will PiP stop drawing power when full charge?

The timer works only when you press the button on the dash to engage it, for either "start" or "finish" time. If you don't press it, and plug in the EVSE, it will start charging within a few seconds and shut off when it has finished. For example, I usually charge in the early morning with the timer set to finish charging by 6:00 am. At the end of the day, I simply press the switch (a green light flashes to the right, near the security light) and plug in the EVSE. Occasionally I will also charge during the day, and for that I don't press anything, just plug in and let it charge. I don't believe it has any bearing on whether there is a "vampire draw" as you describe. AFAIK, once it has charged it is off, period. Hope this helps.

 

There is communications between the car and the controller box in the cord. You will notice a click from the controller box shortly after plugging in when it turns on power to the car. This controller is told when the car is finished charging and it will turn off power to the car. There is a vampire draw for the controller but not for the car.

 

I'm pretty sure the last part isn't true. Once the EVSE ("controller box") enables power to flow to the car it stays that way until you physically unplug the car. It is the battery charger built into the car itself that stops drawing power.

As far as I know, the Prius draws essentially no power once the battery is full and the car's charging indicator light next to the plug & socket turns off.

 

The EVSE has controller wires and the "mains" which feed power into the charger. There is a simple relay in the EVSE which turns the "mains" on or off. Nothing in between. The controller in the EVSE consumes a few watts as long as it is plugged in to the utility, regardless of whether the EVSE is plugged into the car.

 

There is a ~1.4 watt for the EVSE when it is plugged it. It draws this much if the car is not plugged in, it draws this much if the car has finished charging and is still plugged in, etc.

Mike

 

I think jfscultz is correct here, at least with my system.
I use a 2013 Leaf portable EVSE. When charging, the orange 'charge' indicator blinks, however, when charge finishes (and still plugged) this indicator is off and the green 'ready' indicator blinks to indicate that the EVSE is ready to use (no live contact in the plug). Same thing happens when I interrupt charging.

This way or another, the most important thing is that when the plug is removed both sides of the j1772 connector have no live contact.

EDIT: My EVSE is an American one for 120V upgraded by EVSE Upgrade to use with 208-240V as well (auto detecting voltage) it could be that the feature I am describing here is one of their (good) upgrades added to the system.

 

I'm not an expert on the specification or the actual implementation of it on various cars. I'm just speaking from practical experience as a user. The standard appears to allow for a car to signal the EVSE that it no longer needs power so the contactors (relays) on the EVSE will "open" and de-energize the power pins going into the car. Maybe the Prius Plugin actually does this. Or, maybe the EVSE indicates charge completed (ready light) when power flow drops below some fixed level even if the car has not requested the power pins to be completely de-energized.

On the Volt, I don't hear the contactors open until I squeeze the J1772 handle to unplug it from the car or until I end the charging session by placing my ChargePoint RFID card on the charging station. Perhaps the car does this so it can draw power in the future for the battery temperature management system if the car is parked in a hot climate. I know some cars will also continue drawing power at a lower level after the main charging event is over in order to continue circulating coolant through the battery and radiator or blowing a cooling air fan for a short time in order to equalize the cell temperatures.

Because some cars do this, I believe EVSE's like ChargePoint cannot always instantly determine when the charging is complete simply based on noticing the open contactor transition (EV charging state to EV ready state transition signalled optionally by the car). For example, ChargePoint delays SMS notification to the user that charging is complete for 15 minutes after the power flow is reduced.

 

When the charge-level reaches 85% (full), the draw from the charger will stop and the timer will be cancelled (no longer set).

It's still connected to the system though. So, if you turn on the A/C remotely, that electricity will automatically be replaced.

 

There is also a trickle charge going to the 12v battery anytime the PiP is plugged in.

 

It appears that whether the EVSE will "open" and de-energize the power pins going into the car is a design issue. There is probably a requirement that the connector is de-energized when unplugged.

I ran a quick check with the EVSE that came with the Plug-in Prius. After charging for a while, I heard the relay click when I held the trigger to disconnect. Later after a full charge there was no relay click. So that would indicate that the included EVSE de-engergizes on a full charge.

So the answer to the original question is that it depends on the EVSE being used. If the EVSE de-energizes when the charge is complete there is a vampire draw only in the EVSE and not the car. If the EVSE only de-energizes on disconnect then there is a vampire draw in both the EVSE and the car.

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This is not true. I have tested it with a volt meter. The 12V battery is only charging when the main battery is charging. Once the charge cycle stops (and the charge light turns off), the 12V battery also stops charging.

 

If I plug in just the EVSE and measure the power consumption I see 1.4 watts. If I plug in and charge, wait til the charge is complete and note the power consumption it is 1.4 watts. Sometimes the last digit goes to a 3, then back to a 4...so within the accuracy of the Watts Up Pro (a bit more accurate than the Kill-a-watt meter) there seems to be no vampire load due to the car once the charge is complete. Might be different from a commercial ChargePoint station, maybe.

Mike