On-Off Switch for 249v 49 amp wall outlet for level 2 charger?

[dtbaker61]

I had one electrician tell me it would be better to switch the breaker on and off rather than plug and unplug every time.

as long as you don't flip it on/off under load while charging.... using the circuit breaker as a switch is fine for thousands of 'cycles'.

But, the charger on standby uses a minuscule amount of energy. Do you also unplug all your other charging devices and appliances when not in use?

modem-tv-stereo-computers use way more on standby... but still only a few watts. You'd save way more by driving the MME a few less miles.

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[JohnnyForensic]

Yeah, I’m in the “don’t do this” club for a couple of reasons.

1. The EVSE when unplugged or plugged in and not delivering power to the car uses almost nothing. Like, nothing. As you’ve seen above, we’re talking maybe $5/year nothing. When it’s not delivering power, it’s got a charge circuit listening for a connection and maybe an LED. It’s not/not pulling a huge amount of charging power and doing nothing with it.

2. If you do this, you’re now violating the ABC rule (Always Be Charging). When the MME is plugged in, after it reaches its required charge level, it doesn’t continually draw anything. It stops pulling current. The MME regulates its battery temperatures when it’s very hot or very cold from the battery itself. At some point in time, the MME will decide that it’s depleted enough of its battery doing this that you’re not topped off to the charge level you set, and it will automatically re-engage charging (but again, only if plugged in and the thing is powered up) to get you back that stolen 1% or so that was used to maintain the battery. That way, when you get to your car, your charge is where you expect it to be. You probably won’t draw much at all for thermal management on a 70º day, but you might see it pull a little bit a power once or twice a night when the temps drop closer to the teens.

Point being, if you have the EVSE disconnected, or you’re not always plugged in when you’re at home, you’re depriving yourself of an optimal experience for very, very little money involved. I’m not making this up. Looking at my ChargePoint graphs shows me in detail how much power is being drawn while plugged in over time, and you can see exactly where the small peaks and large valleys are when leaving it connected.