How to monitor amount of electricity going through my NEMA 14-50

[mrod1975]

Hello,

Does anybody here have a method of monitoring the amount of electricity going through their NEMA 14-50 outlet on a daily, weekly, and monthly basis? I am looking to know how much electricity I'm putting into my Model S.

Thanks!

Martin

 

[gregd]

I believe the MS/X can report on its charging history, but if you want an independent measure, you'll obviously need something with a meter and logging. I am using an OpenEVSE wall charger, which has a built-in display for such things. I haven't tried it, but there's a Wi-Fi adapter option that can connect it to your network, presumably for additional monitoring and/or logging.


Some folks have tried one of those whole-house monitoring systems that connect at the meter, and which try to deduce what things are being run. Great concept, and simple install, but decidedly mixed results were reported. There's a thread on the subject in this subforum from a while ago.

 

[Tam]

There's an article that hardwires a meter inline between the source and the outlet:

Measuring EV charging efficiency - Tesla Living

If you know how to work with the main electrical panel, there are:

$220 Neurio

$130 Efergy E2

I am scared of being electrocuted so I just pay TeslaLog.com to retrieve the data from my car:

Monthly report:

Detail report:

22:41 - 00:22 - Visalia - 21.5/23.5kWh 91% eff. 247V 72A 80/80% Complete

That means I pay for 23.5 kWh but my battery only got 21.5 kWh so I lost 9% and it's 91% efficiency.

 

[Haxster]

Hello,

Does anybody here have a method of monitoring the amount of electricity going through their NEMA 14-50 outlet on a daily, weekly, and monthly basis? I am looking to know how much electricity I'm putting into my Model S.

Thanks!

Martin

www.youtube.com/watch?v=Tc8jErJ28hQ
www.amazon.com/gp/product/B015PRF04I/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

 

[swaltner]

These are all good solutions. As mentioned by others, it boils down to a few different options. Each type of monitoring has benefits and drawbacks and your use case:

- Monitor power in the breaker panel or on the way to the outlet/EVSE. I personally like TED (The Energy Detective), but many others are available. Neurio, Efergy, Sense, or simply an old-school electric meter wired in-line like the Tesla Living article outlined. My understanding is that these devices tend to be the most accurate. The main issue is that if you have multiple vehicles charging, you can't automatically attribute a single charge session to a specific vehicle. These tend to be very simple to use and can be installed for a couple hundred dollars as a one-time purchase.

- Monitor power in the EVSE. As mentioned, the OpenEVSE does this. It displays a running total of the Wh delivered in the current charging session and the kWh delivered over the life of the unit. The caveat is that at least for some of their units, there is no voltage measurement, so they make this calculation assuming a stable 120V or 240V supply, which is not the case. You also can't automatically attribute a specific charging session to a specific vehicle. If you don't have your charging solution in place already, with the proper EVSE purchase, this could be a no-additional-cost solution (initial or on-going).

- Monitor power in the car using the Tesla API with something like TeslaLog.com. This has the benefit of no upfront cost, but does have an ongoing subscription cost. This could be avoided if you run the monitoring on your own home-based servers that are already have running 24-7. This would isolate charging sessions across multiple vehicles that you have in your household fleet and would also keep track of charging sessions that are away from the home where the other two forms of charging. This would include Superchargers, Destination charging, workplace charging, really anything away from the home. I don't know how these services handle charging sessions when the car is parked somewhere without cellular service (underground parking garage for example). That may or may not be an issue for your use cases.

 

[tga]

Old school - install (or have your electrician install) a meter in line with your outlet. You can get a meter pan and refurbished revenue-grade meter for ~$50 here - Hialeah Meter Company

 

[Pricee2]

I use the "Efergy Elite 4.0" available from Amazon. Not cheap but is wireless and stores your usage for a full year.

 

[SDRick]

I use the $20 4 in 1 digital meter from Amazon. Works well!

 

[mrod1975]

SDRick, do you have a link to the meter and pics of your installation available? I'm very curious !

 

[SDRick]

SDRick, do you have a link to the meter and pics of your installation available? I'm very curious !

As posted by Haxter. www.amazon.com/gp/product/B015PRF04I/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

May be less on eBay.

 

[SchaF]

For those who are using a simple cheap meter from amazon, how are you wiring the meter for power? Im going to have 6 gauge wire for my NEMA 14-50 outlet, but I dont want to run the 6 gauge wire directly into the meter. So how can I wire it up?

 

[ccdisce]

You will need to tap into the 240V with 18AWG 600V wires and run that back to the meter. I would crimp ferrules at the ends of the 6AWG adding a 18AWG wire to L1 and another to L2.

The peacefair pzem-004 comes with a current sensor that can be placed in the outlet box. it has to go around a hot leg L1 or L2

somewhere , the box is a suggested location for it so you will need to run another wire wire pair back to the meter.

After wrestling with the receptacle wires to stuff them in the box please check that the screws that are holding the wires to the receptacle are tight.

 

[SchaF]

Ok so basically run Leg1 through the CT sensor on the way to the 14-50 outlet, and then I would need 2 18awg wires (say red and black) to connect to the energy monitor, and run the black connected with Leg1 in the 14-50 socket and red with leg2 in the 14-50 socket?

Im read online elsewhere that if you run one of the wires powering the energy monitor from the 14-50 outlet back through the CT, it should zero out any residual draw so unless its pulling something, it should read zero.

 

[tga]

I would put in line fuseholders on the lines feeding the meters. I would not trust a no-name cheap meter to not lose its mind and short out the power feed.

I wouldn't worry about the meter's draw effecting your results; it's negligible

 

[ccdisce]

Ok so basically run Leg1 through the CT sensor on the way to the 14-50 outlet, and then I would need 2 18awg wires (say red and black) to connect to the energy monitor, and run the black connected with Leg1 in the 14-50 socket and red with leg2 in the 14-50 socket?

Im read online elsewhere that if you run one of the wires powering the energy monitor from the 14-50 outlet back through the CT, it should zero out any residual draw so unless its pulling something, it should read zero.

Correct.
You get a wiring diagram with the device, copy shown here at:
PeaceFair Pzem-004T Energy Meters

Have not seen that, neat trick as I have noticed the minimal non-zero output reading, I will give it a try on the next one that I am currently building. On this oneI am attaching a esp32 WiFi card to make it readable from my Laptop.

 

[ccdisce]

I would put in line fuseholders on the lines feeding the meters. I would not trust a no-name cheap meter to not lose its mind and short out the power feed.

I wouldn't worry about the meter's draw effecting your results; it's negligible

The need for a fuse IMHO could be valid as I have seen on the web, doubts expressed over the AC isolation built in to the design.
If I were to add fuses in line, a leaded ceramic fuse 400-500VAC is what I would use.

 

[Benjanos]

+1 Efergy. I have two measurements, one for the house and one for the car.

Home of Energy Monitoring | Efergy

 

[jchag]

I have a SmartThings hub for home automation and I put a power meter on the leads going to my charger. Works perfect. Power meter cost $20 and the hub runs about $100

 

[Letmee]

I have a SmartThings hub for home automation and I put a power meter on the leads going to my charger. Works perfect. Power meter cost $20 and the hub runs about $100

Which Power Meter did you use? Aeotek by Aeon is $94.95 at amazon.

 

[lvrouter]

I have an extensive power monitoring system on my house which records usage for each of the 220 volt circuits individually (ACs, oven and EV Charging). Looking back at the history of the amount used on the EV circuit and comparing it to results from TeslaSpy.com which tells me how many kWh are added each night I can provide some useful numbers. I generally charge to 90% daily. TeslaSpy.com reports that the charging process is, on average, about 85% efficient. In other words 10kWh from the outlet translates to about 8.5kWh in the car. The energy that TeslaSpy indicates I've used during charges matches up +/- 1% with what my monitoring system reports.

With all of that said, TeslaSpy is much less expensive than the monitoring systems I've seen and appears to be very accurate.