RAV4 PHEV Charging restarts even when 100%.....

[TonyFR]

I have noticed that even when the car is 100% charged (according to MyT) - and the charging cable is still connected , of course - that the charging process appears to start up for a while, then stop again. We now have quite cold temperatures where I live (often sub-zero). Would the process I am seeing be that the Battery is being kept warm (as opposed to actual charging)?

[nlee]

Is it on a schedule? Mine does that if I do a full charge then leave it plugged in and the next schedule starts. I presume it tops up the drain or background use. Similar to if you had rechargeable batteries on a charger, unplugged it for a period then plugged it back in, it would charge for a short period. I normally unplug now if I'm not going to be driving anywhere that day and it doesn't seem to affect the range. Even if you're not on a schedule, I guess it's doing the same thing really.

[ernieb]

Nigel, I think what’s happening, as you say put a fully charged Battery into a charger and it starts the charge cycle until it measures the Battery charge rate and then stops.

[TonyFR]

Yes it's on a schedule, and finishes typically around 7am. When I Ieave it plugged in, it does this occasional "charge" (i.e. the green light comes on on the granny cable connector box (whatever that's supposed to be called)) within even 3 or 4 hours of finishing the 100% but, as I mentioned,  it is very cold right now. I am trying to find out if the Battery management system is doing something smart other than re-charging (which seems a bit unlikely). Or maybe there is a fault?!

[Nick72]

Mine does the same. Reaches full charge from the wall box but if left plugged in it starts the charge cycle again for a short period of time. Suspect the charge is falling off with time and temperature below the threshold at which a charge cycle is started? In other words, more hysterisis may have been necessary in the design?

[Nick72]

Just checked my wall box app but unfortunately it is only listing the time connected and total input energy (kWh). So, it has been left plugged in the last couple of days (not had a need to drive anywhere) and it says 15.X kWh over 38 hours. It was empty when plugged in so 15kWh is about right, considering the reserve. The 38 hours is the total time connected but during this time it will have charged to full in under 3 hours. Big Green logo illuminated on the wall box. Think something has changed in the wall box app because previously it would record only the length of time spent charging in the history page. Connection time unhelpful. Charging times are helpful. 

But I see the wall box come on now and again indicating it is charging.

 

I've not been that bothered about getting to the bottom of it because the right amount of energy is going in. No more, no less.

[nlee]

38 minutes ago, TonyFR said:

Yes it's on a schedule, and finishes typically around 7am. When I Ieave it plugged in, it does this occasional "charge" (i.e. the green light comes on on the granny cable connector box (whatever that's supposed to be called)) within even 3 or 4 hours of finishing the 100% but, as I mentioned,  it is very cold right now. I am trying to find out if the battery management system is doing something smart other than re-charging (which seems a bit unlikely). Or maybe there is a fault?!

When I was using the granny cable the green light would come on briefly when first attached even though the schedule wasn't ready for it. This caused the plug to lock in the socket. Now I use a wall charger with the schedule set on that, the plug doesn't lock until the scheduled charge starts. I suspect this is by design and I think Ernie's comment is probably closest to the reason. Probably nothing too smart on the Battery but the charger "checking" the Battery state and topping up as required.