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I own a 2018 Volt and I have 3 roommates, meaning I have to split the electricity bill costs between the four of us. However, I have to first subtract an estimate of my electricity charging cost. One of my roommates has a space heater that she uses incessantly and another runs a business office from home so we are all ok with an estimate. I am trying to be as accurate as possible to be fair, though.

I drive all highway on the weekdays and typically get anywhere from 40-46mi on a full charge (sadly my commute is 44mi!).

I don't know how to calculate the cost of electricity but I have all my electric mileage, charging and bill cost data here.

11/2 - 1/10

ELECTRIC MILES: 1,641

KWH ON CHARGEPOINT: 97
MILES ON CHARGEPOINT:*277
*Their own mileage estimate

KWH ON SEMACONNECT: 17KWH
MILES ON SEMACONNECT:*51.2
*Their own mileage estimate

KWH AT HOME: ???
MILES AT HOME (8A outlet, 110V): 1312.8

ELECTRICITY KWH ON BILL: 1233.28
ELECTRICITY BILLS TOTAL FOR ALL DATES ABOVE: $410

My plan was to just figure out the KWH I used for those "miles charged at home" and divide that by the 1,233.28 we have on our bill. Whatever that percent comes out to is the percent I'd pay of the $410.

Please help if you can assist! Especially curious if I can lower the amount that I pay by switching to a 12A outlet (right now it takes me like 18hr to charge fully on the 8A, I have a dedicated circuit 12A outlet I could use its just less convenient in terms of how I park my car). But totally unsure of how current relates to KWH relates to cost. Thanks!!!
 

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I own a 2018 Volt and I have 3 roommates, meaning I have to split the electricity bill costs between the four of us. However, I have to first subtract an estimate of my electricity charging cost. One of my roommates has a space heater that she uses incessantly and another runs a business office from home so we are all ok with an estimate. I am trying to be as accurate as possible to be fair, though.

I drive all highway on the weekdays and typically get anywhere from 40-46mi on a full charge (sadly my commute is 44mi!).

I don't know how to calculate the cost of electricity but I have all my electric mileage, charging and bill cost data here.

11/2 - 1/10

ELECTRIC MILES: 1,641

KWH ON CHARGEPOINT: 97
MILES ON CHARGEPOINT:*277
*Their own mileage estimate

KWH ON SEMACONNECT: 17KWH
MILES ON SEMACONNECT:*51.2
*Their own mileage estimate

KWH AT HOME: ???
MILES AT HOME (8A outlet, 110V): 1312.8

ELECTRICITY KWH ON BILL: 1233.28
ELECTRICITY BILLS TOTAL FOR ALL DATES ABOVE: $410

My plan was to just figure out the KWH I used for those "miles charged at home" and divide that by the 1,233.28 we have on our bill. Whatever that percent comes out to is the percent I'd pay of the $410.

Please help if you can assist! Especially curious if I can lower the amount that I pay by switching to a 12A outlet (right now it takes me like 18hr to charge fully on the 8A, I have a dedicated circuit 12A outlet I could use its just less convenient in terms of how I park my car). But totally unsure of how current relates to KWH relates to cost. Thanks!!!
Each week day (Mon - Fri), assuming you fully recharge the Volt's battery overnight once you return home, it will use approx 17kWh to put 14.1kWh into the Volt's battery. If you drive less on the weekend you may only be using a fraction 1/3, 1/2 of 17kWh to recharge (Sat - Sun.)

The simplest way to figure your kWh cost at home is to take the total bill ($410) and divide it by the total kWh (1233.28) = $0.33/kWh for electricity. $0.33/kWh x 17kWh = $5.61 per week day for fully recharging ~ $28.05 per week, $121.55 per month (plus your weekend charging, still TBD).

The problem with using your estimated miles driven in EV mode that were charged at home is that the miles per kWh will vary with temperature, speed and road conditions. Still, the EPA estimate for the Volt is based on 3.76 miles per kWh (53/14.1), (53/17 or 3.12 miles per kWh if this includes charging losses). 1312.8 miles / 3.12 miles per kWh = 420.76kWh x $0.33/kWh = $138.85 per month (the difference between $138.85 and the earlier monthly estimate $121.55 is $17.30 (that is the estimated cost of your weekend charging.) So, if you offer to pay ~$140/month for your share of the electric bill for charging the Volt plus whatever your share was before you started charging the Volt that should be pretty close. (Example $410.00 - $140.00 = $270.00; $270 / 4 people = $67.50 per person. So your share would be $138.85, or approximately $140.00 + $67.50 = $207.50. Your share would be ~ $ 207.00, slightly more than half of the total electric bill.

You will spend 1/3rd less time charging using 120V and 12 amps than at 8 amps, the efficiency will be approximately the same. If you were charging at 240V and 16 amps the Volt will fully recharge in 4.5 hours, there is a measurable difference in charging efficiency using 240V (87% efficient versus 83% efficient using 120V), so maybe 5% more efficient using 240V, over time that could save you some money.
 

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I believe 8A 120V charging is ~80-82% efficient, so 14.1 kWh delivered is about 17 kWh at the wall. 240V 16A is in the ~mid-upper 80% range (depends on ambient temp and TMS operation mainly I think), so closer to 16 kWh at the wall. In really hot or cold temps, while plugged in the TMS will cycle, but I'd say it's lost in the noise (~0.5-1 kWh per day max I think).

If you're depleting the battery each charge, and getting roughly 43 miles per charge, you can say 1312/43 = 30.5 charges at home * 17 kWh = ~520 kWh * your total rate per kWh.

Sounds about right for charging at home most days.

12A charging might save you a couple of kWh, but it's lost in the noise. It will charge it faster though which is more convenient.

That's my rough estimate, and probably about as close as you can get with this level of data fidelity.
 

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If you were to have OpenEVSE level 2 charger, it would display session total kwhr and lifetime total kwhr.

Otherwise - 3miles/kwhr good ballpark (includes AC to DC charger loss). Subtract your chargepoint miles.
 

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Wow, your electric is expensive, ~33c/kWh!!! The national average is about 12c/kWh.

Basically, you average 43miles on a full charge for 14kWh, so 3 miles/kWh. Take 1313 miles charged, divide by 3, for 438 kWh. Add in 10% for lost charging efficiency, so 481kWh. Multiply by 33cents, for $159 for charging your Volt.

As the temps warm, your mileage will improve, so your cost of charging the Volt should be less.

Your per mile cost is 12cents.

Let's say you get 36mpg, what would be the equivalent for gas? $4.32 a gallon, to spend 12 cents a mile for gas, if you get 36mpg. So, you can see, your electric is brutal.
 

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Yeah, that seems very high for electricity. In other words it costs about 2x the price of gasoline to go the same distance... what's the point of having a hybrid? Gas is about $2.60 a gallon here. Did you contact your power company about off peak discounts for charging EV's?
 

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How is your roomie with the space heater calculating how much extra she's chipping in?? Your extra use is for sure less than hers, so . . . . .

Don
 

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How is your roomie with the space heater calculating how much extra she's chipping in?? Your extra use is for sure less than hers, so . . . . .

Don
Average room heater, 1500 watts/110vac= 13.6 amps. So the room heater used more electricity than your volt at 12 amps. If the heater is running continuously.
 

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Doing the math is fun but showing people the numbers on a Kill-a-watt meter can help get the data you need and you may only need a few months of data and average after that testing.

(using 120 volt for charging and short cord to the meter for a better socket fit )

only took one month to show condo board the cost - but I left the device up for 2 years .
 

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You should be able to view your charging details on mychevrolet.com. You can download a csv file by the week or month, and open it in a spreadsheet. Separate out the entries from the days and times that you were charging at home and sum the kwh column.
 

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Can a Kill-A-Watt be repeatedly used at such a high current? I thought they were more for ~800 watts continuous and less, but you could intermittently do more.
 

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Can a Kill-A-Watt be repeatedly used at such a high current? I thought they were more for ~800 watts continuous and less, but you could intermittently do more.
If you can convince your roommate to purchase a Kill-A-Watt and monitor the power usage of the space heater you would be able to estimate the daily, weekly and monthly cost of running the space heater.
 

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^^ THIS!!! ^^

You could try using a energy meter reader and multiply by an average or agreed upon electricity rate.

Poniie PN2000 Plug-in Kilowatt Electricity Usage Monitor Electrical Power Consumption Watt Meter Tester w/ Extension Cord https://www.amazon.com/dp/B0777H8MS8/ref=cm_sw_r_cp_api_i_R6xoCb9NFZPDF
THIS! I have one, and have been using it on the stock EVSE @ 120V/8A, 120V/12A, and 240V/12A with a 14-30 to 5-15 adaptor. You can get one on Amazon for $20, and with support for 110V to AT LEAST 248-250V (as my line is unloaded), it will accumulate your kWh usage throughout the month, which you can reset on demand. It'll show instant voltage, amps, watts, cumulative loaded time, cumulative usage, even the power factor! It supports sustained 15A, and although I've confirmed it WILL SUPPORT 16A for at least a few minutes, since the user manual advises against "sustained, unattended usage above 15A" and the unit was angrily indicating an overload at 16A, it ran for 10-15 minutes without any concerning level of heat.

Simply look at the accrued energy at the end of the month and multiply by your electric rate ($0.12-14 average I believe); FAR easier than all that estimation stuff!

EDIT: As far as the Kill-A-Watt/Ponii longevity goes, I'd have to believe they're good long-term. We have one we use at work that I know has been around for YEARS and is used for monitoring a lot of power equipment we have, but those only work @ 110-120V, so I had to get the Ponii because I knew I'd been using my stock EVSE @ 240V. I have ran mine to fully recharge my battery 1-2 times per day for the past few months, plus have ran it at 240V/16A limit a few times without issue.
 

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If you can convince your roommate to purchase a Kill-A-Watt and monitor the power usage of the space heater you would be able to estimate the daily, weekly and monthly cost of running the space heater.
Indeed; I noticed that in my house, simply changing all our bulbs from 60W incandecents to 8W LEDs, I saved more on my bill than it went up charging my car 1-2 times a day (although true, we have a LOT of lights...); she needs to track her usage as much as you need to track yours!
 

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You should be able to view your charging details on mychevrolet.com. You can download a csv file by the week or month, and open it in a spreadsheet. Separate out the entries from the days and times that you were charging at home and sum the kwh column.
I've found Onstar data to be inaccurate. Comparing with known usage from a Kill-a-Watt, it was frequently off by 30% or more, sadly.

VoltAP1 said:
Can a Kill-A-Watt be repeatedly used at such a high current? I thought they were more for ~800 watts continuous and less, but you could intermittently do more.
I used one for about 3 years like this. I used 8A (960W) unless I needed 12A, but I used 12A at least once or twice a week. It did end up dying on me after a few years, but for the price that's not too bad. The screen actually started going first, and I think that was more a function of being in outside temperatures (albeit in a waterproof box) than high current.

OP, just get a Kill-A-Watt, seriously... it makes this way easier. Yes, you have to remember to check and reset it every month and it'll die after a few years, but it's the best way to do this accurately.
 

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Each week day (Mon - Fri), assuming you fully recharge the Volt's battery overnight once you return home, it will use approx 17kWh to put 14.1kWh into the Volt's battery. If you drive less on the weekend you may only be using a fraction 1/3, 1/2 of 17kWh to recharge (Sat - Sun.)

The simplest way to figure your kWh cost at home is to take the total bill ($410) and divide it by the total kWh (1233.28) = $0.33/kWh for electricity. $0.33/kWh x 17kWh = $5.61 per week day for fully recharging ~ $28.05 per week, $121.55 per month (plus your weekend charging, still TBD).

The problem with using your estimated miles driven in EV mode that were charged at home is that the miles per kWh will vary with temperature, speed and road conditions. Still, the EPA estimate for the Volt is based on 3.76 miles per kWh (53/14.1), (53/17 or 3.12 miles per kWh if this includes charging losses). 1312.8 miles / 3.12 miles per kWh = 420.76kWh x $0.33/kWh = $138.85 per month (the difference between $138.85 and the earlier monthly estimate $121.55 is $17.30 (that is the estimated cost of your weekend charging.) So, if you offer to pay ~$140/month for your share of the electric bill for charging the Volt plus whatever your share was before you started charging the Volt that should be pretty close. (Example $410.00 - $140.00 = $270.00; $270 / 4 people = $67.50 per person. So your share would be $138.85, or approximately $140.00 + $67.50 = $207.50. Your share would be ~ $ 207.00, slightly more than half of the total electric bill.
But the $410 billing period above is 9 weeks, not per month. The monthly bill for power is working out to closer to $190. Something isn't right someplace.
 

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In MN, we can check out killawatt meters from the library. Your electric company may also have one to borrow. Be sure to measure the heater, too.
Otherwise, you could likely save money by getting an offpeak meter for the car.
Math says each full charge is around $1.50, but my experience is about $30/month for 6.5 full charges/week.
Being mindful of using electricity plus charging the car may be less than someone else who isn't mindful of using electricity and doesn't have a car.
 

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If you have electric heating for the house the GOOD news is the LEDs light now give out free extra heat for winter heating
Not sure where the crossover point is for changing from CFL to LED but I see a lot of stores in texas changing out the old long tube light to LED.

Kill-A-watt has an internal resetable fuse but best to use a high grade SHORT external -adapter ( cord ) so you do NOT plug them directly to a socket -- You get a better tight fit and less heat build up

This also makes it easer to view and program the unit with out sitting on the floor.
 

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I own a 2018 Volt and I have 3 roommates, meaning I have to split the electricity bill costs between the four of us. However, I have to first subtract an estimate of my electricity charging cost. One of my roommates has a space heater that she uses incessantly and another runs a business office from home so we are all ok with an estimate. I am trying to be as accurate as possible to be fair, though.

I drive all highway on the weekdays and typically get anywhere from 40-46mi on a full charge (sadly my commute is 44mi!).

I don't know how to calculate the cost of electricity but I have all my electric mileage, charging and bill cost data here.

11/2 - 1/10

ELECTRIC MILES: 1,641

KWH ON CHARGEPOINT: 97
MILES ON CHARGEPOINT:*277
*Their own mileage estimate

KWH ON SEMACONNECT: 17KWH
MILES ON SEMACONNECT:*51.2
*Their own mileage estimate

KWH AT HOME: ???
MILES AT HOME (8A outlet, 110V): 1312.8

ELECTRICITY KWH ON BILL: 1233.28
ELECTRICITY BILLS TOTAL FOR ALL DATES ABOVE: $410...
It seems to me that not all of your charging is done at your home, and that presents a problem with calculating your at home charging kWh.

IOW, you drove 1,641 ev miles and obtained 114 kWh of power to recharge what Chargepoint and Semaconnect estimated to total 328.2 ev miles. I suspect you subtracted that from the total, i.e., 1,312.8 ev miles is your estimate of the miles charged at home.

Driving 328.2 ev miles using 114 kWh gives a fuel economy of 34.7 kWh/100 miles. That could be in the ballpark. The window sticker rating is 31/100, and winter driving might increase that.

Multiplying the 1,312.8 miles recharged at home by that rate indicates you used 456 kWh from the home wall socket to do so.

Problem: such a recharging consumption is 37% of the total consumption (456/1,233.28). Recharging a Volt shouldn’t be nearly 40% of your total electric bill, especially when you only recharged at home an average of 18.8 miles /day for that 10-week period (6.5 kWh/day). A roommate running a 1,500 watt space heater for five hours a day would use 7.5 kWh/day. Those two items alone would account for ~75% of the day’s consumption.

Perhaps you actually recharged more of the total ev miles away from home (i.e., the fuel economy was better than 34.7 kWh/100 miles), leaving you with fewer ev miles to be recharged at home at a better fuel economy rate.
 
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