Home charging 110 vs 240 - Efficiency?

[JeffKeryk]

Question for all the smarty pants people like @OVERKILL ....
1st, is CA 110 or 120 v? 220 or 240 v ?

2nd - the real question - Is the cost of charging cheaper with 240v? Someone said something like you lose perhaps 30% due to efficiency with 110v.

Asking for a friend with one of those stupid Teslas... Thanks!

 

[UncleDave]

Not smart here, but know the answers

Ca is 120/ 240

240 is more efficient - therefore cheaper.

 

[brianl703]

240 is more efficient - therefore cheaper.

Maybe. If the EV has active battery cooling, 240V charging at a higher rate maybe enough to cause the AC compressor to run to cool the battery down, when a slower charge rate at 120V would not cause the battery to heat up to the point that active cooling is needed.

This, of course, depends on the ambient temperature, but I can tell you this:

On my 2013 Volt, parked in the garage in the summer, 240V charging often causes the AC compressor to run.

In the same (or similar) conditions, 120V almost never causes the AC compressor to run.

Since energy used to run the AC compressor is not being used to charge the battery, it is probably more efficient/cheaper to charge at a rate that does not cause the AC compressor to run (this also reduces the heat buildup in the garage, that heat buildup which probably raises the temperature inside the house--insulation isn't perfect, after all....)

And, for those reasons, if we are having one of those good 'ole Virginia heat waves, and I don't need to drive the car again till the next day, I charge it at 120V.

 

[JeffKeryk]

240 is more efficient - therefore cheaper.

That answers my question. So 240 is, good to know.
Is it much different? What is the efficiency loss from?

I don't know squat about electricity...
All I know is, when working on cars, there is smoke in the wires...
As long as you keep the smoke in the wires you are OK.

And the Eagle flies over the Indian and the Rock.

 

[UncleDave]

120V/240V Charging Efficiency - Answers!

TL;DR: Conclusion: Charging a Model 3 at 240V is very efficient, and noticeably more efficient than charging at 120V.

forums.tesla.com

Setup:
Temperature: 75-85F (24-29C) in my garage
Equipment used:
- IoTaWatt in the Circuit breaker box, with dedicated monitors per circuit
- Stats running on my phone, querying the car's API
- Gen 2 Mobile Connector charging at 32A @ 240V, or 12A @ 120V.

Technique:
- Charging started in the evening, stopped in the morning. IoTaWatt and Stats were queried to find how much power was drawn from the house panel, and how much was stored in the battery.
- The 240V outlet and 120V outlet are very short runs from the Circuit Breaker box, minimizing power loss in the wiring. The 240V circuit is about 15' of AWG 6, and the 120V circuit is about about 5' of AWG 12.

Results:
At 240V (Measured average about 252V), Stats showed 40.62 kwh added to the battery. IoTaWatt showed 42.5 kwh pulled from the wall. Efficiency = 40.62/42.5=95.6%.
At 120V (Measured average about 126V), Stats showed 10.15 kwh added to the battery. IoTaWatt showed 11.9 kwh pulled from the wall. Efficiency = 10.15/11.9=85.2%

Conclusion
Charging at 240V is very efficient, and noticeably more efficient than charging at 120V. You will pay about 12% more to charge at 120V compared with charging at 240V.

Example: Driving 10,000 miles per year, at 250 Wh/mile, will take about 2500 kwh from the battery. At 240V, you'll pull (2500/0.956) = 2600 kwh from the wall over the year to recharge the battery. At 120V, you'll pull (2500/.852)=2900 kwh from the wall over the year, which is 12% more power and likely 12% more money.

 

[Zee09]

I run all my machine tools at my house on 240. I even run my desktop on 240v. My electric bill is nothing... The only way to go

 

[Wolf359]

Basically the higher the voltage the lower the line losses from resistance. That's why at the power plant it goes out at 360 thousand volts and eventually gets stepped down to 240. They use 220/240 intermittently, you basically should have about 240, but if you're at the end of a long street the voltage might drop down to 220 and that's still acceptable.

 

[ZeeOSix]

Question for all the smarty pants people like @OVERKILL ....
1st, is CA 110 or 120 v?

It probably measures out more like 115 volts ... but they call it "120". There's probably a range that's acceptable per the power company.

 

[JeffKeryk]

You guys are awesome-sauce!

 

[kschachn]

I run all my machine tools at my house on 240. I even run my desktop on 240v. My electric bill is nothing... The only way to go

The energy consumed - the watts are the same. And that’s what your meter measures.

 

[kschachn]

It probably measures out more like 115 volts ... but they call it "120". There's probably a range that's acceptable per the power company.

Yeah it’s typically 117 or 118 here.

 

[RooflessVW]

Charging efficiency in and of itself hardly matters.

Only 240v charging is getting you a useable range overnight.

 

[earlyre]

 

[OVERKILL]

Basically the higher the voltage the lower the line losses from resistance. That's why at the power plant it goes out at 360 thousand volts and eventually gets stepped down to 240. They use 220/240 intermittently, you basically should have about 240, but if you're at the end of a long street the voltage might drop down to 220 and that's still acceptable.

Oh, it goes out higher than that, lol. Some plants are 500K volts.

@UncleDave did a great job with the explanations, nothing I can add to that.

 

[Zee09]

Isn't CA very high per kwh?

 

[JeffKeryk]

Charging efficiency in and of itself hardly matters.

Only 240v charging is getting you a useable range overnight.

Absolutely; 120v gets my car 3 to 4 MPH. 240v with the NEMA 14-50 recepticle gets 28 to 32 MPH.
The dual motor cars can charge faster...

My question was not about charging speed; it was about the efficiency of delivering the power.
I did not know if there was a cost difference between 120v and 240v.
In my case, my cost is very low because I installed solar a few years back.
Otherwise, electricity costs in CA are among the highest in the nation.

 

[jurko]

I run all my machine tools at my house on 240. I even run my desktop on 240v. My electric bill is nothing... The only way to go

Have you ever done any math before you decide to make unsubstantiated claim as this that your electric bill is nothing because you ran most devices on 240V?
Yes, the 240V uses 50% less amps but the amps is not what you pay for.
Let me give you example:
Let's say you have a tool with 240V 1HP motor.
That motor will pull about 4.2 amps. This motor will use:240x4.2=1,008 watts
The same 1HP motor but 120V will pull 8.4 amps and will use:120x8.4=1,008 watts.
So how can you claim you pay almost nothing for electricity and this is the only way to go because you run mostly 240V devices is beyond me.

 

[Zee09]

Have you ever done any math before you decide to make unsubstantiated claim as this that your electric bill is nothing because you ran most devices on 240V?
Yes, the 240V uses 50% less amps but the amps is not what you pay for.
Let me give you example:
Let's say you have a tool with 240V 1HP motor.
That motor will pull about 4.2 amps. This motor will use:240x4.2=1,008 watts
The same 1HP motor but 120V will pull 8.4 amps and will use:120x8.4=1,008 watts.
So how can you claim you pay almost nothing for electricity and this is the only way to go because you run mostly 240V devices is beyond me.

Just about the cheapest electricity in the nation followed by less line loss and Baldor Super E Motors throughout as well as the EmPower Maryland energy rewards program in conjunction with their Off Peak energy discount.
My house and shop electric bill averages $45 a month total which includes 3 separate garages as well.

 

[bbhero]

That answers my question. So 240 is, good to know.
Is it much different? What is the efficiency loss from?

I don't know squat about electricity...
All I know is, when working on cars, there is smoke in the wires...
As long as you keep the smoke in the wires you are OK.

And the Eagle flies over the Indian and the Rock.

Your need to learn about electrical power and batteries... Battery University sponsored by Cadex is a great place to learn about the batteries...


Read in that site about batteries.... And charging them..... EV charging, etc etc.... Learn about how certain very large batteries cannot be charged 0°C or colder.... There's a treasure trove of information on all of that from Battery University website.

What you read on there... Will let you know some extremely interesting information.

All I will say is that there's a whole, whole, whole lot more to learn there than what 99.9 percent of people realize at this time.

To be fair... Hydrocarbon technology suffered greatly in it's beginning too. Cold temperature performance killed many motors early on or greatly cut their usable life span GREATLY. Synthetic oil technology started with the jet age. For regular vehicle use that didn't happen until almost 30 years later. Additives and further refinement in hydrocarbons led to better and better oils that assisted in making vehicles last far far longer. We are where we are today because of tremendous knowledge growth and technological development.

Large Batteries like EVs are in reality still in it's early stages. Even though lithium ion batteries were around since the 70s. There is a very, very, very large learning mountain to climb with large batteries.

 

[jurko]

Just about the cheapest electricity in the nation followed by less line loss and Baldor Super E Motors throughout as well as the EmPower Maryland energy rewards program in conjunction with their Off Peak energy discount.
My house and shop electric bill averages $45 a month total which includes 3 separate garages as well.

Now you sound more believable. Looks like you pulled the rabbit out of correct hat.