Electricity Draw of Charger When not Charging

i thought i read .2 watts?

 

si, iirc.

 

Just guessing, but I wouldn’t be surprised if my Christmas lights use more than several years worth of EVSE standby power.

I care about electricity usage, switched to LEDs throughout the house, but I don’t unplug the microwave to save the electricity used by the clock, or unplug my router / modem to save a few pennies.

(Yes, I’m being silly)

 

That would be an infinitesimally small amount of draw, I think. I would bet it as much as 60 watts or more. A standard desktop computer uses about 120 watts in sleep mode.

Convert to amps to equate the "capacity" of a battery to see how much "mileage" you are losing: 1 amp for 1 hour is 1 amp hour.

0.2 watts for one hour would equal 0.001667 amp hours at 120 volts.

60 watts at 120 volts for one hour is .5 amp hours

 

Here's something else you might want to consider... what brand and model of electrical receptacle is installed? Some of the less expensive versions are not designed for repeated plugging and unplugging. If it fails and you need to have it replaced, that's going to cost a LOT more than the value of the electricity you saved by unplugging it repeatedly!

 

Just put a switch on the circuit. Problem solved.

 

Fair enough. Except a DPST switch rated at 50 amps will also cost more than the electricity you save by disconnecting the charger

 

Could leave the bare wires sticking out of the box and "switch on" using vice grips or wire nuts. $$$$$ saved!

 

Or flip the breaker at the main service box?

 

Interestingly, circuit breakers are not to be used for current interruption. They are not switches and not rated as switches.

But the point seems to have been missed. Whether the plug and receptacle are connected and disconnected under load or not, that's not the issue here. There are physical contacts between the connectors. Inside the receptacle are (effectively) springs that grab the male pins and prevent the plug from simply falling out. Springs, regardless of the material from which they are created, have a finite duty cycle.

 

Just to be sure that you aren't misinterpreting that I might flip the circuit breaker while my car is plugged in -- I don't do that. I will flip the breaker to off if I think we're going to have severe thunderstorms, of if I won't be using the L2 EVSE for extended periods like a vacation (the EVSE is located outside and not in a garage).

I do also wonder, however, if the EVSE, when the car is not attached, might be drawing enough of a current that might cost me something. Or, might such a constant low current keep the humidity at moderate levels and help protect it from corrosion?

 

You may. It may reduce the working life of the breaker. Can I guarantee you that? Nope.

 

Well, I had a 200 amp breaker box fire that shut my business down for three full days when a pair of 30A breakers failed while under constant load from one of the central air conditioners when temps were near a hundred degrees for a week. So I do know that failure is always an option.

 

Relevant portions of the National Electrical Code:

NEC 2011
404.11 Circuit Breakers as Switches. A hand-operable circuit breaker equipped with a lever or handle, or a power-operated circuit breaker capable of being opened by hand in the event of a power failure, shall be permitted to serve as a switch if it has the required number of poles.

Informational Note: See the provisions contained in 240.81 and 240.83.

So according to the NEC, circuit breakers can be used as switches with some provisions.

240.81 Indicating. Circuit breakers shall clearly indicate whether they are in the open “off” or closed “on” position. Where circuit breaker handles are operated vertically rather than rotationally or horizontally, the “up” position of the handle shall be the “on” position.

240.83 Marking. (D) Used as Switches. Circuit breakers used as switches in 120-volt and 277-volt fluorescent lighting circuits shall be listed and shall be marked SWD or HID. Circuit breakers used as switches in high-intensity discharge lighting circuits shall be listed and shall be marked as HID.

If the circuit breaker clearly indicates the "on" and "off" position ("on" being up in vertically oriented situations), and the breaker is labeled "SWD" and/or "HID". Then the circuit breaker can be used as a switch, as far as NEC is concerned.

 

That breaker you so casually "flip on and off" will not last long. They are not made for constant movement.

 

i think the point is, 'how much electricity does the evse use when not charging'?

 

Ok, I’ve finall located my Kill-A-Watt meter and plugged the supplied EVSE through it. Without a load, these are my readings.

Watt = 0.5
Amp = 0.02
Volt = 3.0
kWh = 0.11
PF = 0.17 (don’t recall what PF stands for)

 

well done! i was off by 250%.