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Please help me figure out my charging costs

mojojojo_1

New Member
Sep 28, 2021
2
0
San Diego
Hello, i need help on ways to reduce my Tesla mpg cost. My math estimates that I am paying a $15 per gallon equivalent.
I have a model 3 long range delivered on 7/13. I have driven it 1,261 miles.

My electric bills in may was 82.43 in June it was 84.16 and in July it was 118.29

In July I was keeping it unplugged in my garage but to be prepared for a long trip and Reading online that it is good for the battery I started to leave it plugged in.

My august electric bill was 330.37 and in September it was 365.38!

So here is my quick math
1,261 miles / 2.5 months = 504.4 miles a month
Additional electricity cost to charge the Tesla per month is 252.91
(330.37 + 365.38 /2= 347.87 new electric average cost (82.43+84.16+118.29/3= 94.96 old average)

Total cost per mile is .200 and when I compare to my 09 Honda which gets 30 miles to the gallon it cost it is approx 15.04 a gallon.

I did a Tesla super charger which cost $20 for approx 140 miles of range which I estimate a $4.3 per gallon equivalent

I use the basic wall charger. I am not sure but i think it takes 36 hours to charge from 10% to 80-90
I have tried to set charging during off peak times but I think I set a trip timer where it stops charging at that time.


What can I do? Has anyone else worked out this math? I am worried I don’t drive enough to make the Tesla make sense.

I live in San Diego.
Tldr how do I drop my charging costs.
 
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Sandor

Member
Dec 12, 2019
69
116
SoCal
Hello, i need help on ways to reduce my Tesla mpg cost. My math estimates that I am paying a $15 per gallon equivalent.
I have a model 3 long range delivered on 7/13. I have driven it 1,261 miles.

My electric bills in may was 82.43 in June it was 84.16 and in July it was 118.29

In July I was keeping it unplugged in my garage but to be prepared for a long trip and Reading online that it is good for the battery I started to leave it plugged in.

My august electric bill was 330.37 and in September it was 365.38!

So here is my quick math
1,261 miles / 2.5 months = 504.4 miles a month
Additional electricity cost to charge the Tesla per month is 252.91
(330.37 + 365.38 /2= 347.87 new electric average cost (82.43+84.16+118.29/3= 94.96 old average)

Total cost per mile is .200 and when I compare to my 09 Honda which gets 30 miles to the gallon it cost it is approx 15.04 a gallon.

I did a Tesla super charger which cost $20 for approx 140 miles of range which I estimate a $4.3 per gallon equivalent

I use the basic wall charger. I am not sure but i think it takes 36 hours to charge from 10% to 80-90
I have tried to set charging during off peak times but I think I set a trip timer where it stops charging at that time.


What can I do? Has anyone else worked out this math? I am worried I don’t drive enough to make the Tesla make sense.

I live in San Diego.
Tldr how do I drop my charging costs.
Okay, lets try it to make sense. You have a lot of errors/inefficiencies here

First: you're comparing June/July with August/September. Let's just say that it was way hotter for San Diego in August/September this year than in June/July (I am in the area too). So your AC (or at least cooling via fan) costs are bigger. Plus days are shorter so more light usage too.

Second: Math is wrong. $0.20/mile means $6 for 30 miles (what your old Honda did on one gallon). So that would $6/gallon equivalent even if you did not had the error in cooling/light usage costs
CORRECTION: your math was $0.50/m (504.4 miles for $252.91 cost) not $0.20 which gets the $15/gallon; typo not math error

Third: SDGE energy costs are a lot more if you charge during peak times vs super off-peak. As in 6 times more on some plans ( $0.09 vs $0.56). If you charge during the day you are really subsidizing them. Charge ONLY midnight to 6am (or when your plan is cheapest). There are ways to help the car stop by switching off the outlet. Program the car to start charging at midnight. With the kind of miles you're driving it should be plenty of time to recover the charge used daily

Fourth: Sounds to me that you're using the basic 5-15 adapter with your mobile charger (if it takes 36h for 10 to 90%). That is horrifically inefficient. SDGE loves you (see above) as you are likely getting 1 kWh charge in the battery for 1.5kWh from the grid. Very likely you have at least a 240V outlet for an electrical dryer in your garage. Get the adapter for it from Tesla and use it. That will increase your efficiency dramatically AND get the car fully charged during the super off-peak hours.

I think you see where I am going... IS NOT the car but the way you're charging plus math errors. Myself, ignoring the savings from solar, I am roughly getting $0.04/mile equivalent (or $1.20/gallon vs your old Honda) in the same area where you live... M3-LRAWD too

Also, check to see if you have additional marginal energy consumption: race car-like driving, sentry mode on, cabin temp protection, under inflated tires, etc. This forum should help with details. But honestly that's noise vs your consumption

Hope it helps
 
Last edited:

jjgg

Member
May 21, 2021
263
323
Vancouver
Fourth: Sounds to me that you're using the basic 5-15 adapter with your mobile charger (if it takes 36h for 10 to 90%). That is horrifically inefficient. SDGE loves you (see above) as you are likely getting 1 kWh charge in the battery for 1.5kWh from the grid. Very likely you have at least a 240V outlet for an electrical dryer in your garage. Get the adapter for it from Tesla and use it. That will increase your efficiency dramatically AND get the car fully charged during the super off-peak hours.
Mobile connector with 5-15 is a bit less efficient than 240V but it is not as bad as you imagined. In the past few months I got about 84% efficiency with 5-15. So you would consume less than 1.2 kWh to put 1 kWh into the battery.
 

Tam

Well-Known Member
Nov 25, 2012
9,726
8,877
Visalia, CA
...how do I drop my charging costs...

I have SCE and they have a comparison of the rates taking in consideration of your past usage and compare that with the addition of your EV usage and which would be the most economical plan.

If you use very little, then it's cheapest with a tier system (cheapest when useless, extremely expensive when you use the most).

If you use a lot, then Time of User would be best so you can time your usage and use the most with the cheapest rate during the off-peak time and avoid as much as possible for all household use including EV during the peak time.

Same with many Superchargers in CA. Very expensive in Peak-Time but much cheaper in Off-Peak Time.
 
Last edited:

stopcrazypp

Well-Known Member
Dec 8, 2007
11,133
6,269
Tldr how do I drop my charging costs.
As others mentioned, the bump in electricity costs may not necessarily all be from car charging, but may be from change in demand from comparison of different seasons. You can avoid this somewhat by comparing YoY instead (this August vs previous August etc), although Covid may have thrown a monkey wrench on such comparisons.

Also, comparing dollars may hide other changes in your rates. You should instead compare changes in kWh usage, look at the exact rates you are paying (is it in tiers? is there TOU rates, etc). Just doing a blind dollar comparison doesn't really help address if it's really your car.

As for general help to take advantage of the best rates, see the Off Peak charging setting on page 157. You can take advantage of that and the various other settings (in combination of customizing your target percentage) to limit your charging times to the best rate for your utility.
https://www.tesla.com/sites/default/files/model_3_owners_manual_north_america_en.pdf

Note you can do a sanity check, if you never reset your trip meter (I intend to never do so for one of them), you can view your lifetime kWh and see if it matches with your calculations. You can use a 80% factor to account for rough energy loss converting AC to DC.

To exclude supercharger kWh from your calculation, you can go to your Tesla account, click Dashboard, Charging and the last page will have the years listed and you can download CSV files for every month. Inside will have kWh even if your charge was free for that session (as it may be if you have referral miles).

If instead you already reset the trip meter, you can try doing the calculation starting now with a new trip meter for the coming month. This will give you a far better account of your costs, instead of play guessing games on what's actually your car usage vs your home.
 

Tam

Well-Known Member
Nov 25, 2012
9,726
8,877
Visalia, CA
...I did a Tesla super charger which cost $20 for approx 140 miles of range which I estimate a $4.3 per gallon equivalent..

I think off-peak San Diego Tesla Supercharger rate is $0.21 / kWh

Peak San Diego Tesla Supercharger rate is $0.42 / kWh

I've heard your battery size is about 75kWh per Elon's tweet but let's round it up to 80 kWh and it's rated for 353 miles.

So each fill-up cost $0.21 / kWh x 80 kWh = $16.80 Off-peak

So each fill-up cost $0.42 / kWh x 80 kWh = $33.60 Peak

Since each full battery is rated for 353 miles, so:

$16.80 Off-peak full battery / 353 miles = $0.05 / mile

$33.60 Peak full battery / 353 miles = $0.10 / mile

Since your Honda is rated at 30 miles / gallon:

Off-peak $0.05 / mile x 30 miles = $1.43 / gallon

Peak $0.10 / mile x 30 miles = $2.86 / gallon
 
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srs5694

Active Member
Jan 15, 2019
1,276
1,588
Woonsocket, RI
I concur with what others have written, and especially @stopcrazypp and @Sandor. Key points (and a few more, at the end):
  • Compare charging in kWh, not dollars, at least as a first pass. Your electric bill should state how many kWh you consumed, in addition to the total costs.
  • Consider ToU rates. As others have said, if you're charging at expensive times of day, you'll pay more.
  • If ToU is an issue and you're charging at 120v, you'd do well to install a 240v outlet, or use an existing one, and setting charge timers in your car to control costs.
  • Consider what else might be consuming power. I once had a refrigerator go berserk and double my electric bill for a month or two.
  • New point: Some third-party apps and Web sites, such as TeslaFi, will help track charging sessions -- how much electricity your Tesla is consuming and when.
  • New point: Some third-party EVSEs, such as the Enel-X JuiceBox and the ChargePoint Home Flex, are network-connected and so can help you track consumption while charging, similar to what TeslaFi or other Tesla-specific apps can do. You say you use the "basic wall charger," and if by that you mean you've installed Tesla's Wall Connector, you probably don't want to replace that, so monitoring with a third-party app would make more sense. (Your 36-hour time to charge from 10% to 80% sounds more like a Level 1 speed, though, which suggests you're using the Mobile Connector that came with the car.) A variant would be to install a separate electric meter for the EVSE (whatever it is).
  • New point: If you suspect a specific appliance, or if you've ruled out the Tesla as the source of the problem via TeslaFi or something similar, then you might consider buying an energy-monitoring tool, such as the Kill-a-Watt meter. There are also whole-house tools that try to identify specific devices by their usage patterns, but I know less about them. However you do it, these tools can help you identify appliances that are using too much power. (Something like the Kill-a-Watt is limited to 120v devices, so it won't be good for identifying problems with a whole-house air conditioner or clothes dryer.)
 

Sunny5280

Member
Jul 29, 2021
149
96
Colorado
A lot of information here but in the end it costs what it costs to charge the vehicle. About the only control you have is to charge at lower rates if that option is available to you (i.e. at night if rates are lower). Otherwise I wouldn't concern myself with it and just enjoy the car.
 

SaintMickey®

Closed
Sep 19, 2021
117
56
USA
I just drive it and enjoy it...life is too short to worry about gas for cars or juice for my Tesla. That's no way to live...

Having said that...the Tesla makes it real easy to not worry...it costs us $3 for charging at home overnight from approx 20% or less to 100%.

IMG_4733.jpeg
IMG_4734.jpeg
 

srs5694

Active Member
Jan 15, 2019
1,276
1,588
Woonsocket, RI
A lot of information here but in the end it costs what it costs to charge the vehicle. About the only control you have is to charge at lower rates if that option is available to you (i.e. at night if rates are lower). Otherwise I wouldn't concern myself with it and just enjoy the car.
With all due respect, @mojojojo_1 is reporting an increase of over $250/month in their electric bill. That's in the same neighborhood as car loan payments, depending on the car, down-payment, loan term, etc. It's well beyond the "ignore it and have fun" cutoff for expenses.
 

SaintMickey®

Closed
Sep 19, 2021
117
56
USA
With all due respect, @mojojojo_1 is reporting an increase of over $250/month in their electric bill. That's in the same neighborhood as car loan payments, depending on the car, down-payment, loan term, etc. It's well beyond the "ignore it and have fun" cutoff for expenses.

LOL no way our electric bill is going up more than $20 a month. That's cra cra.
 
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jjrandorin

Moderator, Model 3, Tesla Energy Forums
Nov 28, 2018
11,562
13,486
Riverside Co. CA
With all due respect, @mojojojo_1 is reporting an increase of over $250/month in their electric bill. That's in the same neighborhood as car loan payments, depending on the car, down-payment, loan term, etc. It's well beyond the "ignore it and have fun" cutoff for expenses.
That would depend on what someone was paying for gas. Premium gas in the area that this OP is in (san diego) is $4.50 a gallon. The increase in Electric use has a corresponding removal of purchasing Gas.

They also are comparing electric use likely in a tiered electric system and may have been bumped up to the top rate from a lower rate due to use. There isnt enough information here to help the OP figure it out, but even if they have $250 more in electric usage, they likely have at least 1/2 that in a reduction in gas.
 
I get a TOU (time of use) rate of $0.0868 per kWh. With my Nissan Leaf at 3.7 miles per kWh it worked out to about $0.0234 per mile. Considering the greater efficiency of my model 3SR+ it is probably even less than that. Probably about $0.02 per mile.

I have no idea what the OP is paying for a rate but those numbers they posted make no sense.
 
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Sunny5280

Member
Jul 29, 2021
149
96
Colorado
With all due respect, @mojojojo_1 is reporting an increase of over $250/month in their electric bill. That's in the same neighborhood as car loan payments, depending on the car, down-payment, loan term, etc. It's well beyond the "ignore it and have fun" cutoff for expenses.
And? If driving his car resulted in an additional $250/month in his electric bill what can he do to change it? Unless he suspects a fault in the vehicle which is drawing more power than it should the only thing he has control of is charging at a lower tier (if that's an option). Otherwise it costs him $250/month more to drive his car.
 
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Reactions: srs5694

srs5694

Active Member
Jan 15, 2019
1,276
1,588
Woonsocket, RI
LOL no way our electric bill is going up more than $20 a month. That's cra cra.
You're in Atlanta (Georgia, I presume). The electricity plans in California are very different -- electricity is pricier, and various tiered plans are common there. (I don't know if they're common in Georgia.) I don't have the details of the plans in @mojojojo_1's area at my fingertips, but a $250/month increase doesn't strike me as inconceivable if @mojojojo_1 is on the wrong electric plan and/or is doing something wrong (like charging at high-rate times of the day).
Premium gas in the area that this OP is in (san diego) is $4.50 a gallon. The increase in Electric use has a corresponding removal of purchasing Gas.
True; however, @mojojojo_1 reports having driven a total of 1,261 miles over about two and a half months. A 30 mpg car, at $4.50 a gallon, would have cost $189 to fuel for that many miles. The excess electricity costs that @mojojojo_1 is reporting total about $560, give or take a bit, over that period. IF that's due exclusively to the car's electricity consumption, it's well in excess of what a comparable gas car would cost, and enough to be beyond the "ignore it and have fun" boundary (although the latter is subjective, so maybe not for everybody).
There isnt enough information here to help the OP figure it out
Agreed; but most people here have either been posting hypotheses or asking for the additional information required to help get to the bottom of the problem. As numerous posts earlier in this thread suggest, the problem might not be exclusively with the car; and if it is, there are almost certainly solutions better than the "ignore it and have fun" reply to which I was objecting.
 

srs5694

Active Member
Jan 15, 2019
1,276
1,588
Woonsocket, RI
And? If driving his car resulted in an additional $250/month in his electric bill what can he do to change it? Unless he suspects a fault in the vehicle which is drawing more power than it should the only thing he has control of is charging at a lower tier (if that's an option). Otherwise it costs him $250/month more to drive his car.
Rather than throw your hands up in defeat, or object to those who object to that reaction, how about offering @mojojojo_1 some suggestions?
 
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So, I just went to the website of the power provider for the San Diego area. They offer a special TOU rate for EV drivers of $0.09 per kWh from midnight to 6:00 AM. There is also a $16.00 per month service charge for that plan.

Something is wrong with that picture. Does not make sense. The OP may need to do some more homework.
 

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