Yan
Posts: 4
Joined: Tue Nov 12, 2019 10:33 am
Delivery Date: 12 Nov 2019

Preheating cabin use battery

Tue Nov 12, 2019 10:50 am

Hello everyone. I’m the owner of an 2014 Leaf SV. I have a 240v 30 amps capacity charging station at home.

The question is: why do the cabin preheating is reducing the % of charge of the battery pack when the car is full and still pluged in?

It is not supposed to draw the electricity from the charger/charging station?

It is because the heating system use primarly the energy in the pack and the charger kick in when the battery pack pass a % threshold?

This morning the car was plugged in and already full way before the cabin heating program kick in. When I came to drive the car, the % had dropped to 97%. Since my charger capacity into the car is 6.6kW the charging station up to 7.2 kW and energy consumption from the heater never goes over 5 kW.... I dont understand the drain.

Thanks for the explanation.

goldbrick
Posts: 918
Joined: Tue Aug 01, 2017 3:33 pm
Delivery Date: 01 Aug 2017
Leaf Number: 311806
Location: Boulder, CO

Re: Preheating cabin use battery

Tue Nov 12, 2019 12:51 pm

When the battery SOC gets higher and close to 100% the charge rate tapers off. It doesn't run at 6.6kW until 100% but starts to taper down around 90% SOC I think. Eventually, when you charge to 100% it tapers to 0kW then there are 3 small charge bumps while the charger 'tops off' the battery.

If you try the same experiment at 50% SOC I would be surprised if the SOC goes down while the car is plugged in.

LeftieBiker
Moderator
Posts: 15334
Joined: Wed May 22, 2013 3:17 am
Delivery Date: 30 Apr 2018
Location: Upstate New York, US

Re: Preheating cabin use battery

Tue Nov 12, 2019 2:09 pm

There is already at least one topic on this, but here is the short answer: the climate control draws power from the battery pack only. The EVSE (via the onboard charger) charges the battery pack only - it doesn't power anything else. So if the EVSE provides charge at a slower rate than the climate control uses it, the charge level drops accordingly. You need at least a 16 amp, 240 volt EVSE to prevent this. If you want to charge at the same time, then at least a 20 amp 240 volt EVSE.
Scarlet Ember 2018 Leaf SL W/ Pro Pilot
2009 Vectrix VX-1 W/18 Leaf modules, & 3 EZIP E-bicycles.
BAFX OBDII Dongle
PLEASE don't PM me with Leaf questions. Just post in the topic that seems most appropriate.

User avatar
Nubo
Posts: 5735
Joined: Fri May 28, 2010 11:01 am
Delivery Date: 31 Oct 2014
Location: Vallejo, CA

Re: Preheating cabin use battery

Tue Nov 12, 2019 2:27 pm

^^ I think if you combine the previous 2 replies you have the full answer. Heater draws from the battery, EVSE tries to keep the battery charged, but charge rate is reduced when near 100%. As state of charge drops you will reach an equilibrium point where the charge rate allows the EVSE to keep up. Once the cold-soak of the cabin is eliminated that equilibrium point may shift upwards a bit.

How many percent are you losing?
I noticed you're still working with polymers.

Yan
Posts: 4
Joined: Tue Nov 12, 2019 10:33 am
Delivery Date: 12 Nov 2019

Re: Preheating cabin use battery

Tue Nov 12, 2019 7:37 pm

Like I wrote in my first message:

- Car was plugged but the SOC was at 100% several hours before the preheating program start.
-My home charging station a level 2 unit ( not a EVSE) is a 240v 30 amp (7.2 kW) model and capable to do so.
- The cabin preheating started way after the full charge was attained but I loose 3% (SOC dropped from 100% to 97%)

So from here, I dont understand why the car is not asking for charging power from the charging station since the heater was consuming electricity from the battery and depleting it.

When I read user manual, it was supposed to.

3% is about 800-1000 Wh . it’s not a big deal. But in winter time, when it’s minus 15c , every kW count. And using preheating when the car is plugged in, its supposed to avoid this.

Yan
Posts: 4
Joined: Tue Nov 12, 2019 10:33 am
Delivery Date: 12 Nov 2019

Re: Preheating cabin use battery

Wed Nov 13, 2019 8:22 am

Is it possible that the car system only ask for charging , in preheating condition, only when battery SOC status is on a particuliar level or threshold?

User avatar
Nubo
Posts: 5735
Joined: Fri May 28, 2010 11:01 am
Delivery Date: 31 Oct 2014
Location: Vallejo, CA

Re: Preheating cabin use battery

Wed Nov 13, 2019 12:58 pm

Yan wrote:
Tue Nov 12, 2019 7:37 pm
... I dont understand why the car is not asking for charging power from the charging station since the heater was consuming electricity from the battery and depleting it. ...
Almost certainly it IS asking for charging power, and the EVSE is supplying it. But the vehicle won't charge the battery at the full rate when it is near 100%. The following image shows how the charge rate tapers when the battery is nearly full.
Image
I noticed you're still working with polymers.

LeftieBiker
Moderator
Posts: 15334
Joined: Wed May 22, 2013 3:17 am
Delivery Date: 30 Apr 2018
Location: Upstate New York, US

Re: Preheating cabin use battery

Wed Nov 13, 2019 1:24 pm

Almost certainly it IS asking for charging power, and the EVSE is supplying it. But the vehicle won't charge the battery at the full rate when it is near 100%.

This is it. I didn't notice that the OP was using a 30A EVSE. My bad for misreading.
Scarlet Ember 2018 Leaf SL W/ Pro Pilot
2009 Vectrix VX-1 W/18 Leaf modules, & 3 EZIP E-bicycles.
BAFX OBDII Dongle
PLEASE don't PM me with Leaf questions. Just post in the topic that seems most appropriate.

jjeff
Posts: 2139
Joined: Wed Jan 13, 2016 9:10 am
Delivery Date: 13 Jul 2014
Leaf Number: 422121
Location: MSP MN

Re: Preheating cabin use battery

Wed Nov 13, 2019 3:21 pm

I believe what's happening(and I've noticed it too with my 30a EVSE and my 6.6kWh Leaf charger) is the battery is near(or at 100%) so it doesn't call for a full 27.5a that the car can draw, it just takes a top off amount which unfortunately isn't enough to keep up with the preheat draw. The only way I've found to avoid this is to set my '13 to 80%(you won't have this option on your '14 :( ) and set to 80% when the preheating starts the battery is low enough to basically draw the full amount the preheat is using from your EVSE. I know this won't do you any good if you want a 100% charge but it's just the way it is. Note you won't really lose more than a max of 3% off 100% from what I've observed but I understand when you want a full 100% you might feel cheated only getting 97%.
2012 SL purchased used 2/'16
2013 S w/QC purchased new
Juicebox Premium 60a L1/L2 EVSE, Ebusbar 16a L1/L2 EVSE
'12 EVSEupgrade'd 20a L1/L2 EVSE, '13 EVSEupgrade'd adjustable 6-20a L2, 6-13a L1 EVSE
Zencar 13, 20, 30a L1/L2 portable EVSE
GE Durastation 30a

Yan
Posts: 4
Joined: Tue Nov 12, 2019 10:33 am
Delivery Date: 12 Nov 2019

Re: Preheating cabin use battery

Wed Nov 13, 2019 5:30 pm

Sorry for not calling my charging station a EVSE. I always belived that only portable charger was named EVSE.

Thanks for your reply guys. :D

Return to “Range / Efficiency / Carwings”