Tesla Model S and 3 Best Charging?

[d21mike]

I have been using a 14-50 Plug on 50a Circuit for my S for the last 2 years. I just got a Model 3 and decided to put in 2x Load Balancing Wall Chargers on a 60a Circuit so I can charge at the same time. Max will be 48a. (removing 50a).

I currently schedule charging between 10pm and 8am using TOU-D-B $0.10 / kWh.
(at some point will have to change to TOU-Prime with $0.12 / kWh overnight).
Last month before Model 3: Super off peak 448 kWh with a total of 1,027 kWh for $232. Start of summer so will be higher. The Model 3 will probably be 50% more off peak then I use now with just the Model S.
I use overall about 1000 kWh per month. My bill average is $200+/month
I am adding Tesla Solar (8kw - 12kw) with 2 PowerWalls.
My On Peak is 2pm - 8pm $0.48 / kWh. (TOU-Prime will be 4-9pm and $0.40).

My other big usage is with the AC. During the summer 3 months is around double my normal usage. It is on a 40am Circuit but "I think" only draws 30a?

I assume the Power Wall will backup everything but Tesla Charging and AC when there is a power failure.

MY QUESTION:
Would I only use the Power Wall's Daily for the everything except Tesla Charging and AC as well? Meaning I would expect to generate "Credits" during the day and use my power wall for On Peak everything else and credits for the Car Charging?
We both work from home so I could switch to charging during the day instead of at night if the Solar can provide enough power to charge my car and also run the house and charge the Power Wall. What would my best option for Charging the cars?

 

[ewoodrick]

I don't think that you are going to get much of a ROI on the config. Every thing else isn't much of a load of a load.
If you had solar, that would be one thing, but you seem to be simply buying high and selling low.
If there was a great ROI, wouldn't every one be doing it?

 

[d21mike]

I don't think that you are going to get much of a ROI on the config. Every thing else isn't much of a load of a load.
If you had solar, that would be one thing, but you seem to be simply buying high and selling low.
If there was a great ROI, wouldn't every one be doing it?

Sorry I was not more clear. But I am talking about getting Solar with a PowerWall. I agree if there is no way to offset my Tesla Charging. I was hoping via credits or charging during the day time I could pay for the EV Charging with Solar? If I did not have EV Charging I would only be averaging about $160 per month instead of $200-$230 (with second Tesla). Regarding the Battery part of the investment it partially is to prevent power outages. I do not get a lot of them but they do come from time to time at and pretty inconvenient when you work from home.

 

[d21mike]

Been watching Youtube videos trying to find out if I can use Solar to Charge your Tesla(s) and provide power for other things. And when is the best time to charge the Tesla if you work from home and have options of when to charge.

Given a 12kw Solar System and trying to charge a Tesla with 40a or 48a.

How much of the charge would come from Solar and how much from the Grid? Let's say at the best part of the day for Solar. Maybe 10am-11am? I think Tesla Solar App shows how much is going to the House (for Tesla and other things) and how much is either going to the Grid or coming from the Grid. And if you have a Power Wall how much is going to the Power Wall?

Has anybody here done this?

The following video was a interesting pro-solar with Tesla's but did not answer my question.

Interesting Video:

 

[mongo]

@d21mike Here's a thread where they have a custom piece of software to control charging when solar is available.
Effect of Frequent Stop/Start Charging

 

[d21mike]

@d21mike Here's a thread where they have a custom piece of software to control charging when solar is available.
Effect of Frequent Stop/Start Charging

I currently use TeslaFI to schedule charging during Super Off Peak (10pm - 8am) so familiar with the API Concept. Interesting idea of charging during the day based on the status of the sun. I read another person saying that would be helpful to be able to change the AMP's the car is pulling (like multiple wall charger load balancing) but the API does not have this available. Maybe best would be for the Tesla App to adjust the amps based on how much solar is being generated since it has access to both. Maybe say whatever is left over allow the car to take and if any leftover after that send it to the Powerwall?

I just read on another thread where the person decided to start charging at 11am but have the car set to pull only 20a so he would not be pulling from the Grid.

But multiple other people have said they send extra power back to the Grid at the higher cost during the day and they charge at off peak at a lower rate. This would probably work for me since I believe SCE has Net Metering. I think SCE will soon force me off of my TOU-D-B plan to the TOU-PRIME which does not start the peak time until 4pm instead of 2pm. But I guess if you put send back to the Grid at a cost of at least how much you have to pay for it then it should be the same as charging directly from Solar. Right?

My question to anyone that has figured this out, what are they doing? Maybe different in different parts of the country and maybe different if you are not home during the day so would have to charge at night no matter what.

 

[mongo]

I currently use TeslaFI to schedule charging during Super Off Peak (10pm - 8am) so familiar with the API Concept. Interesting idea of charging during the day based on the status of the sun. I read another person saying that would be helpful to be able to change the AMP's the car is pulling (like multiple wall charger load balancing) but the API does not have this available. Maybe best would be for the Tesla App to adjust the amps based on how much solar is being generated since it has access to both. Maybe say whatever is left over allow the car to take and if any leftover after that send it to the Powerwall?

I just read on another thread where the person decided to start charging at 11am but have the car set to pull only 20a so he would not be pulling from the Grid.

But multiple other people have said they send extra power back to the Grid at the higher cost during the day and they charge at off peak at a lower rate. This would probably work for me since I believe SCE has Net Metering. I think SCE will soon force me off of my TOU-D-B plan to the TOU-PRIME which does not start the peak time until 4pm instead of 2pm. But I guess if you put send back to the Grid at a cost of at least how much you have to pay for it then it should be the same as charging directly from Solar. Right?

My question to anyone that has figured this out, what are they doing? Maybe different in different parts of the country and maybe different if you are not home during the day so would have to charge at night no matter what.

Good point. I can see Tesla integrating charging into the power management app and achieving higher granularity.
If it is a straight net usage, then yeah only time shifting. If different rates, better to charge at night.

 

[d21mike]

@d21mike Here's a thread where they have a custom piece of software to control charging when solar is available.
Effect of Frequent Stop/Start Charging

I found this video of a guy doing something similar by using the Tesla API and the Power Wall API. I think an important issue to be able to tell the car to reduce the amp's it is pulling instead of just stopping the charging and then starting again at the same rate.

 

[mongo]

I found this video of a guy doing something similar by using the Tesla API and the Power Wall API. I think an important issue to be able to tell the car to reduce the amp's it is pulling instead of just stopping the charging and then starting again at the same rate.

Yah. In multiple HPWC setups, the communication link sets the charge limit, so Tesla may come out with a box that makes all the WCs controlled.