How much energy does a 120 wall plug draw when charging?

SOLIDAge

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I know that my car’s battery is 88kWh. So in theory it would take 88kWh to go from 0-100.

So my question is that I know that when plugged into a 120 wall it draws power and converts it on the car to 240 then delivers energy. my understanding is that draw isn’t taxing and is like a modern appliance.

Whar I’m getting at is that my buddy and I were in a long conversation about electric cars and him not believing the actual power draw that they have, and that they aren’t cost saving… his data is that when I was visiting for a week and had my car plugged in, he was billed 500kWh more than his average a month. According to my car logs it charged roughly 200 miles. I have an AWD extended drive so rounding up my max, that mean that I only drew 88kWh in my calculations and woulda had to charge 0-100 almost 6 times to hit that 500kWh UNLESS that 120 draw is super not efficient and not 1:1 to what is delivered to the car and then inverted.

so am I crazy? Is he? Am I figuring that out wrong? Any links and data sources that him and I can read to put this to rest would be super helpful.
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woody

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The MMe has a 10.5kW charger. To compare, the Bolt has a smaller charger, the Volt even smaller. At 120 level 1 the rate will be slower than your EVSE level 2 and be dependent on your EVSE capacity.
The MMe will charge a bit faster than the EVs with smaller chargers at either level.
The amount of electrons to full charge is the same, the time it takes is the difference.
Level 1 charging will consume more energy/hour(1 -2kW) than your average appliance. Our heat pump consumes more electrons than our EVs.
Granted, faster charging in warmer weather would produce a bit more energy loss to heat, but nowhere near the amounts indicated by your buddy's figures. (reminder: heat and cold affect electron flow)
Current (primitive) technology leans towards slower (120) charging for longer battery life.
We have a net zero home (no fossil fuels for energy; we produce [solar] more energy than we use) and only have two EVs. We rotate them, charging directly from our solar production. Level 1 usage is within the range described above.
Standard residential utility rates are cost saving for EVs.
There must be something else involved, if your buddy's readings are accurate.
 

phidauex

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His math is off somewhere. If you only drove 200 miles there is no way you charged 500 kWhs at his place. More likely you were visiting so they had more lights running, more heat, more cooking, etc., which would have happened no matter the visitor. Assuming you charged a full 88 kWhs (quite conservative for 200 miles), that would cost between $8 and $24, depending on where you live. I do buy my in laws a six pack or two when I charge a bit at their place as a nice gesture, even though that is rarely even the cost of my charge.
 

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I know that my car’s battery is 88kWh. So in theory it would take 88kWh to go from 0-100.

So my question is that I know that when plugged into a 120 wall it draws power and converts it on the car to 240 then delivers energy. my understanding is that draw isn’t taxing and is like a modern appliance.

Whar I’m getting at is that my buddy and I were in a long conversation about electric cars and him not believing the actual power draw that they have, and that they aren’t cost saving… his data is that when I was visiting for a week and had my car plugged in, he was billed 500kWh more than his average a month. According to my car logs it charged roughly 200 miles. I have an AWD extended drive so rounding up my max, that mean that I only drew 88kWh in my calculations and woulda had to charge 0-100 almost 6 times to hit that 500kWh UNLESS that 120 draw is super not efficient and not 1:1 to what is delivered to the car and then inverted.

so am I crazy? Is he? Am I figuring that out wrong? Any links and data sources that him and I can read to put this to rest would be super helpful.
A 120 volt 15 ampere outlet provides 12 amperes for charging because of the 80% rule. 120 volts times 12 amperes is 1440 watts or 1.44 kW. 500 kWh divided by 1.44 kW is 347.22 hours which is 14.47 days or more than double the time that you were there.

Your car is not responsible for the extra 500 kWh.

120 volts is not converted to 240 volts. It is rectified to DC and multiplied up to over 300 volts DC to charge the battery. 120 volts AC charging is less efficient than 240 volts AC charging which is less efficient than direct DC charging.
 


Mach1E

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I know that my car’s battery is 88kWh. So in theory it would take 88kWh to go from 0-100.

So my question is that I know that when plugged into a 120 wall it draws power and converts it on the car to 240 then delivers energy. my understanding is that draw isn’t taxing and is like a modern appliance.

Whar I’m getting at is that my buddy and I were in a long conversation about electric cars and him not believing the actual power draw that they have, and that they aren’t cost saving… his data is that when I was visiting for a week and had my car plugged in, he was billed 500kWh more than his average a month. According to my car logs it charged roughly 200 miles. I have an AWD extended drive so rounding up my max, that mean that I only drew 88kWh in my calculations and woulda had to charge 0-100 almost 6 times to hit that 500kWh UNLESS that 120 draw is super not efficient and not 1:1 to what is delivered to the car and then inverted.

so am I crazy? Is he? Am I figuring that out wrong? Any links and data sources that him and I can read to put this to rest would be super helpful.
Sounds like the fact that he had people visiting for a week might have raised the electric bill?

Or he got his electric bill, had sticker shock and this is his way of asking you for gas/electron money?

If he had his own gas pump at his house would he be ok with you filling up your car a few times? (Not sure how generous your friend is).
 

DR.J56

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A 120 volt 15 ampere outlet provides 12 amperes for charging because of the 80% rule. 120 volts times 12 amperes is 1440 watts or 1.44 kW. 500 kWh divided by 1.44 kW is 347.22 hours which is 14.47 days or more than double the time that you were there.

Your car is not responsible for the extra 500 kWh.

120 volts is not converted to 240 volts. It is rectified to DC and multiplied up to over 300 volts DC to charge the battery. 120 volts AC charging is less efficient than 240 volts AC charging which is less efficient than direct DC charging.
THIS! Simply plugging in the numbers to Ohms law will net the numbers you need to convince your friend. Find what he pays per kWh and buy him a beer or two.
 

mkhuffman

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A 120 volt 15 ampere outlet provides 12 amperes for charging because of the 80% rule. 120 volts times 12 amperes is 1440 watts or 1.44 kW. 500 kWh divided by 1.44 kW is 347.22 hours which is 14.47 days or more than double the time that you were there.

Your car is not responsible for the extra 500 kWh.

120 volts is not converted to 240 volts. It is rectified to DC and multiplied up to over 300 volts DC to charge the battery. 120 volts AC charging is less efficient than 240 volts AC charging which is less efficient than direct DC charging.
This ^^^^ 100%. There is no way your car added 500 kWh to his bill.
 

RickMachE

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We visited our son back in September, and charged with 110. Our impact on his monthly bill was about $10.

@SOLIDAge, your battery is actually 98kWh. You can use 88kWh of it, although with an update that your vehicle should get from the dealer that's been raised to 91kWh. Normally, you should charge to 90%, only going to 100% the night before your trip. This is explained in your manual.

Also, if you put 88kWh into your car, you'd actually be taking closer to 100 from the wall, and losing about 12% along the way.
 
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SOLIDAge

SOLIDAge

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A 120 volt 15 ampere outlet provides 12 amperes for charging because of the 80% rule. 120 volts times 12 amperes is 1440 watts or 1.44 kW. 500 kWh divided by 1.44 kW is 347.22 hours which is 14.47 days or more than double the time that you were there.

Your car is not responsible for the extra 500 kWh.

120 volts is not converted to 240 volts. It is rectified to DC and multiplied up to over 300 volts DC to charge the battery. 120 volts AC charging is less efficient than 240 volts AC charging which is less efficient than direct DC charging.
what is the 80% rule? Would it being quite cold outside where it was charging reduced Thad %?
 

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80% rule is that all EV's now - and circuits pulling for 3 hours or more - must pull only 80% or less of the rated current for the wires/breaker.
 

mkhuffman

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what is the 80% rule? Would it being quite cold outside where it was charging reduced Thad %?
80% rule is that all EV's now - and circuits pulling for 3 hours or more - must pull only 80% or less of the rated current for the wires/breaker.
The NEC (National Electrical Code) provides safety standards for installing and wiring homes for electricity. The NEC specifies that outlets and wires need to be able to handle 120% of a continuous load expected for the system. So a 15 amp outlet is rated to handle up to 15 amps, but not continuously (like with an EV charger or another device that pulls a steady current).

For example, the normal continuous load allowed by the NEC on a 50 amp outlet is 42 amps, which is 80% of 50 amps. For a 15 amp outlet, the maximum continuous load should not exceed 80% of the outlet or wire rating - which is 12 amps. 15 amps is 120% of 12 amps. (Math.) You can exceed 12 amps if you want, but the 15 amp circuit breaker will probably trip after a period of time.

That is why the Ford charger does not try to pull 15 amps. If it did, the circuit breaker would trip and you would not be able to charge your car.

It is a safety thing to prevent wires and outlets from overheating and catching on fire.
 

Peugfan

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The NEC (National Electrical Code) provides safety standards for installing and wiring homes for electricity. The NEC specifies that outlets and wires need to be able to handle 120% of a continuous load expected for the system.

For example, the normal continuous load allowed by the NEC on a 50 amp outlet is 42 amps, which is 80% of 50 amps. For a 15 amp outlet, the maximum continuous load should not exceed 80% of the outlet or wire rating - which is 12 amps. 15 amps is 120% of 12 amps. (Math.)
125% NOT 120%. You need a math refresher course. 15/12 = 1.25 (125%). 100/80 = 1.25 (125%).
 

mkhuffman

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125% NOT 120%. You need a math refresher course. 15/12 = 1.25 (125%). 100/80 = 1.25 (125%).
I remembered the NEC code incorrectly. You are right. “where a branch circuit supplies continuous loads or any combination of continuous and noncontinuous loads, the minimum branch-circuit conductor size, before the application of any adjustment or correction factors, shall have an allowable ampacity not less than the noncontinuous load plus 125 percent of the continuous load.” This is NEC 215.2.
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