Time of use vs Storage option sharing program

[seniorcitizen]

For folks who own Tesla Model Y or other Tesla's how important is to have the ability to charge a car at home 24/7.
We are in MN.
Our driving needs are moderate and we have 3 cars.

Our local power company gives us the option of Time of use program where we pay higher rate during day time and lower rate at night time.

Storage option charge progream only allows charging between 11 pm and 7 am.
Power cost are same for both programs between 11 pm and 7 am.

Storage option program does not require an outside meter install as the charger has a meter built in.
Time of use program requires getting a meter installed installed outside the some.
I have reached out to a few electrician to understand the cost of meter and installation.

Would you pay $500-1000 more to be able to charge at all times?

 

[frankvb]

For the storage option program - what's stopping you from just plugging in the mobile charger cable e.g. in a dryer outlet during the day and charge?

 

[jcanoe]

For folks who own Tesla Model Y or other Tesla's how important is to have the ability to charge a car at home 24/7.
We are in MN.
Our driving needs are moderate and we have 3 cars.

Our local power company gives us the option of Time of use program where we pay higher rate during day time and lower rate at night time.

Storage option charge progream only allows charging between 11 pm and 7 am.
Power cost are same for both programs between 11 pm and 7 am.

Storage option program does not require an outside meter install as the charger has a meter built in.
Time of use program requires getting a meter installed installed outside the some.
I have reached out to a few electrician to understand the cost of meter and installation.

Would you pay $500-1000 more to be able to charge at all times?

First, a few questions.

How many of your 3 vehicles plug in?
How many miles per day, on average, do you drive the Tesla and any of the other vehicles that plug in?
What are the specifications, i.e. how many kilowatts or how many amps at 240V will the charger with the meter built-in support?

In MN, in winter, you are going to want to leave the Tesla plugged in when it is parked at home. You can set up delayed charging so charging will not start before 11PM and/or be done charging by 7AM but the Tesla's battery management system will maintain the battery pack temperature from getting too cold. This will cycle the battery heating on and off throughout the day, use some power (perhaps $0.25 to $0.75 per day in cold weather.)

 

[djmodifyd]

I'm also in minnesota. I went with a time of of use EV program from my power company. I paid the extra to get the extra meter installed for a few reasons: on my bill it is detailed out exactly what power is going to my vehicle. I also only pay roughly .05 per KwH at night.

It is expensive during the day, but I only charge at night so it doesn't matter. I'm not sure what the storage option is? Is that a special charger you buy from the power company? I'd just go with the TOU program and charge at night and save 1000 dollars. With a Y you have more than enough range to only charge at night.

 

[user212_nr]

For folks who own Tesla Model Y or other Tesla's how important is to have the ability to charge a car at home 24/7.

It is not important. Before the pandemic people were at work during the day and did not charge then. It might be important if you only drove your car at night, all night...

Would you pay $500-1000 more to be able to charge at all times?

Having a charger that only works on off-peak times is the more valuable option. No worrying about paying peak rates.

 

[seniorcitizen]

Model Y will be our first electric car.
I am a consultant so driving depends on the location of the client.
Most I have ever driven is 50 miles per day. Typically it is 30-35 miles per day.
I am hoping to get 1 60 AMP circuit installed. My main electrical panel only has 2 slots open.
I am hoping an electrician will be able to get me 60 AMPs but the worst case may be 40 AMPs.

Off peak option will be easy to do but it means that there is no charging available during day time.
How does the car keep the battery pack warm during day time? Does it require to be plugged in? This is my main question.
Going with off peak option will mean that my charger will be offline so I can only plug in the car to a regular 15 amp outlet.
If a 15 amp circuit is good enough to keep the battery pack warm during day time I will be able to get by with off peak option.

Here are the options available to me from my electricity provider
Electric Vehicles | Wright-Hennepin

 

[jcanoe]

Model Y will be our first electric car.
I am a consultant so driving depends on the location of the client.
Most I have ever driven is 50 miles per day. Typically it is 30-35 miles per day.
I am hoping to get 1 60 AMP circuit installed. My main electrical panel only has 2 slots open.
I am hoping an electrician will be able to get me 60 AMPs but the worst case may be 40 AMPs.

Off peak option will be easy to do but it means that there is no charging available during day time.
How does the car keep the battery pack warm during day time? Does it require to be plugged in? This is my main question.
Going with off peak option will mean that my charger will be offline so I can only plug in the car to a regular 15 amp outlet.
If a 15 amp circuit is good enough to keep the battery pack warm during day time I will be able to get by with off peak option.

Here are the options available to me from my electricity provider
Electric Vehicles | Wright-Hennepin

The 60 amp circuit is only a potential benefit for you if you plan to install the Tesla Wall Connector. A 50 amp circuit or as you noted a 40 amp circuit is more than adequate; either the 40 or the 50 amp circuit will enable you charge at up to 32 amps. When charging at 240V and 32 amps the Tesla Charging Screen will display that the vehicle is charging at 8kW. When charging at 8kW the Tesla Model Y can gain up to 29 miles in an hour of charging; at that rate most week days your charging needs would be handled in just over 1 hour, not more than 2 hours.

The EV charging web page does not fully disclose the charging rate of the (3) ZEFNET metered charging station options, only that the vehicle's build-in charger needs to able to charge at a minimum 4.5kW rate but does not state the maximum charging power level of the metered equipment. As an example, 4.5kW is barely half the charging level of the 32 amp example but still adequate. Estimated nightly charging time in your example would be 2 to 2.5 hours at 4.5kW. One benefit of purchasing one of the ZEFNET charging station is that a separate power meter is not required. The downside of this option is that no vehicle charging would be available outside of 11PM to 7AM (the web page does not state if this limitation only applies to weekdays or 7 days a week.)

The EV charging web page states that both the EV Storage Charge program and the EV Time of Use (TOU) program require a separate meter to be installed. The off-peak rates are almost identical; only the TOU program enables you to charge at other times. If the Power Cost Adjustment (PCA) is large part of the cost of electricity in your area then the EV Storage Charge program could save some $ but it is unclear in your case just how much. Example: Assuming you use 10kWh from the grid each weekday evening to charge the Tesla Model Y (assuming charging after 11:00 PM) this would cost $0.60/week day for the EV Storage Charge program and $0.63/weekday + PCA (cost to be determined) under the TOU program.

(If you set up the Tesla to charge using Delayed Charging you can have charging begin as soon as 11PM or even better set the Tesla to always complete charging by 7AM. If you are not usually home during the day during the work week then there will not be a need to be concerned about the Tesla needing to be plugged in to keep the battery pack warm during the winter.

As far as I am aware the Tesla Model Y will actively maintain the battery pack temperature from dropping below 32F if the Tesla is plugged in; If the Tesla is parked, not plugged in then the pack will not be kept warm, start to be warmed until the next time you start to drive or remotely turn on the climate control (this powers on the Tesla's climate control, other systems so the battery pack should start warming.) When you arrive home in the evening the battery pack will already be warm; the battery pack will begin to cool down but the pack will cool slowly due to the large 1000 lb thermal mass of the pack. Since your vehicle will be plugged in, under the EV Storage Charge Program when there is no option for charging until 11PM, the Tesla can actively warm the battery pack if needed starting at 11PM even if the actual vehicle charging will not start until several hours later., Delayed Charging can be set so the Tesla starts charging as late as possible and still finish by 7AM, i.e. the Tesla will start charging at 4:30AM or 5:00AM and complete charging by 7:00AM. I believe you can set a different charging schedule for the weekend if you want or if your charging needs are different for Friday night through Sunday night (charging outside of the 11PM to 7AM window would only apply to the TOU plan, not the Storage Charge plan.)

 

[seniorcitizen]

The 60 amp circuit is only a potential benefit for you if you plan to install the Tesla Wall Connector. A 50 amp circuit or as you noted a 40 amp circuit is more than adequate; either the 40 or the 50 amp circuit will enable you charge at up to 32 amps. When charging at 240V and 32 amps the Tesla Charging Screen will display that the vehicle is charging at 8kW. When charging at 8kW the Tesla Model Y can gain up to 29 miles in an hour of charging; at that rate most week days your charging needs would be handled in just over 1 hour, not more than 2 hours.

The EV charging web page does not fully disclose the charging rate of the (3) ZEFNET metered charging station options, only that the vehicle's build-in charger needs to able to charge at a minimum 4.5kW rate but does not state the maximum charging power level of the metered equipment. As an example, 4.5kW is barely half the charging level of the 32 amp example but still adequate. Estimated nightly charging time in your example would be 2 to 2.5 hours at 4.5kW. One benefit of purchasing one of the ZEFNET charging station is that a separate power meter is not required. The downside of this option is that no vehicle charging would be available outside of 11PM to 7AM (the web page does not state if this limitation only applies to weekdays or 7 days a week.)

The EV charging web page states that both the EV Storage Charge program and the EV Time of Use (TOU) program require a separate meter to be installed. The off-peak rates are almost identical; only the TOU program enables you to charge at other times. If the Power Cost Adjustment (PCA) is large part of the cost of electricity in your area then the EV Storage Charge program could save some $ but it is unclear in your case just how much. Example: Assuming you use 10kWh from the grid each weekday evening to charge the Tesla Model Y (assuming charging after 11:00 PM) this would cost $0.60/week day for the EV Storage Charge program and $0.63/weekday + PCA (cost to be determined) under the TOU program.

(If you set up the Tesla to charge using Delayed Charging you can have charging begin as soon as 11PM or even better set the Tesla to always complete charging by 7AM. If you are not usually home during the day during the work week then there will not be a need to be concerned about the Tesla needing to be plugged in to keep the battery pack warm during the winter.

As far as I am aware the Tesla Model Y will actively maintain the battery pack temperature from dropping below 32F if the Tesla is plugged in; If the Tesla is parked, not plugged in then the pack will not be kept warm, start to be warmed until the next time you start to drive or remotely turn on the climate control (this powers on the Tesla's climate control, other systems so the battery pack should start warming.) When you arrive home in the evening the battery pack will already be warm; the battery pack will begin to cool down but the pack will cool slowly due to the large 1000 lb thermal mass of the pack. Since your vehicle will be plugged in, under the EV Storage Charge Program when there is no option for charging until 11PM, the Tesla can actively warm the battery pack if needed starting at 11PM even if the actual vehicle charging will not start until several hours later., Delayed Charging can be set so the Tesla starts charging as late as possible and still finish by 7AM, i.e. the Tesla will start charging at 4:30AM or 5:00AM and complete charging by 7:00AM. I believe you can set a different charging schedule for the weekend if you want or if your charging needs are different for Friday night through Sunday night (charging outside of the 11PM to 7AM window would only apply to the TOU plan, not the Storage Charge plan.)

Thank you "jcanoe" for taking the time to respond. I am going to go with shared I am going to get one of these charger
11.5kW ZEFNET Single-Head Wall Mount — ZEF Energy
7.7kW ZEFNET Single-Head Wall Mount — ZEF Energy

It has a meter built into it so additional meter is not required.

Feel fortunate to find this community. I am learning a lot.

 

[jcanoe]

Thank you "jcanoe" for taking the time to respond. I am going to go with shared I am going to get one of these charger
11.5kW ZEFNET Single-Head Wall Mount — ZEF Energy
7.7kW ZEFNET Single-Head Wall Mount — ZEF Energy

It has a meter built into it so additional meter is not required.

Feel fortunate to find this community. I am learning a lot.

Either one would be an excellent choice (ClipperCreek (CC), CA, USA, makes some of the best EV charging station equipment available. The charging components of the ZEFNET units are clearly made by CC.) I would recommend getting the 7.7kW unit (lower cost than the 11.5kW unit and more than up to the task of charging your Model Y. (Over the 8 hour charging window the 7.7kW unit would be able to charge, replenish more than 200 miles (even up to 232 miles) of EV driving range to your Model Y. The 7.7kW unit would require a dedicated 240V 40 amp circuit. This unit is meant to be hard wired, installed by an electrician. The 11.5kW unit would require a dedicated 240V 60 amp circuit.

As previously noted the ZEFNET metered charging option does not provide for any charging outside of the off peak (assumed 11PM to 7AM) charging window. This also appears to be the case on weekends and holidays. On weekends this could be inconvenient. Since you currently have 2 other vehicles you would never be stuck at home without a way to charge until late in the evening.

 

[seniorcitizen]

The fact that I cannot charge over the weekends or holidays during daytime bugs me the most. I would have been willing to pay more for an occasional daytime charge. My electrician told me that he can put in a subpanel in the garage that can support 100 amps and two 7.7kW chargers. I will start with just one charger for now. I am getting quotes from a few other electricians who will tell me the cost difference between zefnet without external meter and Tesla gen 3 charger with external meter.

 

[jcanoe]

The fact that I cannot charge over the weekends or holidays during daytime bugs me the most. I would have been willing to pay more for an occasional daytime charge. My electrician told me that he can put in a subpanel in the garage that can support 100 amps and two 7.7kW chargers. I will start with just one charger for now. I am getting quotes from a few other electricians who will tell me the cost difference between zefnet without external meter and Tesla gen 3 charger with external meter.

Don't forget to investigate what the Power Cost Adjustment is likely to mean if you choose the TOU plan as it would apply to your energy cost, total monthly bill. With a 100 amp sub panel you can have the electrician install a second 240V circuit and 6-20 receptacle (rated for 240V and 20 amps.) You can purchase the Tesla NEMA 6-20 power plug adapter for $35 from the Tesla Store, this would enable you to charge at 240V/16 amps using the Tesla Mobile Connector that comes with every Tesla vehicle. That plug adapter/configuration would give you 12 or 13 miles of EV range replenishment per hour, enable you to charge at up to 16 amps on the 20 amp circuit. IOf course you could also just plug the Mobile Connector into a standard 120V 15 amp receptacle and charge at 3 miles per hour at the 8 amp setting, 4 miles if you can use the 12 amp setting (nothing else powered by the 15 amp circuit beside the Mobile Connector.) Don't pass on installing a low amperage 240V circuit; even a 6-15 (240V/15 amp) circuit will charge twice as quickly as a 5-15 (120V/15 amp) circuit, the electrician's time and cost would be the same except the double pole circuit breaker would cost a few $ more than for a 120V circuit.

 

[seniorcitizen]

Don't forget to investigate what the Power Cost Adjustment is likely to mean if you choose the TOU plan as it would apply to your energy cost, total monthly bill. With a 100 amp sub panel you can have the electrician install a second 240V circuit and 6-20 receptacle (rated for 240V and 20 amps.) You can purchase the Tesla NEMA 6-20 power plug adapter for $35 from the Tesla Store, this would enable you to charge at 240V/16 amps using the Tesla Mobile Connector that comes with every Tesla vehicle. That plug adapter/configuration would give you 12 or 13 miles of EV range replenishment per hour, enable you to charge at up to 16 amps on the 20 amp circuit. IOf course you could also just plug the Mobile Connector into a standard 120V 15 amp receptacle and charge at 3 miles per hour at the 8 amp setting, 4 miles if you can use the 12 amp setting (nothing else powered by the 15 amp circuit beside the Mobile Connector.) Don't pass on installing a low amperage 240V circuit; even a 6-15 (240V/15 amp) circuit will charge twice as quickly as a 5-15 (120V/15 amp) circuit, the electrician's time and cost would be the same except the double pole circuit breaker would cost a few $ more than for a 120V circuit.

I will need to understand what Power Cost of Adjustment means.

This is an excellent suggestion. Charge on the Zefnet at night most of the time and plug in directly on the 2nd 240V outlet for emergencies.

Thanks once again helping me.

 

[jcanoe]

I will need to understand what Power Cost of Adjustment means.

This is an excellent suggestion. Charge on the Zefnet at night most of the time and plug in directly on the 2nd 240V outlet for emergencies.

Thanks once again helping me.

The Power Cost Adjustment appears to be tied to the Energy Rate (the Energy Rate appears as a line item on your electric bill and is the cost you pay for 1kWh of electricity (this does not the distribution charges, i.e. power line infrastructure charges.)

If the electric utility has to pay more for the electricity it brings to your home based on demand, seasonal usage, other factors that the utility will pass on this cost to the consumer. More here: Electricity Rates by State (October 2020) | ChooseEnergy.com® You should expect to pay more for the electricity you use in the summer than in winter because the demand is higher in summer.

 

[user212_nr]

The fact that I cannot charge over the weekends or holidays during daytime bugs me the most. I would have been willing to pay more for an occasional daytime charge. My electrician told me that he can put in a subpanel in the garage that can support 100 amps and two 7.7kW chargers. I will start with just one charger for now. I am getting quotes from a few other electricians who will tell me the cost difference between zefnet without external meter and Tesla gen 3 charger with external meter.

The sub-panel is always a good idea.

All you need is to install a 14-50 outlet onto the sub-panel and then you will be able to charge during the day if you need it in an emergency, and you can keep the mobile charger in your car otherwise.

The Model Y comes with a "Mobile Charger" that can charge at 32A (50A socket) with this adapter:

Gen 2 NEMA Adapters

How does the car keep the battery pack warm during day time? Does it require to be plugged in? This is my main question.

The pack is not kept warm when the car is idle, and does not need to be warmed except while charging. Since you will have power while charging this is not an issue.

The only thing that runs when the car is unplugged is the computer (and a few other non-essential options related to interior climate), and the computer goes into lower mode after a few minutes, even if plugged in, if charging is finished.

 

[jcanoe]

The sub-panel is always a good idea.

All you need is to install a 14-50 outlet onto the sub-panel and then you will be able to charge during the day if you need it in an emergency, and you can keep the mobile charger in your car otherwise.

The Model Y comes with a "Mobile Charger" that can charge at 32A (50A socket) with this adapter:

Gen 2 NEMA Adapters



The pack is not kept warm when the car is idle, and does not need to be warmed except while charging. Since you will have power while charging this is not an issue.

The only thing that runs when the car is unplugged is the computer (and a few other non-essential options related to interior climate), and the computer goes into lower mode after a few minutes, even if plugged in, if charging is finished.

Do you know if the Model Y, other Tesla vehicles too, will maintain the temperature of the battery pack within an acceptable range while the vehicle is parked, plugged in, even if charging has been completed or is set to deferred? In winter this would be above 32F; in summer less than 90F or so. It would make sense to maintain the temperature of the battery pack in cold weather else there would be no regenerative braking available when you drive off in the vehicle until the battery warmed.

 

[user212_nr]

Do you know if the Model Y, other Tesla vehicles too, will maintain the temperature of the battery pack within an acceptable range while the vehicle is parked, plugged in, even if charging has been completed or is set to deferred?

As I understand it, the Model 3/Y does not do any battery temperature operations except while charging or pre-conditioning for supercharging. Plugged in or not makes no difference - Tesla does not run the car differently when it is plugged in. Only when the battery is <20% does Tesla restrict operations, and that could be plugged in or not.

Tesla understands that even though you are not plugged in now, you will be plugged in later, so they take any power they want out of the battery. It is no difference to them. It is minimal usage vs driving, so they do not worry about depleting the battery until it goes below 20%.

 

[jcanoe]

As I understand it, the Model 3/Y does not do any battery temperature operations except while charging or pre-conditioning for supercharging. Plugged in or not makes no difference - Tesla does not run the car differently when it is plugged in. Only when the battery is <20% does Tesla restrict operations, and that could be plugged in or not.

Tesla understands that even though you are not plugged in now, you will be plugged in later, so they take any power they want out of the battery. It is no difference to them. It is minimal usage vs driving, so they do not worry about depleting the battery until it goes below 20%.

Thank you for your explanation. I have observed my Tesla Model Y, I assume other Tesla models will do this too, actively cool the battery pack while the vehicle is parked (unplugged) after having been driven. The battery pack state of charge has always been above 20%. What about if the temperature of the pack starts to drop below 32F while the vehicle is parked, will the pack temperature be automatically regulated to be above 32F? If not, looking ahead to this winter, when I turn on the climate control via the Tesla App, about 20 minutes prior to driving my Model Y, will the battery pack be warmed at the same time that the climate control is warming up the passenger cabin? My Model Y is usually parked inside my garage. Usually the garage temperature remains above 30F but I have observed the temperature inside my garage as low as 15F in very cold weather (for this part of Maryland.) Will I have to start off each short trip without regenerative braking in this situation (most of my trips are less than 5 miles)?

Thank you.

 

[user212_nr]

Thank you for your explanation. I have observed my Tesla Model Y, I assume other Tesla models will do this too, actively cool the battery pack while the vehicle is parked (unplugged) after having been driven.

Some people say this, I've not confirmed this. There is a setting to maintain the interior climate below 50 C for 12 hours after driving (A/C or fan only), and I think it is default, but this is for the interior only.

My understanding is that Tesla will allow the battery to drop well below 0F, plugged in or not, and this is not harmful.

 

[jcanoe]

Some people say this, I've not confirmed this. There is a setting to maintain the interior climate below 50 C for 12 hours after driving (A/C or fan only), and I think it is default, but this is for the interior only.

My understanding is that Tesla will allow the battery to drop well below 0F, plugged in or not, and this is not harmful.

I understand about Cabin Overheat Protection (this feature can be set to use the AC or just use the fan to reduce the cabin temperature when above 105F. Cabin Overheat Protection is only active for the first 12 hours after you park the vehicle unless you later remotely turn on the vehicle then this resets the 12 hour clock.