A good way of measuring accurately KWH usage?

[Zirak]

Hi all,

I live in a fairly small home (> 1500 sqft) and have noticed lately my electricity bill has been extremely high, 1991kwh for my last bill in Hamilton (one month usage). My commute is roughly 65km one way, majority being highway driving (Hamilton to Mississauga), and I usually top up my charge at work. So on a daily basis I'd be charging around 12~13kwh at home scheduled after hours, according to my car this is how much energy is used on my way back home.

My electrician is saying that it's likely my car sapping most of that electricity, but I'm highly doubtful, because if it even charges 15kwh a night for 5 days (and let's say 10kwh sat/sunday) that's about 95kwh a week, or almost 400kwh a month, but even subtracting that, I'd still be at 1600kwh usage. Was wondering if anyone has bought some sort of device that can monitor the power usage on each circuit? I was thinking maybe there's some sort of "smart" breakers that I can replace my existing breakers with, which would report this usage via WiFi or something...

Thanks in advance!

 

[Vawlkus]

Do much preheating? That doesn’t get captured by the car, but it’s still a drain.

I use an induction power meter on my charging circuit to track my usage.

 

[darkenergy]

That's definitely out of line.

Our place is similar. We do about 550 km per week mixed between our EVs and our monthly consumption is ~800 kWh. July and August are a bit higher for A/C. Heating is nat gas. Add in about ~250 kWh for partial charging at my wife's office and we'd still be barely over 1000 kWh.

 

[jsmay311]

If you're comfortable working inside your electrical circuit breaker panel, there are various home energy monitor devices that you can purchase that have current-measuring clamps that clamp around wires and can be used to measure usage for an entire home or just a single circuit.

I have one that measures my whole home and my EVSE circuit independently, but it's quite old. Maybe some others can recommend a newer product. Or you could browse home energy monitors on Amazon.

----------------------

Side note: Remember that the kWh hour figures shown on the screen only include energy used when the car is "in gear". So no vampire losses, no sentry mode, no preconditioning, no climate usage while parked, etc. And it also doesn't account for charging losses, which increase with cold temperatures due to battery heating power consumption.

So your actual home kWh usage will typically be significantly higher than the numbers shown on the car's screen. Exactly how much higher will vary with how the car is used and with your local climate. This one Canadian bloke in southern Ontario has kept detailed track of his usage over 1.5 years. Looks like his lifetime totals show the actual kWh usage to be ~25% higher than the car's screen numbers. And that figure is even higher during winter months.

My lifetime % overhead vs the screen in Chicago is 28.5%, and I don't ever use Sentry mode or Cabin Overheat Protection and I very rarely precondition.

 

[Webeevdrivers]

I don’t know about the new Tesla Wall charger but the Juicebox tracks and logs power in a variety of useful ways. Check out the new Tesla Wifi wall charger to see what it’s capabilities are. Otherwise consider a Juicebox.

 

[bijan]

I don't know what stats your power utility gives you but I can see hourly and daily consumption online with Oakville hydro. Just go and check days and hours that your car wasn't plugged in to see if there is another large draw that's unaccounted for.

I used this to see the draw of leaving the circulation fan on all the time vs only when my furnace is on for example.

 

[ewoodrick]

Hi all,

I live in a fairly small home (> 1500 sqft) and have noticed lately my electricity bill has been extremely high, 1991kwh for my last bill in Hamilton (one month usage). My commute is roughly 65km one way, majority being highway driving (Hamilton to Mississauga), and I usually top up my charge at work. So on a daily basis I'd be charging around 12~13kwh at home scheduled after hours, according to my car this is how much energy is used on my way back home.

My electrician is saying that it's likely my car sapping most of that electricity, but I'm highly doubtful, because if it even charges 15kwh a night for 5 days (and let's say 10kwh sat/sunday) that's about 95kwh a week, or almost 400kwh a month, but even subtracting that, I'd still be at 1600kwh usage. Was wondering if anyone has bought some sort of device that can monitor the power usage on each circuit? I was thinking maybe there's some sort of "smart" breakers that I can replace my existing breakers with, which would report this usage via WiFi or something...

Thanks in advance!

What does your normal winter usage look like? What was the difference in the last billed amount vs what it was over the last few years?

 

[5_+JqckQttqck]

Hi all,

I live in a fairly small home (> 1500 sqft) and have noticed lately my electricity bill has been extremely high, 1991kwh for my last bill in Hamilton (one month usage). My commute is roughly 65km one way, majority being highway driving (Hamilton to Mississauga), and I usually top up my charge at work. So on a daily basis I'd be charging around 12~13kwh at home scheduled after hours, according to my car this is how much energy is used on my way back home.

My electrician is saying that it's likely my car sapping most of that electricity, but I'm highly doubtful, because if it even charges 15kwh a night for 5 days (and let's say 10kwh sat/sunday) that's about 95kwh a week, or almost 400kwh a month, but even subtracting that, I'd still be at 1600kwh usage. Was wondering if anyone has bought some sort of device that can monitor the power usage on each circuit? I was thinking maybe there's some sort of "smart" breakers that I can replace my existing breakers with, which would report this usage via WiFi or something...

Thanks in advance!

Gas or electric heaters in the house? This winter's been colder than usual.

 

[TomLee]

I installed a dedicated meter for the charging circuit. I charged 375kWh and drove 1250kms so far in Jan as of 23rd. I'm in Vancouver and daily around 20km to 30km with few long drives in the holidays. For me, short drives uses a lot more energy to heat up the car repeatedly. I also found that trickle charge after finish charging does consume power (about 1kWh/15hr).

 

[wayner]

Does you local utility give detailed usage info on their website? With Toronto Hydro I can see my usage for each hour. So track that for a few nights - alternate nights between charging and not charging and look at your usage at 5am or whenever you start your scheduled charge. I can even download this data to a spreadsheet.

For me when not charging I use about 2.3kWh in the middle of the night. When I am charging I use up to 20 kWh in an hour - I charge at 70A. I have a big home and lots of electronics, plus an electrically heated hot tub.

 

[Zirak]

Do much preheating? That doesn’t get captured by the car, but it’s still a drain.

I use an induction power meter on my charging circuit to track my usage.

Yep, preheat every morning. But I charge at work too, so that shouldn't matter. I don't preheat when going back home.

If you're comfortable working inside your electrical circuit breaker panel, there are various home energy monitor devices that you can purchase that have current-measuring clamps that clamp around wires and can be used to measure usage for an entire home or just a single circuit.

I have one that measures my whole home and my EVSE circuit independently, but it's quite old. Maybe some others can recommend a newer product. Or you could browse home energy monitors on Amazon.

----------------------

Side note: Remember that the kWh hour figures shown on the screen only include energy used when the car is "in gear". So no vampire losses, no sentry mode, no preconditioning, no climate usage while parked, etc. And it also doesn't account for charging losses, which increase with cold temperatures due to battery heating power consumption.

So your actual home kWh usage will typically be significantly higher than the numbers shown on the car's screen. Exactly how much higher will vary with how the car is used and with your local climate. This one Canadian bloke in southern Ontario has kept detailed track of his usage over 1.5 years. Looks like his lifetime totals show the actual kWh usage to be ~25% higher than the car's screen numbers. And that figure is even higher during winter months.

My lifetime % overhead vs the screen in Chicago is 28.5%, and I don't ever use Sentry mode or Cabin Overheat Protection and I very rarely precondition.

Would I have to purchase a clamp device per circuit on my breaker? This is good info, I might consider purchasing this. Thanks!

I don’t know about the new Tesla Wall charger but the Juicebox tracks and logs power in a variety of useful ways. Check out the new Tesla Wifi wall charger to see what it’s capabilities are. Otherwise consider a Juicebox.

Already have a Tesla HPWC wired for 48amps that I purchased from a user from TMC.

I don't know what stats your power utility gives you but I can see hourly and daily consumption online with Oakville hydro. Just go and check days and hours that your car wasn't plugged in to see if there is another large draw that's unaccounted for.

I used this to see the draw of leaving the circulation fan on all the time vs only when my furnace is on for example.

I don't recall seeing this option on Alectra Utilities website, I'll take a closer look, thanks!

What does your normal winter usage look like? What was the difference in the last billed amount vs what it was over the last few years?

This is my first home I purchased (as of August 2019), so experiencing winter for the first time, no real history to go off of unfortunately. But the usage is definitely higher than the place I used to rent in Brampton, and the house was much larger too.

Gas or electric heaters in the house? This winter's been colder than usual.

Gas forced heat. The furnace is quite old, and might be breaking down, not entirely sure... sometimes it refuses to work for a few hours on end at least once a week or so.

I installed a dedicated meter for the charging circuit. I charged 375kWh and drove 1250kms so far in Jan as of 23rd. I'm in Vancouver and daily around 20km to 30km with few long drives in the holidays. For me, short drives uses a lot more energy to heat up the car repeatedly. I also found that trickle charge after finish charging does consume power (about 1kWh/15hr).

What does the meter look like, is this something I can purchase and install? Also, how much did it cost you? Thanks!

Does you local utility give detailed usage info on their website? With Toronto Hydro I can see my usage for each hour. So track that for a few nights - alternate nights between charging and not charging and look at your usage at 5am or whenever you start your scheduled charge. I can even download this data to a spreadsheet.

For me when not charging I use about 2.3kWh in the middle of the night. When I am charging I use up to 20 kWh in an hour - I charge at 70A. I have a big home and lots of electronics, plus an electrically heated hot tub.

Gotta take a look.

 

[Zirak]

Doesn't look like it gives you the option to see an hourly breakdown.
This is the closest I can get, which is just my usage per bill.

Apparently 98.43% of all the neighbours around me used less than me in consumption...

 

[bijan]

Alectra utilities website seems to imply they have the data on your account:

Time-of-Use: what you need to know

"How can I manage my Time-of-Use bill?
Simply login to My Account to see how much electricity your household consumes during each TOU period of the day. You will find easy-to-understand graphs of your usage for hourly, daily, weekly and monthly time periods. There are plenty of tools and tips to help you manage your household energy consumption, set consumption and energy cost alerts, and predict your next bill. Sign up today and join the close to 60,000 Alectra Utilities customers who have access to their information on-line."

Edit: look for a time of use section or tab that's where it is under in Oakville hydro assume it might be the same with yours

 

[Zirak]

Alectra utilities website seems to imply they have the data on your account:

Time-of-Use: what you need to know

"How can I manage my Time-of-Use bill?
Simply login to My Account to see how much electricity your household consumes during each TOU period of the day. You will find easy-to-understand graphs of your usage for hourly, daily, weekly and monthly time periods. There are plenty of tools and tips to help you manage your household energy consumption, set consumption and energy cost alerts, and predict your next bill. Sign up today and join the close to 60,000 Alectra Utilities customers who have access to their information on-line."

Edit: look for a time of use section or tab that's where it is under in Oakville hydro assume it might be the same with yours

Got it... lol I'm just blind. Going to go over the data, thanks!

 

[jsmay311]

Would I have to purchase a clamp device per circuit on my breaker? This is good info, I might consider purchasing this. Thanks!

If you just want to measure the circuit with the HPWC, you'd only need an energy monitor with 2 clamps -- 1 for each leg of the 240V circuit.

 

[cwerdna]

If what your utility provides is insufficient, does your utility have something like PG&E Stream My Data Folks on my Nextdoor community have talked about EAGLE-200 Energy Gateway - Rainforest Automation which is on the list at PG&E Han Device Validation | National Technical Systems.

Don't waste $ on something like that unless it's known to work w/your smart meter, if you have one.

 

[Zirak]

If you just want to measure the circuit with the HPWC, you'd only need an energy monitor with 2 clamps -- 1 for each leg of the 240V circuit.

Would something like this work?
https://www.amazon.ca/gp/product/B014W3D1OC/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

 

[jsmay311]

Would something like this work?
https://www.amazon.ca/gp/product/B014W3D1OC/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

Looks like it would.

One of the questions in the Q&A section asks if the single current meter clamp/ring would work with a 240V circuit, and the answers all said it would work fine -- which makes sense since the current through each leg of a 240v circuit should be the same.

However, one shortcoming is that the current-measuring device is a solid ring rather than a clamp that can be opened. So you'd have to disconnect the wire and pull it through. Not a big deal tho if you're comfortable doing electrical work and shut off power properly.

 

[SilverGS]

I'm interested in getting a device that can clamp on the 240V charging circuit in the electrical panel rather than the ring (noted above). If you know of one, please link it here. Thanks!

 

[EV-Fixme]

The amazon device does that, you have to slip the ring around on of the power cables, just 1 not both.