Why does Leaf charge when plugged in and pre-conditioning?

[Ingineer]

The power consumed by the heater during pre-heat can be initially high, but then drop down a lot once the cabin has reached the set point and the heater is just working to maintain the differential between 77F and the ambient temperature. If you watch the energy usage screen while driving you've probably seen this. It will be even more pronounced in a garage where there's no wind blast robbing heat from the car. Even less power is needed in an attached garage where the temp is a bit warmer. And the garage itself is getting a bit warmer from the car's heat loss... Once you get to where the heater is only drawing maybe 0.5 to 1 kW, the leftover power is giving you a pretty hefty battery charge.

This is a correct assessment, Thanks Nubo. So if you reduce your pre-conditioning time to the minimum need, you'll have less excess charging.

-Phil

 

[GaslessInSeattle]

it is pretty rare that I do an extended prewarm, but when it gets cold here, a prolonged prewarming is necessary to stay warm for any length of time and still get good range without being forced to use the energy black hole that is the resistive heater. sadly, the foot defog sends cold outside air to your feet, not just the windshield, quickly negating anything but a prewarming session long enough to warm the core of the car. In any cse, up north here, it's pretty evident that a substantial amount of energy goes to charging the battery during pre-warming once the car gets warmed up initially. curious to see if the 2013 does this, of course the heat pump will probably reduce the need to do prolonged pre-warming since range will be effected less by keeping the heater on while driving.

this is confusing to me, if it were just a little electricity than how come if prewarm starting with an 80% charge it will charge up to a SOC of 100% in an hour or so? when it gets cold up here and I have a long way to drive, extended prewarms are necessary. in the process of experimenting with extended prewarming, I've found that the amount of "bypass" to the battery is quite high. this has been true for both the MY 2011 and 2012.

You are obviously Pre-conditioning way too long. Precondition for the minimum time needed to get the car comfortable and the extra charge will not have time to happen.

FYI, the Leaf pack never makes it to 100% SoC. It tops out around 95%, so from 80% to 95% is only 15% more.

-Phil

 

[Ogi]

Thanks - was informative from the answers - if still a bit vague. Much like visiting a consultant!

 

[GaslessInSeattle]

the car is garaged, the door however is a POS and does little to keep the garage warm. we get cold snaps here on occasion, nothing brutal but it gets into the 20's and sometimes teens, cold enough that one begins pondering the wonders of all that waste heat from an ICE that was taken for granted all those years. From what I can tell, prewarming seems to set to charge at nearly the normal rate minus the energy draw of climate control as it throttles up and down. if done from 100% SOC the time allowed is limited apparently by the BMS and shut off automatically, but considering how much juice goes to the battery, it would make sense that the pre-conditioning allows for overcharging to some extent. given all that has come up about the battery premature degradation, it would seem worthwhile to avoid frequent prolonged pre-conditioning from 100% SOC, as it is essentially "topping off" which is not recommended in the manual. I have wondered if those in hot climates using pre-conditioning frequently aren't essentially topping off, compounding the effects of high heat with extra high SOC, I can't imagine it's good for the battery.

this is confusing to me, if it were just a little electricity than how come if prewarm starting with an 80% charge it will charge up to a SOC of 100% in an hour or so?

The power consumed by the heater during pre-heat can be initially high, but then drop down a lot once the cabin has reached the set point and the heater is just working to maintain the differential between 77F and the ambient temperature. If you watch the energy usage screen while driving you've probably seen this. It will be even more pronounced in a garage where there's no wind blast robbing heat from the car. Even less power is needed in an attached garage where the temp is a bit warmer. And the garage itself is getting a bit warmer from the car's heat loss... Once you get to where the heater is only drawing maybe 0.5 to 1 kW, the leftover power is giving you a pretty hefty battery charge.

What are your temperatures, and is your car garaged?

 

[ebill3]

Thanks - was informative from the answers - if still a bit vague. Much like visiting a consultant!

You want absolutes, and you are not going to get them. BTW, you have visited with a consultant - a few posts back. Not me.

Bill

 

[Ingineer]

considering how much juice goes to the battery, it would make sense that the pre-conditioning allows for overcharging to some extent.

Absolutely not true. No current flows once the battery is full. In fact, I almost always see the SoC drop a little if a pre-condition session is started when the pack is full.

-Phil

 

[Stanton]

I have wondered if those in hot climates using pre-conditioning frequently aren't essentially topping off, compounding the effects of high heat with extra high SOC, I can't imagine it's good for the battery.

Besides the fact that this isn't true (the car doesn't continue to "top off"), I have never pre-cooled; the car just doesn't get hot enough sitting in the garage in the morning. Now pre-heating is a different story, but that seems to help warm the battery as well (which is a good thing in the winter).

 

[thankyouOB]

This is a question about trickle charging.
I understand that if I remote charge while plugged in L2, I will draw enough juice to cover the heating and not draw down the battery.

What happens if i am charged to 100% and start the remote climate control while TRICKLE CHARGING, will it draw down the battery?
I am parked indoors at 55 degrees.

I need the range more than the heat, but heat would be nice.

 

[Ingineer]

This is a question about trickle charging.
I understand that if I remote charge while plugged in L2, I will draw enough juice to cover the heating and not draw down the battery.

What happens if i am charged to 100% and start the remote climate control while TRICKLE CHARGING, will it draw down the battery?
I am parked indoors at 55 degrees.

I need the range more than the heat, but heat would be nice.

If you are plugged into 120v, then the heater may draw a little off the battery, but in general it just heats slower. Just be sure to leave your CC on long enough for the car to get warm then recover any energy lost.

-Phil

 

[thankyouOB]

thanks.
mucho. i am going to give it a try for an hour.
with the new tires, i have lost a bit of range.
i am trying to do a longish roundtrip. gloves on!!!

 

[GlennD]

In Southern California I have the car set to heat up so it is warm when I leave for work. My normal 80% charge is around 82.2%. When I get in the car to go to work the charge is between 83% and 84.8% so the energy not needed for the heater is going into the battery.

 

[Ingineer]

thanks.
mucho. i am going to give it a try for an hour.
with the new tires, i have lost a bit of range.
i am trying to do a longish roundtrip. gloves on!!!

I also recommend getting those tires inflated to the max.

-Phil

 

[kovalb]

There is a setting to set charge priority or climate control priority. I have not tried this myself, but I understand that charge priority is the default, so almost everyone is using it. Setting climate control priority should make it so that the car does not charge while pre-conditioning. This is what I heard, but have not checked it myself.

 

[dgpcolorado]

There is a setting to set charge priority or climate control priority. I have not tried this myself, but I understand that charge priority is the default, so almost everyone is using it. Setting climate control priority should make it so that the car does not charge while pre-conditioning. This is what I heard, but have not checked it myself.

As I understand it, charge priority means that preheating won't happen until the car reaches 80% or more. With CC priority, which I use (at L2), the car will charge while it is preheating, after the initial warm-up of the heater bottle. I've never tried to preheat on L1 so I don't have any experience with that.

 

[thankyouOB]

thanks.
mucho. i am going to give it a try for an hour.
with the new tires, i have lost a bit of range.
i am trying to do a longish roundtrip. gloves on!!!

I also recommend getting those tires inflated to the max.

-Phil

I am going to try the mxv4s at 42, and psi them tomorrow, xmas eve. that other trip was fine. i really need to be able to do a 63-mile rdtrip with heater in a temperature of 50 degrees outside.
i think that is really doable, even with my tires.
we shall see soon.