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Charging Model 3

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tony26

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I live in California and I have PG&E, my cost is $0.28/kWh, is there a way to figure out how much it would cost to charge an electric vehicle on a 110v outlet 10 or 20 percent? I don't travel that far, but I have looked and looked and I can't find how much it would cost to charge say 20 percent. I've found a lot of places that say how much it would cost to charge the car until full. But if I only use 10 or 20 percent a day, is there a formula that I could use to figure out just on a normal 110v?

If this has been answered before I'm sorry, I've been looking for a formula for about a month or so and could not find anything.
 
You didn't say which car you have. You can't figure out percent without knowing the battery size. So, I'll give the example math.

Model 3 Long Range, usable capacity is about 75kWh, so each 10% is 7.5kWh into the battery. Charging efficiency is going to be lower at 120VAC because the overhead of running pumps and computers is a higher percentage of the total power, so let's say 80% of the energy from the wall is going into the battery. The Mobile Connector on a NEMA 5-15 outlet (using the adapter provided with the car) draws 12A at 120VAC.

7.5kWh / 80% = 9.375kWh
9.375kWh * $0.28/kWh = $2.63

9.375kWh / (120V * 12A / 1000) = 6.51 hours to charge 10% of a Model 3 Long Range battery pack.

If you have a different battery pack, adjust the number of kWh to represent 10% of your actual battery.
 
You didn't say which car you have. You can't figure out percent without knowing the battery size. So, I'll give the example math.

Model 3 Long Range, usable capacity is about 75kWh, so each 10% is 7.5kWh into the battery. Charging efficiency is going to be lower at 120VAC because the overhead of running pumps and computers is a higher percentage of the total power, so let's say 80% of the energy from the wall is going into the battery. The Mobile Connector on a NEMA 5-15 outlet (using the adapter provided with the car) draws 12A at 120VAC.

7.5kWh / 80% = 9.375kWh
9.375kWh * $0.28/kWh = $2.63

9.375kWh / (120V * 12A / 1000) = 6.51 hours to charge 10% of a Model 3 Long Range battery pack.

If you have a different battery pack, adjust the number of kWh to represent 10% of your actual battery.
Thank you, I have a Model 3 Long Range 2022. Thank you for the formula, that helps a lot.
 
I did not know this, thank you for letting me know. I should get a 240V installed.
One more thing to note: if you are only installing the 240V circuit for charging efficiency, its unlikely to ever pay for itself. This is dependent on the complexity of the installation, but just getting an electrician/permit for Sacramento is easily $300 or more, so you'll have to do ~$3000 worth of charging at an absolute minimum to make it break even. That's 10714 kwh, or about 40000 miles of driving(!). Not to say it'll NEVER break even, and there are always the arguments that its better for the environment et al (all fine ideas!), it just may not be worth the effort. 10714kwh sounds like its about five years of your driving.
 
Thank you, I have a Model 3 Long Range 2022. Thank you for the formula, that helps a lot.

There is very little chance that your electricity cost is a flat .28/kWh here in CA. Its either a tiered rate (so you need to account for the EV likely pushing you into a higher tier) or its a Time of Use rate, and because you are charging on 120, unless you charge only in the middle of the night, may not be accounting for time when the rates change.
 
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