Vampire power use from the charger.

I do my main charging at work, and use the occasional use charger at home... occasionally. But the other day I took it off the wall to take on a trip, and it was warm. Not hot, but fairly warm when it had not been plugged into the car in weeks. It was plugged into the wall. So here it is using power 24/7 not charging my car.

Obviously I can just unplug it, but what about permanently wired in charger with much higher capacity? How much power does that use?

An EVSE is still an electronic device...it has a power supply and a logic board in addition to a power contactor. The power supply lights the status lamps and powers the logic board which has interlock signals and the power to energize the contactor. The vast majority of power it uses is when supplying line voltage to the car. I have a power meter on mine, and it seems to draw only about 2-3W when not charging the car. Depending on the construction, and some may also have a WiFi connection, you'll have a bit more power needed. SLoppy design could have the power supply drawing more power in standby, but it shouldn't exceed say about 10W. At 2W/hr, mine uses less than a Kwhr in a month...not a whole bunch. Sure, you could unplug it or turn the CB off if you wanted. In the big scheme of things, your TV and most other things that work via a remote in the home probably use a lot more power.

Tacfoto said:

Obviously I can just unplug it, but what about permanently wired in charger with much higher capacity? How much power does that use?

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I suppose you could flip the breaker if you were concerned about it

We are urged to save electricity in our homes by eliminating vampire loads. Here in Honolulu, most electricity is generated by petroleum-powered generators which add significantly to the atmospheric CO2 levels adding to noticeable sea level rise that is already damaging shoreline infrastructure here. Even though vampire loads are a small percentage of total electricity consumption, we're past the point where we can ignore even small CO2 emissions.

I have connected all of our household appliances that are always on (e.g., TV, Apple TV, TV sound bar, etc.) to switchable power strips which I turn off when the appliances won't be used for a while. I treat our EVSE the same way. Why should it sit unused for a huge percentage of the time in our case consuming standby power which includes driving its LCD?

A circuit breaker isn't designed to be turned on and off repeatedly. We installed a high-power circuit shut-off switch next to our EVSE which I turn on when I charge and turn off at all other times. Sure, the short-term cost of this switch would exceed the cost of electricity savings for a long time, but we now must also consider the external costs of the CO2 that this needlessly consumed electricity would produce.

alohart said:

A circuit breaker isn't designed to be turned on and off repeatedly. We installed a high-power circuit shut-off switch next to our EVSE which I turn on when I charge and turn off at all other times.

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Good point. Thanks for the follow up