Can't preheat without depleting battery.

[TickTock]

I am charging to 100% (using END timer) these days and recently have started pre-heating as well. I noticed that my SOC is lower when I do this. Usually around 94, but once was as low as 92.5. Today I did a little more controlled experiment. I logged the data before and after pre-heating as well as attempted to top-off after turning the pre-heat off. The observation is, even after turning off the pre-heat and "topping off", my stored capacity as indicated by gids and SOC is lower. Curiously, it read even lower after topping off. I know energy went in so I assume instrumentation error is involved.

Below are the results:

End of day prior:
gids=19
SOC=11.1%
pack volts=340.5

100% charge complete:
gids=219
SOC=95.6%
pack volts=394.5
Wall power=+18.5kWh

After 33 minute pre-heat (while plugged in):
gids=217
SOC=94.7%
pack volts=394.5
Wall power=+0.9kWh

After "top-off" (turned off pre-heat, pressed the charge timer override):
gids=216
SOC=94.1%
pack volts=394.5
Wall power=+0.1kWh

 

[edatoakrun]

I am charging to 100% (using END timer) these days and recently have started pre-heating as well. I noticed that my SOC is lower when I do this. Usually around 94, but once was as low as 92.5. Today I did a little more controlled experiment. I logged the data before and after pre-heating as well as attempted to top-off after turning the pre-heat off. The observation is, even after turning off the pre-heat and "topping off", my stored capacity as indicated by gids and SOC is lower. Curiously, it read even lower after topping off. I know energy went in so I assume instrumentation error is involved.

Below are the results:

End of day prior:
gids=19
SOC=11.1%
pack volts=340.5

100% charge complete:
gids=219
SOC=95.6%
pack volts=394.5
Wall power=+18.5kWh

After 33 minute pre-heat (while plugged in):
gids=217
SOC=94.7%
pack volts=394.5
Wall power=+0.9kWh

After "top-off" (turned off pre-heat, pressed the charge timer override):
gids=216
SOC=94.1%
pack volts=394.5
Wall power=+0.1kWh

Wouldn't you expect the gid count to be lower, and the corresponding Wh content of each gid to be higher, due to battery warming during the pre-heat and top-off operations?

 

[TickTock]

I am charging to 100% (using END timer) these days and recently have started pre-heating as well. I noticed that my SOC is lower when I do this. Usually around 94, but once was as low as 92.5. Today I did a little more controlled experiment. I logged the data before and after pre-heating as well as attempted to top-off after turning the pre-heat off. The observation is, even after turning off the pre-heat and "topping off", my stored capacity as indicated by gids and SOC is lower. Curiously, it read even lower after topping off. I know energy went in so I assume instrumentation error is involved.

Below are the results:

End of day prior:
gids=19
SOC=11.1%
pack volts=340.5

100% charge complete:
gids=219
SOC=95.6%
pack volts=394.5
Wall power=+18.5kWh

After 33 minute pre-heat (while plugged in):
gids=217
SOC=94.7%
pack volts=394.5
Wall power=+0.9kWh

After "top-off" (turned off pre-heat, pressed the charge timer override):
gids=216
SOC=94.1%
pack volts=394.5
Wall power=+0.1kWh

Wouldn't you expect the gid count to be lower, and the corresponding Wh content of each gid to be higher, due to battery warming during the pre-heat and top-off operations?

Yes, in theory. However, I wouldn't expect heating the cabin for 30 minutes to have a noticeable impact on the battery temp - especially coming right after a charge when the battery is already warm (I saw a rise in the battery compartment temperature during charging). I suppose I could take a look a the temperature during this experiment (my temperature datalogger is still be installed) when I get home.

 

[gschettl]

Hmmm, what are "gids" and how do you get a battery pack voltage reading? Thanks, Gary

 

[TonyWilliams]

15 minutes of preheat inside a 20 degree garage has my Leaf toasty warm. The warmth lasts about 10 miles before my feet get cold. I do not see a need to preheat any longer than that. Also, I, too notice that a 80% charge with preheated Leaf does indicate 9 bars when I depart each morning.

As pointed out above, you might depart with 10 or even 11 bars with a longer preheat. Plus, with a "heat soaked" car, your feet might not get cold in 10 minutes.

Anything you can do to warm up the battery helps.

 

[planet4ever]

Hmmm, what are "gids" and how do you get a battery pack voltage reading? Thanks, Gary

Follow the link in the signature on Gary's post: See SOC/GID-Meter Info

Also, check out the wiki glossary, or the wiki in general, for questions like this.

Ray

 

[mazdaboi]

No issues here using the CARBUDDY on WP7 or LEAF_LINK on iOS. We preheat our leaf every morning, (car stays at 80%). I do notice If the car is still charging and you turn on CC, it takes 2x as long to charge, but we rarely do this.

If you feel like your loosing battery while plugged in and using CC, override the EVSE/Car and start charging then turn on CC. So atleast you will gain a little bit before you start to venture out. Extra battery is always a plus when the inefficient heater is being used.