FFE Charger Current after Fully Charged?

I plugged the 120v charging cable that comes with my new 2014 FFE into a garage 120V outlet thru a "Kill-A-Watt" device so I could check voltage and current draw.

When the car was charging at maximum the voltage dropped to 110V (due to the high current over the power cabling to that far side of the garage I assume) and the current draw was about 11.5Amps, so about 1270Watts giving 1.27KW/hour during active charging. The Ford charger cable unit green light was blinking during the charging process.

When the car reached full 100% battery charged, the green light went steady for a while.
But later it started blinking again even though the battery was fully charged and seems to draw about 0.5Amps in this state. This is with the car "off" not in auxilary mode so no climate control, no lights no, no accessories on.
What is the car using that 0.5Amps at 120V (about 60W) for when the battery is fully charged?
The temp in the car this afternoon is in the mid 80s probably for reference, so it might partly be the car keeping the battery cooled?
How about the 12V lead-acid accessory battery? Does the car have it trickled charged in the state when the charge plug is in?

I've ordered a 240V 30A charger unit thru Home Depot yesterday with their special $100 off discount that expires today.
So I'm curious what is the current draw with the 240V unit in that same state after the battery is fully charged?
I don't know of anyway to measure the current on a 240V line easily (after ask an electrician about that when I get quotes for a 240V installation) like I can do with the Kill-A-Watt device on the 120V line.

Some EVSE's report the current draw, and some people have a separate meter for the FFE.

In my case I have both: My Juicebox will report out the power consumption when its providing power to the car and I have a TOD rate for the car which means it has its own meter.

Frankly I haven't really paid that much attention to the current draw while the car wasn't charging.

It is also possible that the 1/2 Amp draw was the EVSE circuitry itself (although that does seem a bit high for what the EVSE provides). The TMS in the car is going to consume a lot more power than that!

You can check if its keeping a trickle charge on the 12V battery: measure its voltage when its in that state--if its higher than the 12V nominal its charging the battery.

I'd guess that it was charging the 12V battery. Our EVSE has a light to show when it's charging. Usually when we come down to the car it shows that it is not charging (when there's no Go Time causing pre-conditioning). However, as soon as we unlock the car or open a door the EVSE relay clicks and the charging light comes on. Based on my observations with the Fusion Energi and Torque Pro it appears that when that happens the car enables the DCDC converter and draws power from the wall to power the lights, etc instead of draining the 12V battery.

The provided 120v charger only appears to use 2-3W (0.02A) when not plugged into the car.
Thats the same I measure when the car is not charging and not in the in-between mode sometimes where it takes about 0.5A (60W) which is probably powering some accessories perhaps charging the 12v battery and/or cooling system for the battery. Seems to cycle on and off that way after the HV battery is fully charged.

I checked this more closely yesterday and when in that mode where its drawing about 0.45A at 120V, my Kill-A-Watt meter reads a much lower power factor about 0.25, so the actual power used displays as only about 14Watts.
It doesn't appear to be charging the 12v battery since it measures about 12.5V at that time.
This is all with the car in "OFF" mode and no lights or accessories on or plugged in.
It seems to cycle after the HV battery is fully charged between truly off (charger unit green indicator light off) and low power non-charging (charger unit green indicator flashing like it does when its full charging, but only drawing ~14watts).
I'm just curious what the car is doing with that ~14watts at times, perhaps keeping the HV battery temp cool on a warm day or perhaps an ultra-low trickle charge cycled for maintenance?

14 watts is nothing. I highly doubt that the TMS is doing anything at that low power draw. I would suspect 14 watts is just the losses of keeping the relays energized inside the EVSE and other circuitry inside the car simply being powered up and not doing anything. Or it could be the current the car uses to keep the HVB relays engaged.

The battery system has a cell rebalancing mode where it supplies 100mA (@ 350Vdc [possibly with a modulating waveform?]) to the battery packs. I believe that it enters this mode when it detects cell variation > 20 mV once it reaches full charge. Generally it should not stay in that mode for long although a service tech I spoke to said that his manual states: "up to 24 hours to rebalance".

During cold weather (< 40 deg) I believe that you will see a larger draw as the TMS cycles to keep the HV battery warm.

GladeStorm said:

The battery system has a cell rebalancing mode where it supplies 100mA (@ 350Vdc [possibly with a modulating waveform?]) to the battery packs. I believe that it enters this mode when it detects cell variation > 20 mV once it reaches full charge. Generally it should not stay in that mode for long although a service tech I spoke to said that his manual states: "up to 24 hours to rebalance".

Click to expand...

That might be what its doing when its in the ~14watts mode, it seems to cycle between that and charging off after the HV battery is fully charged. I hear no sounds in this mode either.