A question on home charging cost

[5280mcs]

Howdy,
Just wondering out loud about the charging cost. Currently have 3 EVs at home. One Level 2 charger.
All the cars are programed to charge after 9PM and stops before 6 AM next day.
My question is that would it be cheaper to charge on a household plug which is rated 15 AMP than a level 2 charger that's on 50 AMP breaker.
I believe the cost should be the same as we are talking about the output.
For instance, a bowl of soup from Chipotle that you consumed in 10 seconds should be the same price even if you take 10 minutes to finish it since the charging speed is not the factor in the cost in this situation.

Am I right?

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[Chewy734]

a bowl of soup from Chipotle that you consumed in 10 seconds should be the same price even if you take 10 minutes to finish it

Yes

 

[edman007]

If you have TOU pricing, it depends on how many miles you drive per day. If you were to average 50mi/day at 2.2mi/kWh, and charge on L1 (12A @120V) then you need to charge for ~15h a day, this can't fit in your lowest TOU price which requires charging completes within 9 hours. A 240V, 12A charger however would be fine.

 

[Tim-in-CA]

Howdy,
Just wondering out loud about the charging cost. Currently have 3 EVs at home. One Level 2 charger.
All the cars are programed to charge after 9PM and stops before 6 AM next day.
My question is that would it be cheaper to charge on a household plug which is rated 15 AMP than a level 2 charger that's on 50 AMP breaker.
I believe the cost should be the same as we are talking about the output.
For instance, a bowl of soup from Chipotle that you consumed in 10 seconds should be the same price even if you take 10 minutes to finish it since the charging speed is not the factor in the cost in this situation.

Am I right?

It technically will be more expensive charging on 120V vs 240V as there is slightly better efficiency with 240. This is the amount of power that is lost during conversion from the wall input. But I'd say it shouldn't be enough to impact you much. The bigger issue is amount of range you gain on 120 is much less than 240. 120 you will get 1-2 miles per hour range vs 10-30 miles per hour on 240. This varies by vehicle. I'd say, keep the vehicle you drive most on 240, and keep the other's on 120.

The other issue is that if you have two vehicles charging at 120 from the same breaker in your garage, you will exceed the breaker's rating and probably trip it. If you can find two different 120 circuits in your garage, put one EV on each.

 

[COdogman]

Chipotle sells soup?

 

[5280mcs]

It technically will be more expensive charging on 120V vs 240V as there is slightly better efficiency with 240. This is the amount of power that is lost during conversion from the wall input. But I'd say it shouldn't be enough to impact you much. The bigger issue is amount of range you gain on 120 is much less than 240. 120 you will get 1-2 miles per hour range vs 7-9 miles per hour on 240. This varies by vehicle. I'd say, keep the vehicle you drive most on 240, and keep the other's on 120.

The other issue is that if you have two vehicles charging at 120 from the same breaker in your garage, you will exceed the breaker's rating and probably trip it. If you can find two different 120 circuits in your garage, put one EV on each.

Thanks for the info. Yes, I totally forgot the power loss during the conversation even though the loss could be minimal.
Each of the our 120 circuit that charges the vehicle has it's own breaker. So everything runs fine. I normally don't drive my R1s till weekend so charging at 120 would be acceptable practice.

 

[BigSkies]

I remember some YouTube guy tested a Tesla charging at different L2 amperage’s to see if there was a difference.

Higher amperage was slightly more efficient, but it was in the 1% to 2% range. Nothing I’d be concerned about.

 

[SwampNut]

Howdy,
Just wondering out loud about the charging cost. Currently have 3 EVs at home. One Level 2 charger.
All the cars are programed to charge after 9PM and stops before 6 AM next day.
My question is that would it be cheaper to charge on a household plug which is rated 15 AMP than a level 2 charger that's on 50 AMP breaker.
I believe the cost should be the same as we are talking about the output.
For instance, a bowl of soup from Chipotle that you consumed in 10 seconds should be the same price even if you take 10 minutes to finish it since the charging speed is not the factor in the cost in this situation.

Am I right?

Mostly, probably, maybe. Do you have a demand charge? Do you know when it applies? We have that, so the highest-consumption hour for the month results in a "penalty" charge. So I make sure that we charge when the air conditioning is mostly done for the day.

For actual per-kWh charges it's actually cheaper to fast charge. There's a loss inherent to the process, which effectively goes down if you get it over with quickly.

 

[Treebeard]

Howdy,
Just wondering out loud about the charging cost. Currently have 3 EVs at home. One Level 2 charger.
All the cars are programed to charge after 9PM and stops before 6 AM next day.
My question is that would it be cheaper to charge on a household plug which is rated 15 AMP than a level 2 charger that's on 50 AMP breaker.
I believe the cost should be the same as we are talking about the output.
For instance, a bowl of soup from Chipotle that you consumed in 10 seconds should be the same price even if you take 10 minutes to finish it since the charging speed is not the factor in the cost in this situation.

Am I right?

You are charged by the kWh. The power company doesn’t care how fast or slow you use it.

 

[HaveBlue]

Make the most use of the monthly service charge for your meter. The bigger the meter, the bigger the service charge the power company wants. If you have a 200A panel and never use more than 100 at a time, you are paying every month for the bigger panel.

 

[SwampNut]

You are charged by the kWh. The power company doesn’t care how fast or slow you use it.

You don’t know that. Ours does care.

 

[Treebeard]

You don’t know that. Ours does care.

Your power company cares how fast you use power at your home? So if you have a light on, that electricity cost less than if you are charging you car? Post a pic of you power bill?

Make the most use of the monthly service charge for your meter. The bigger the meter, the bigger the service charge the power company wants. If you have a 200A panel and never use more than 100 at a time, you are paying every month for the bigger panel.

This makes no sense, but different electric companies charge different ways. But you own your panel not
your meter. So you are charged a monthly fee for the meter. Your meter may be based on your panel size, but there is nothing saying your 100 amp panel doesn’t have a 125 amp meter on it. My electric company has a customer daily charge of .55 for each thirty day period. They no longer have a separate meter rental charge. I also have off peak charging for my EV which saves me .04 per kWh. My EV is the only thing in my house that has the off peak use.

 

[emoore]

Your power company cares how fast you use power at your home? So if you have a light on, that electricity cost less than if you are charging you car? Post a pic of you power bill?

This makes no sense, but different electric companies charge different ways. But you own your panel not
your meter. So you are charged a monthly fee for the meter. Your meter may be based on your panel size, but there is nothing saying your 100 amp panel doesn’t have a 125 amp meter on it. My electric company has a customer daily charge of .55 for each thirty day period. They no longer have a separate meter rental charge. I also have off peak charging for my EV which saves me .04 per kWh. My EV is the only thing in my house that has the off peak use.

A bunch of power companies have a demand charge. So the highest rate in a month, typically over an hour, gets charged at a much higher rate.

 

[Treebeard]

A bunch of power companies have a demand charge. So the highest rate in a month, typically over an hour, gets charged at a much higher rate.

Do you mean the highest demand hour becomes the monthly rate. So the more kWh pulled in a time period the more each kWh cost and that sets the price. That’s insane. I’ve lived in four states and have not seen that, but times change.

 

[emoore]

Do you mean the highest demand hour becomes the monthly rate. So the more kWh pulled in a time period the more each kWh cost and that sets the price. That’s insane. I’ve lived in four states and have not seen that, but times change.

No. That one hour is charged at a very high price so it could be significant. I think my father in laws demand rate is nearly $2/kWh. So if you run your AC and charge your truck it could be an extra $30-$40 extra.

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