limited regen after car charged/plugged in?

tomp · Feb 5, 2015

The other day I charged at work (J1772). My car finished charging a few hours before I left to go home. When I unplugged and started driving, I was surprised that I still got the dashed yellow 'limited regen' indicators. Shouldn't the car 'keep the battery warm' when it is plugged in? Or am I confused about something?

Thanks!

deonb · Feb 5, 2015

Did you charge to 100%?

If so, you're regen limited due to the high charge, not the low temperature.

Vger · Feb 5, 2015

You have to pre-condition the car (from the app), and make sure you are NOT in Range Mode to get pack heating before departure. Just being plugged in does not do it. Charging will generate some heat, but if charging ends (as you say) a few hours before departure, that residual heat will dissipate.

tomp · Feb 5, 2015

Thanks - I was not charged to 100%.

deonb said:
Did you charge to 100%?

If so, you're regen limited due to the high charge, not the low temperature.

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I might have been in range mode, I'll need to check that - thanks.

However, I'm surprised that the car/battery doesn't 'maintain pack warmth' when plugged in. Wouldn't this seem like preferred behavior?

Vger said:
You have to pre-condition the car (from the app), and make sure you are NOT in Range Mode to get pack heating before departure. Just being plugged in does not do it. Charging will generate some heat, but if charging ends (as you say) a few hours before departure, that residual heat will dissipate.

jerry33 · Feb 5, 2015

tomp said:
However, I'm surprised that the car/battery doesn't 'maintain pack warmth' when plugged in. Wouldn't this seem like preferred behavior?

No. That would vastly increase vampire energy use. The best way is to use the timer to allow the charging to complete shortly before driving and then preheat the car. Range mode should be off while charging.

arijaycomet · Feb 5, 2015

jerry33 said:
No. That would vastly increase vampire energy use. The best way is to use the timer to allow the charging to complete shortly before driving and then preheat the car. Range mode should be off while charging.

And this is precisely why Tesla needs to add "end time" charging, the same way Nissan does. We would always end charge our Nissan Leaf so as to sit at high SOC for low periods of time, and also make sure the pack was warm when we left the house for work etc. I'm surprised Tesla hasn't added this capability.

Also, another point to mention is that drawing power from the wall just to keep the batteries warm would also cost money that many users might not want. Still I just precondition the car to handle this, and love the new auto smart preconditioning feature for this matter.

jerry33 · Feb 5, 2015

arijaycomet said:
Also, another point to mention is that drawing power from the wall just to keep the batteries warm would also cost money that many users might not want.

Right. Using the App to preheat the car doesn't seem to cost much, as my total electric bill was $113 last month. I pre-warmed every day, usually for two cycles, and drove ~1500 miles (two Supercharges). However, to keep the preheating on all the time it was plugged in would have used a lot more energy.

skilly · Feb 5, 2015

when you drive on a charge that is full enough, regen becomes limited in its ability to give back life to the battery. This will be depicted on the speedo with a dotted yellow line across the maximum range of regen allowed. As you drive father this will scale down the regen power indicator and finally disappear and max regen will commence again. Its most apparent of course when you charge to 100% - it almost completely eliminates regen...driving for a few miles and you will see it return to normal.

tomp · Feb 5, 2015

skilly said:
when you drive on a charge that is full enough, regen becomes limited in its ability to give back life to the battery. This will be depicted on the speedo with a dotted yellow line across the maximum range of regen allowed. As you drive father this will scale down the regen power indicator and finally disappear and max regen will commence again. Its most apparent of course when you charge to 100% - it almost completely eliminates regen...driving for a few miles and you will see it return to normal.

Agreed - in this case, however, the limited regen is due to cold, not a high SOC.

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jerry33 said:
No. That would vastly increase vampire energy use. The best way is to use the timer to allow the charging to complete shortly before driving and then preheat the car. Range mode should be off while charging.

I'm confused on two points:

1) Vampire energy use when the car is plugged in?? I don't see why vampire energy use is a concern if the car is plugged in; even if the SOC should drop a bit below the target (e.g. 88-89% when set to charge to 90%), doesn't the car re-initiate charging to get back to target?

2) "use the timer"... what timer?
Thanks!

jerry33 · Feb 5, 2015

tomp said:
Vampire energy use when the car is plugged in?? I don't see why vampire energy use is a concern if the car is plugged in; even if the SOC should drop a bit below the target (e.g. 88-89% when set to charge to 90%), doesn't the car re-initiate charging to get back to target?

2) "use the timer"... what timer?

1. Vampire energy is the energy the car uses when not driving.

2. You can set the charge to start at a specific time. Unless you have a very erratic schedule, it's easy to figure out how much actual charging time is needed and set the charging start time accordingly. On those days where you need additional charging (e.g. just before or after a trip) just use the App to start charging for until you reach the normal low point of the day.

wycolo · Feb 6, 2015

TM makes every effort, or so it seems, to conserve kwh at every opportunity. So will always interpret your requests in this light as it tries to reach the chosen charge limit as quickly as possible.
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limited regen after car charged/plugged in?

tomp

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deonb

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Vger

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tomp

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jerry33

(S85-3/2/13 traded in) X LR: F2611##-3/27/20

arijaycomet

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jerry33

(S85-3/2/13 traded in) X LR: F2611##-3/27/20

skilly

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tomp

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(S85-3/2/13 traded in) X LR: F2611##-3/27/20

wycolo

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