I share ownership of a small office building and my other co-owners are cheapskates. I have an oppty to build a 120 or 240 v plug into a light pole to occasionally charge during the workday. I need to figure out the dollar cost of say 8hrs a week, on a 120 and a 240 (using only 208) to make my case. Does anyone know how much power a 2015 S80 draws on those 2 configurations?
-
Want to remove ads? Register an account and login to see fewer ads, and become a Supporting Member to remove almost all ads.
Looking for what the cost of using a regular 120v outlet is?
- Thread starter joose
- Start date
ucmndd
Well-Known Member
Assuming 20 amp circuit:
120v x 16A (max draw on 20A circuit) = 1.9kw
Assuming 15 amp circuit:
120v x 12A (max draw on a 15A circuit) = 1.4kw
Assuming 30 amp 208v:
208v x 24A (max draw on 30A circuit) = 5kw
Figure out any other combination of
Voltage/amperage with the equation:
Voltage x ((0.8) x circuit amperage) = power in watts
Multiply the kw figure by the number of hours you anticipate charging per week, then multiply that by the estimated price per kWh your business pays for electricity.
120v x 16A (max draw on 20A circuit) = 1.9kw
Assuming 15 amp circuit:
120v x 12A (max draw on a 15A circuit) = 1.4kw
Assuming 30 amp 208v:
208v x 24A (max draw on 30A circuit) = 5kw
Figure out any other combination of
Voltage/amperage with the equation:
Voltage x ((0.8) x circuit amperage) = power in watts
Multiply the kw figure by the number of hours you anticipate charging per week, then multiply that by the estimated price per kWh your business pays for electricity.
murphyS90D
Member
Install a meter and measure it.
120 Volt Pass-Through kWh Meter, 2-Wire (1 hot, 1 neutral), 50A, 60Hz, | EKM Metering Inc.
That is the 120 volt version. There is also a 240 volt version. They measure to two decimal places.
120 Volt Pass-Through kWh Meter, 2-Wire (1 hot, 1 neutral), 50A, 60Hz, | EKM Metering Inc.
That is the 120 volt version. There is also a 240 volt version. They measure to two decimal places.
Just as a really rough estimate:
Let’s say you install a 5kW charger and use it 8 hours a week. That’s 40kWh a week. Or 160 kWh a month.
Obviously you should look at a power bill and see how much you’re utility is charging per kWh. Let’s just say it’s $0.15 / kWh.
Using the above numbers that equates to $24 a month. Hope it won’t break the “cheapskate” partners bank.
Let’s say you install a 5kW charger and use it 8 hours a week. That’s 40kWh a week. Or 160 kWh a month.
Obviously you should look at a power bill and see how much you’re utility is charging per kWh. Let’s just say it’s $0.15 / kWh.
Using the above numbers that equates to $24 a month. Hope it won’t break the “cheapskate” partners bank.
P100DHG.
Member
Here is what you need to know.
1 amp = 120 watts
1000 watts = 1kw
Scenario 1:
20 amp breaker at 120 volts will charge your car at 12amps that’s just how Tesla has it setup for 120 volt. 12 x 120 = 1440 watts or 1.4kw. Multiply 1.4kw x cents per KW (look on your power bill) x 8 hours. Let’s say your 25 cents per kw. That’s 35 cents per hour or $2.80 per day
Scenario 2:
50 amp 220 volt (208 it’s all the same really) utilizes 40amps at the charger so if you have the old mobile connector. But here is the thing 220 volt uses 2 110 legs so your not pulling 40amps your pulling 80 amps just 40 amps on one leg and 40 amps on the other so... your charging at 9.6 kw per hour or $2.80 per hour using 25 cents per hour. Assuming 6 hours cause I doubt you’ll need to charge for 8 hours. $16.80 for 6 hours or just about $20 for 8. But really doubt charge for 8 hours unless you burned through your whole battery getting to work. In fact I doubt you’ll charge 6 hours.
Your charge is a function or your depletion so it’s hard to say how much it will cost not knowing your battery % used to get to work or your power rates.
Better to ask for forgiveness than for permission. Also coming from a very strong real estate background if you’re 50% owner they would be hard press to block you.
1 amp = 120 watts
1000 watts = 1kw
Scenario 1:
20 amp breaker at 120 volts will charge your car at 12amps that’s just how Tesla has it setup for 120 volt. 12 x 120 = 1440 watts or 1.4kw. Multiply 1.4kw x cents per KW (look on your power bill) x 8 hours. Let’s say your 25 cents per kw. That’s 35 cents per hour or $2.80 per day
Scenario 2:
50 amp 220 volt (208 it’s all the same really) utilizes 40amps at the charger so if you have the old mobile connector. But here is the thing 220 volt uses 2 110 legs so your not pulling 40amps your pulling 80 amps just 40 amps on one leg and 40 amps on the other so... your charging at 9.6 kw per hour or $2.80 per hour using 25 cents per hour. Assuming 6 hours cause I doubt you’ll need to charge for 8 hours. $16.80 for 6 hours or just about $20 for 8. But really doubt charge for 8 hours unless you burned through your whole battery getting to work. In fact I doubt you’ll charge 6 hours.
Your charge is a function or your depletion so it’s hard to say how much it will cost not knowing your battery % used to get to work or your power rates.
Better to ask for forgiveness than for permission. Also coming from a very strong real estate background if you’re 50% owner they would be hard press to block you.
dark cloud
Active Member
Yes, in the grand scheme of things it's peanuts. If they are going to be like that I would check to see if one of them uses the fridge/microwave/turns on the lights more often than others, or it someone drinks more coffee than the others, or if someone flushes the toilet more often, then they should be paying more for water usage. It could get pretty stupid if you wanted it to be.
Sounds like a divorce waiting to happen.
ucmndd
Well-Known Member
Only at 120 volts.
No. A NEMA 5-20 adapter will pull 16 amps on a 20 amp circuit.
No. Electricity doesn’t work that way.
Last edited:
For those who don't actually have an electric car yet, this is the most realistic use case at 240 volts.
No matter how long you're plugged in, you'll probably only be charging for an hour or two daily. Unless you drive hundreds of miles to get to work, your battery won't be empty.
Bear in mind that higher amperage charges faster, but costs the same. Say you drove 30 miles to work and used 1 gallon of gas. Filling your tank will cost the same no matter how you pump the gas. Electric cars are no different. Instead of using a gallon of gas, you used 10 kWh of electricity. Filling your battery will cost whatever your power company charges for 10 kWh regardless of how you're plugged in or how fast you charge.
As others have said in a more roundabout way, you're asking the wrong question and providing the wrong information. The car will pull the same amount of power through all configurations. What changes is how long it takes to do it Everyone will highly recommend the 240v configuration (because it's by far the better choice) but if you're only driving 5 or 10 miles to work, feel free use a 110 outlet. Just plug in when you get to work and you'll be fully charged by the end of the day. Anything more than 20 miles and you should definitely consider 240v because you won't be fully charged after 8 hours.
Anyway, we need to know how far you drive if we're going to help you figure this out. As a rough guess, take car's range and divide it by the battery size. Next, divide the number of miles you drive to work by that number. That gives you how many kWh you'll use during your daily drive in a perfect world. I'd adjust it (upward in most cases) by 10 to 20% to account for real world driving. Once you have that, round it up to the nearest whole number and multiply it by the cost of electricity where you are. That's how much you should expect the charging to cost per day.
Since you already have a Tesla, you can skip the guesstimate and just pull how many kWh you used from the trip odometer.
docbrown
Member
My understanding is that charging at 120v is less efficient than 240v. I've seen this discussed in many threads, here's an example: Is 120V charging really less efficient?
whitex
Well-Known Member
The efficiency of charging does not affect the cost of electricity from the source (which is the subject of this thread). If you charger 2hrs a day, you pay for 2hrs a day worth of electricity, no matter how much of it end up in your battery.
I used to charge at 120v 15 amp and 240v 30amp all the time. If you do the math the difference between them should be a factor of 4 (double current, double the voltage). I used to get approximately 3.5 mph on 120v and 18 mph on 240v. So yes there is definitely some inefficiency charging at 120v...about a 22% loss.
Just 8hrs a week?! Are you sure that’s all you would need? That’s like 30 miles of range total at 120, or even less! I bet you will use way more than that!
Anyway, if I were you I would install a separate meter and would certainly go for 30 Amp or more.
Don85D
Member
If this is a business location where customers/clients arrive, consider it a business advantage to have an EV charging station available for their use. There are third party suppliers of fee based charging stations and you would then pay your share when connected. When not connected it's a valid business expense to service customers.
Just another approach that removes the conflict and provides a Level 2 charging station.
Just another approach that removes the conflict and provides a Level 2 charging station.
NeverFollow
Active Member
You could use a standard 120 V plug, but if you can
I would recommend to install a 240 separate line from the main panel
and include a watt meter to it so you can estimate the consumption you will have.
So every month, you can read the 'energy' used and calculate the expense you have.
I use the following device at home, and I have a night plan EV discount from PG&E
$20 - Digital Current Voltage Power Energy Analyzer
Bayite - AC 80-260V 100A BYT-VAEM-034
Similar threads
