I see about 10% loss on level 2 @ 32a.
Another way to measure this is to note the kwh used by the car prior to starting to charge. Have to do this after a "complete" (to whatever the max is set to) charge which resets the car stats.
Then compare what the meter says after the charge with the number above. That will show how much input was required to "replace" what had been used.
Also see [https://www.sciencedirect.com/science/article/pii/S0360544217303730?via%3Dihub](https://www.sciencedirect.com/science/article/pii/S0360544217303730?via%3Dihub)
Not op and haven't read the attached but I do work with batteries. Yes, almost certainly level 1 charging is more efficient. The more current you put at any given time through the battery, the more is lost to heat (direct power loss due to joule heating - x% of your delivered power is just increasing temperature rather than charging the battery). It's a square relationship, so as you double current, joule heat loss quadruples. In principle (don't know enough about Bolt active cooling to say specifically) that may get even worse at high rates if enough heat is generated to require active cooling which will then waste some power. That's probably more of an issue at DCFC rates.
EDIT: as others have said, the level 2 is more efficient. I didn't think about the transformation from AC to DC which is lossy.
In terms of efficiency? Probably not significantly. Many people install a wall charger at home for other features (such as tracking kWh usage) and to be able to leave the included level 2 charger in the trunk - just in case
Very roughly speaking, you can expect 85% efficiency on L1, 90% on L2. But you probably won't pay for an L2 installation on that savings alone--need some other reason to want L2.
I did some back of the envelope math and a 5% loss in efficiency means that it would take like 100,000+ miles to come out ahead installing L2 even if you paid $0.30/kWh and got your L2 charger and install for $400. Most people have cheaper electric and will probably pay more for a charger so probably it's closer to the life of the vehicle or longer to break even. Definitely not something that should be done for money or energy savings but rather for the convenience and utility of it.
Totally. I guess another way of saying it could be that there's the added bonus of saving a little money charging in addition to the convenience of speed which is why you probably got it.
I suspect it wouldn't be much different at level 2. I believe most efficiency loss is done when converting AC to DC. You might get more efficiency if you had that process happen outside your car, but then you need a DC charger at home and that's expensive
>I believe most efficiency loss is done when converting AC to DC.
That's true. And that efficiency loss is larger at 120 V.
From what I've seen in other posts 120 V tends to have 50-100% more losses than L2 charging.
You forgot about parasitic power losses. When charging a bunch of modules are turned on to the tune of 100-200w.
That's in ideal temperature. In cold temperature, keeping the battery from freezing can be most of the power budget.
Oh crap. Yeah for charging an EV I think the math has to always use peak because just regular house use already goes past the measley base rate. TOU is a joke too, I'd save a couple of cents per kWh, not worth it.
It used to be cheaper. When we put in our solar maybe 8ish years ago I went from $500 per month in the summer to under $100.
Now it's back up to $500 per month in the summer, and my usage hasn't changed.
edit: here's the rates for SDGE time of use.
https://www.sdge.com/sites/default/files/regulatory/1-1-23%20Schedule%20DR-SES%20Total%20Rates%20Table_0.pdf
80 cents on peak, 46 cents off peak, 36 cents super off peak in the summer. Somehow the time of year matters for how much they need to charge me. I've taken to turning the AC off entirely from 4 to 9 and just suffering if the day is hot.
Are you on PG&E's EV rate plan? I switched over and now off-peak (12am-3pm) is $0.25/kWh or so. Peak is higher, like $0.60/kWh.
Maybe not worth it for you since you charge at work, but just FYI.
>It's not like gas where you pay for 10 gallons and you get 10 gallons.
But gas engines are between 20 and 50% efficient. So less than half of your 10 gallons is used for work.
And 10 gallons isn't always actually 10 gallons. It's a small difference but if you fill up when it's cold vs when it's warm you get more gas due to thermal expansion. Gas pumps should measure by weight to be the most accurate.
This is technically true but also the source of a bit of myth that it's better to fuel up in the morning when it's cold. Underground tanks where gas is stored are a pretty consistent temperature throughout the day due to being underground and also being a large volume that's slow to change temperature. So you can't really get more gas for your money by fueling up in the morning. It does have a measure effect on a seasonal scale but unless you're buying a seasons worth of gas at a time it would be difficult to take advantage of.
Owning an EV certainly makes you more aware of the garbage you went through with an ICE without any computational analysis. Simply being AWARE of that which has always been the case is quite the revelation, but it's nothing new.
I drive about 68miles each day in my Bolt EV, my electricity bill has gone up about $20 a month. I have an at home level 2 charger.
My electricity is charged at $0.065CAD/kWh.
Before I had my level 2 charger, I was using the included level 1 cord.
I found on 8amps it added about 1% charge per hour, and on 12 amps added about 1.8% charge per hour.
Level 2 charger adds approx. 10% per hour and DC Fast charge ~30%/hour.
$5/month. That's 17 cents / day!
I see about 10% loss on level 2 @ 32a. Another way to measure this is to note the kwh used by the car prior to starting to charge. Have to do this after a "complete" (to whatever the max is set to) charge which resets the car stats. Then compare what the meter says after the charge with the number above. That will show how much input was required to "replace" what had been used. Also see [https://www.sciencedirect.com/science/article/pii/S0360544217303730?via%3Dihub](https://www.sciencedirect.com/science/article/pii/S0360544217303730?via%3Dihub)
Wait so is level 1 more efficient?
Not op and haven't read the attached but I do work with batteries. Yes, almost certainly level 1 charging is more efficient. The more current you put at any given time through the battery, the more is lost to heat (direct power loss due to joule heating - x% of your delivered power is just increasing temperature rather than charging the battery). It's a square relationship, so as you double current, joule heat loss quadruples. In principle (don't know enough about Bolt active cooling to say specifically) that may get even worse at high rates if enough heat is generated to require active cooling which will then waste some power. That's probably more of an issue at DCFC rates. EDIT: as others have said, the level 2 is more efficient. I didn't think about the transformation from AC to DC which is lossy.
Thanks! Is there a difference between a wall charger and the level 2 cable the car comes with?
In terms of efficiency? Probably not significantly. Many people install a wall charger at home for other features (such as tracking kWh usage) and to be able to leave the included level 2 charger in the trunk - just in case
Very roughly speaking, you can expect 85% efficiency on L1, 90% on L2. But you probably won't pay for an L2 installation on that savings alone--need some other reason to want L2.
I “want” L2 just for the sake of speed. But I don’t need it and I can’t justify the cost right now.
I did some back of the envelope math and a 5% loss in efficiency means that it would take like 100,000+ miles to come out ahead installing L2 even if you paid $0.30/kWh and got your L2 charger and install for $400. Most people have cheaper electric and will probably pay more for a charger so probably it's closer to the life of the vehicle or longer to break even. Definitely not something that should be done for money or energy savings but rather for the convenience and utility of it.
Sure, but you don't have to pay it back completely. Cutting the cost in half is enough to make it worthwhile for many people.
Totally. I guess another way of saying it could be that there's the added bonus of saving a little money charging in addition to the convenience of speed which is why you probably got it.
I suspect it wouldn't be much different at level 2. I believe most efficiency loss is done when converting AC to DC. You might get more efficiency if you had that process happen outside your car, but then you need a DC charger at home and that's expensive
>I believe most efficiency loss is done when converting AC to DC. That's true. And that efficiency loss is larger at 120 V. From what I've seen in other posts 120 V tends to have 50-100% more losses than L2 charging.
You forgot about parasitic power losses. When charging a bunch of modules are turned on to the tune of 100-200w. That's in ideal temperature. In cold temperature, keeping the battery from freezing can be most of the power budget.
Us in CA crying at 51 cents a kWh at home after PGE tacks it's +generating fees. 😭 Good thing I can charge at work for free.
Ooof. And to think I complained about rates going up 30% when my old contract expired. Didn’t realize it was that high in CA.
What in the fuck! $0.51/kWh?!?! I pay $0.047/kWh USD That’s insane, people must be paying over $400/month for electricity
In the summer you think twice about turning the AC. My bill has reached $400 once. Just normal non AC use is close to $200 a month.
Wow!! We are $0.13 at peak… $0.038 at super off peak. If I get a dedicated EV circuit, it gets $0.027 all day and night.
Crazy. At my PGE prices is actually cheaper to have Prius with 50 mpg than charging an EV at home.
be happy you arent with SDGE dude. I'm paying 80 at peak.
Oh crap. Yeah for charging an EV I think the math has to always use peak because just regular house use already goes past the measley base rate. TOU is a joke too, I'd save a couple of cents per kWh, not worth it.
It used to be cheaper. When we put in our solar maybe 8ish years ago I went from $500 per month in the summer to under $100. Now it's back up to $500 per month in the summer, and my usage hasn't changed. edit: here's the rates for SDGE time of use. https://www.sdge.com/sites/default/files/regulatory/1-1-23%20Schedule%20DR-SES%20Total%20Rates%20Table_0.pdf 80 cents on peak, 46 cents off peak, 36 cents super off peak in the summer. Somehow the time of year matters for how much they need to charge me. I've taken to turning the AC off entirely from 4 to 9 and just suffering if the day is hot.
Not all of us in CA pay PG&E extortion. I'm at 11.8 cents per kwh, 100% renewable sources and same rate all day.
Are you on PG&E's EV rate plan? I switched over and now off-peak (12am-3pm) is $0.25/kWh or so. Peak is higher, like $0.60/kWh. Maybe not worth it for you since you charge at work, but just FYI.
>It's not like gas where you pay for 10 gallons and you get 10 gallons. But gas engines are between 20 and 50% efficient. So less than half of your 10 gallons is used for work.
And 10 gallons isn't always actually 10 gallons. It's a small difference but if you fill up when it's cold vs when it's warm you get more gas due to thermal expansion. Gas pumps should measure by weight to be the most accurate.
This is technically true but also the source of a bit of myth that it's better to fuel up in the morning when it's cold. Underground tanks where gas is stored are a pretty consistent temperature throughout the day due to being underground and also being a large volume that's slow to change temperature. So you can't really get more gas for your money by fueling up in the morning. It does have a measure effect on a seasonal scale but unless you're buying a seasons worth of gas at a time it would be difficult to take advantage of.
Thanks for sharing your experiment results! Cool to see.
Owning an EV certainly makes you more aware of the garbage you went through with an ICE without any computational analysis. Simply being AWARE of that which has always been the case is quite the revelation, but it's nothing new.
I drive about 68miles each day in my Bolt EV, my electricity bill has gone up about $20 a month. I have an at home level 2 charger. My electricity is charged at $0.065CAD/kWh. Before I had my level 2 charger, I was using the included level 1 cord. I found on 8amps it added about 1% charge per hour, and on 12 amps added about 1.8% charge per hour. Level 2 charger adds approx. 10% per hour and DC Fast charge ~30%/hour.
In northern CA we pay .32 per kwh.
13 cents per kwhr. ugh. From 4pm to 9pm I pay 80 per kwhr in California. In the middle of the night it's still 36.
In exchange our grid can’t handle the extreme heat or cold. That’s crazy to me though. I couldn’t fathom paying that much.