Charging tesla at home with accurate cost

Joined
May 9, 2016
Messages
20
Location
England
Tesla Owner
No
Country
Country
#1
I wonder to ask questions and talk about it after I watched video of BMW i3 and real cost of charging the car in your garage, can Tesla do something like that?
You plug in your electric car in your garage and after months driving and getting juice for your car your electric bill will go up. BMW installed electric meter to get very true reading what you consume, and you can easy workout how much you paid for your electric car.
That will be great if tesla including something when you charge at home and connect to your tesla car app will add numbers x cost of you electric rates giving you True cost of charging your car and when you charge in super charger will show you what you save,
Months or year later you will see exactly your usage, cost and savings.
What you think?

 

Attachments

TrevP

TOO Founder / Administrator
Founder
Joined
Mar 1, 2016
Messages
6,555
Location
Toronto
Tesla Owner
Model X
Country
Country
#2
There are small meters you can install for such things. I'll be researching them when it comes time to install our charger in the garage. Since I have a separate panel in there it should be easy to monitor consumption.
 
Joined
May 9, 2016
Messages
20
Location
England
Tesla Owner
No
Country
Country
#3
There are small meters you can install for such things. I'll be researching them when it comes time to install our charger in the garage. Since I have a separate panel in there it should be easy to monitor consumption.
That something, what you think about including that information on your Tesla app ? Tesla will update the app one day what they working nobody know but that kind of information I would like to have
 

TrevP

TOO Founder / Administrator
Founder
Joined
Mar 1, 2016
Messages
6,555
Location
Toronto
Tesla Owner
Model X
Country
Country
#4
I believe the Tesla app does currently show the kW and voltage pull when charging.

I'd like something that perhaps has the ability to be queried, say over wifi, and the data stored for analysis. I'd write an app or something to keep tabs on consumption.
 

teslaliving

Top-Contributor
Joined
Apr 2, 2016
Messages
556
Location
Boston
Tesla Owner
Model S
Country
Country
#6
I use an EKM Meter on my Model S.:
img_2965.jpg
The Model S reports energy used but it can't account for charging inefficiency, vampire drain etc. The EKM Meter gives you a real read of usage.

There are other ways of doing this like Smappee, etc which may also do the trick but its a bit quirky in terms of output/interface:
Screen Shot 2016-05-23 at 6.15.56 PM.jpg

For me the dash reading is 86% of the actual. So you could just add 15% to what your car is reporting and be pretty accurate although things could vary depending on your driving etc.

Also, for more info:
http://teslaliving.net/2014/07/07/measuring-ev-charging-efficiency/
 

TrevP

TOO Founder / Administrator
Founder
Joined
Mar 1, 2016
Messages
6,555
Location
Toronto
Tesla Owner
Model X
Country
Country
#7
Thanks for the great report and post. I'll keep that in mind for ours!
 
Joined
Jun 19, 2018
Messages
21
Location
Toronto
Tesla Owner
Model 3
Country
Country
#9
For me the dash reading is 86% of the actual. So you could just add 15% to what your car is reporting and be pretty accurate although things could vary depending on your driving etc.

Also, for more info:
http://teslaliving.net/2014/07/07/measuring-ev-charging-efficiency/
I was always wondering what the efficiency of charging EV battery is, and that the true cost can't be calculated by using the kWh/km that Tesla shows on the display. I knew it couldn't be 100%, but wasn't sure the exact number. Thanks!
 

Ed Woodrick

Top-Contributor
Joined
May 25, 2018
Messages
596
Location
Atlanta, GA
Tesla Owner
Model 3
Country
Country
#10
Do you keep a detailed chart of how much gas you currently use? If not, why start now?

It's real easy to get a good estimation of the cost of electric charging vs average cost of gas. But does it really make a difference aside from bragging rights?

It's really hard to get a good handle on the actual cost of gas, with the price changing daily, you have to actually record the cost and amount and the times that you would fill up. Since you don't fill an electric and gas at the same time, detailed comparisons are hard.

For electrics, your price is basically going to be Total Miles / 4miles/kWh *cost of electricity.
12,000 miles / 4 * $0.10 /kWh = $300
4 miles / kWh = 1/ 250 watts/mile (a Tesla average)

If you are on time of day rates, then they do change during the day (and any metering solution must be able to account for this) but I think that most areas have a winter rate and a summer rate, which dependent on the area, averages to some number, I used $0.10 / kWh
 
Joined
Jun 19, 2018
Messages
21
Location
Toronto
Tesla Owner
Model 3
Country
Country
#11
Do you keep a detailed chart of how much gas you currently use? If not, why start now?

It's real easy to get a good estimation of the cost of electric charging vs average cost of gas. But does it really make a difference aside from bragging rights?

It's really hard to get a good handle on the actual cost of gas, with the price changing daily, you have to actually record the cost and amount and the times that you would fill up. Since you don't fill an electric and gas at the same time, detailed comparisons are hard.

For electrics, your price is basically going to be Total Miles / 4miles/kWh *cost of electricity.
12,000 miles / 4 * $0.10 /kWh = $300
4 miles / kWh = 1/ 250 watts/mile (a Tesla average)

If you are on time of day rates, then they do change during the day (and any metering solution must be able to account for this) but I think that most areas have a winter rate and a summer rate, which dependent on the area, averages to some number, I used $0.10 / kWh
All we are saying is that what Tesla shows on the display is about 15% less energy than what you really put in the car, unlike gas engines where you don't have to adjust for that. Does it really make a difference? It makes about 15% difference. So, not a whole lot but it is not negligible either.