Charging to 80% problem...

[UkrainianKozak]

On couple occasions I noticed that my Leaf charged itself to 100% when timer was set to 80%...
I suspect is it is because of the preheat or something... haven't noticed this before... Anyone knows if Leaf actually charges when preheat is on?
My pattern of usage on this 2 occasions was similar:
I haven't touched my timers in a while, and I have one timer on for all days, with no start and end time at 4AM.

The day before: charged to 80% (using timer), drive turn on timer override, charge for about an hour, drive to almost empty.
Morning, charging timer supposedly cutoff at 80% at 4AM. I had a preheat timer set for departure at 6AM, but I was leaving at 8AM those days, so when I come to the car at 8AM everything is off, but battery is charged to 100%...

The only thing that comes to my mind is that because of mild temperatures heater is not drawing a lot of power, but it actually maxes charger capacity, directing the leftover to charge battery. I know that if you do preheat leaf can draw additional power from battery if needed, even when connected to EVSE, does it work in reverse as well (if heater do not need power charger charges battery instead of discharging it)?? I wasn't expecting that...

I'm pretty sure I didn't hit override timer button as I heard EVSE relays clicking twice, to connect and disconnect... And it happend twice both times when I was departing late...

Any ideas?

 

[ebill3]

I have never used a timed pre-heat, but I know that if I am charged at 80% and then use carwings to pre-heat, charging restarts and goes to 100%. Seems likely the same would happen with a timer pre-heat.

 

[Roadburner440]

If you use a timed pre-heat it will charge the car to 100% if left plugged in long enough. This happens all the time. I figure it is probably because the car is drawing more power than the charger can supply initially for the heater, and then in just continues charging. Usually for my car to hit 100% it has to be pre-conditioning for a half hour or so. My best advice is just to try and time it closer to when you are actually leaving. Also the pre-heating time appears to be the time that you want the car fully preheated at, so the preheat is actually coming on approximately 10 minutes before the actual time you set. I will note that I use the Nissan Leaf App to program the time for preheat from my phone, and not the in car radio if that affects anything.