Easy way to measure Nema 5-20 120v energy consumption?

[gsmith123]

I currently charge off a Nema 5-15 120v plug at 12A. I have a roommate and I need to pay for car charging, so I'm charging through a Kill A Watt style meter. Works totally fine for at 12A and makes it easy to know exactly how much energy charging is using, including losses, preheating, etc.

There's a Nema 5-20 120v plug available as well (20A plug). I'd like to use this, but i can't finding any easy ways to measure the energy usage. Any suggestions?

12A is more or less enough to cover my driving, so I don't really needs this but if I could make it as convenient as my current setup that would be nice...

 

[RayK]

Is the problem that the Kill-A-Watt meter is limited to a maximum of 15A for current (power) measurement?

Or is the problem more simple: not being able to put a NEMA 5-15 plug into a dedicated 5-20 outlet? If that's the case, there's probably an adapter available somewhere.

edit: To clarify, a 5-20 outlet can provide up to 16A continuous. A 5-15 outlet is rated at 12A. A typical NEMA 5-20 outlet should be able to accept a 5-15 plug (that's the sideways T in the outlet).

 

[gsmith123]

The kill a watt device has Nema 5-15 plugs, both the male and female sides. I know physical adapters exist to connect a Tesla 5-20 adapter through to the 5-15 receptacle on the device, to let the EVSE think it's connected to a 5-20.. However, none of that is rated for 16A continuous. Would it work? Probably... but I would ideally like a meter that's rated for 16A.

 

[ATPMSD]

I do not think they make a 20A version and it would be unwise to attempt to use this on a 20A circuit. You may need to go to something like this:

Sense.com – The Sense Home Energy Monitor

sense.com

 

[SourJellybeans]

Out of curiosity, why don’t you just go off the charge stats in the Tesla app? I assume the values are after-transmission-losses but I assume you could just apply a multiplier like 10% to that and be “close enough”, and the difference would be under the cost of more sophisticated measurement tools.

 

[ucmndd]

Out of curiosity, why don’t you just go off the charge stats in the Tesla app? I assume the values are after-transmission-losses but I assume you could just apply a multiplier like 10% to that and be “close enough”, and the difference would be under the cost of more sophisticated measurement tools.

This is the answer.

 

[webfootguy]

Pay for a teslafi.com account. Charge stats give you the exact amount used for each charge.

 

[DuncanM]

I currently charge off a Nema 5-15 120v plug at 12A. I have a roommate and I need to pay for car charging, so I'm charging through a Kill A Watt style meter. Works totally fine for at 12A and makes it easy to know exactly how much energy charging is using, including losses, preheating, etc.

There's a Nema 5-20 120v plug available as well (20A plug). I'd like to use this, but i can't finding any easy ways to measure the energy usage. Any suggestions?

12A is more or less enough to cover my driving, so I don't really needs this but if I could make it as convenient as my current setup that would be nice...

You can use a clamp meter:

https://www.amazon.com/Current-Amperage-Voltmeter-Multimeter-Transformer/dp/B07JB9B2QL/

 

[Vegas_Dubbz]

You can use a clamp meter:

https://www.amazon.com/Current-Amperage-Voltmeter-Multimeter-Transformer/dp/B07JB9B2QL/

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