduling sent to Tesla



There's also a poll on the pre-heating option you may want to answer here:

Would you use battery heating if it were available?

 

[David29]

As a new owner (car delivered in late September), I am still getting used to the car's behavior. I was not surprised that I saw the regent limit yesterday morning when it was fairly cool out, but I was surprised when it was still there when the air temperature rose to a fairly balmy 61F by late morning. It did eventually disappear but I did not note exactly when.