Power Management

[Homestead]

My new CT is being charged in my carport. I installed a 48 amp circuit for this alone. I just got my first electric bill. It is still a lot of money. For the first month I had a zero energy charge, a generally green power supplier that is currently fully offset by my 5.1 KW solar array in the yard. But the local utility, Eversource, acts as a giant battery for me. I produce solar electrons during the day, but charge my CT starting at midnight. So I am able to get back “my” electrons from that energy supplier, but I have to pay for the privilege of the utility delivery service. That is called the Demand Charge. Because I am a commercial operation, my bill is divided between energy supplier and utility. If no solar system, those two charges would be roughly equal. Now energy is zero, but demand charge is significant.

so today is reprogrammed the CT to charge at a slower rate, only 30 KW. That means it will take somewhat longer to recharge the battery, but my costs could be 1/3 less. My question is how do I set the numbers. I start the charge by 6pm and I want it fully charged by 6 am. I usually charge when thebattery is near 50% and I top it at 80%. How can I calculate the energy required to bring it up each night. Can I set The charging rate lower and save more Demand Charge? Or do I do it by trial and error?

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[Woodrick]

I believe that you can set departure time or an off-peak time.

A 30% drop in charge is only about 35kW, so your 30A setting should be complete in about 2 hours.

So even at 30A (which is I think what you meant, not 30kW), that's 7kW or about 5 hours, so starting at midnight should be plenty.
In other words, you may be overthinking it.
Are you paying a ToD rate? If not, just let it start when you plug in. You could decrease the charge rate even more, if that would help.

 

[Homestead]

If I want to set the charging rate to 30 amps, or less, the CT defaults back to 48 amps every day. If I once forget the find the screen that sets the charging rate, then i am screwed for another month. Is there a way to tell the truck that the new maximum should be lower than the highest possible rate as a permanent instruction?

 

[CyberGus]

I set my charge rate to 5A while I’m away from home, it has. It reset itself.

You could set the WC to 30A max.

 

[Homestead]

Sorry, but what is the WC? Water closet? Waste container?

 

[Homestead]

The CT should be able to do this instead of greedy feeding at the maximum power rate, costing me and the environment top dollar, it could easily calculate the minimum power draw so it is fully charged when next needed. How about software upgrade? My last power bill was over $220 for a partial month. This could easily be cut in half.

 

[Shrey]

Sorry, but what is the WC? Water closet? Waste container?

Wall Charger

 

[mongo]

If I want to set the charging rate to 30 amps, or less, the CT defaults back to 48 amps every day. If I once forget the find the screen that sets the charging rate, then i am screwed for another month. Is there a way to tell the truck that the new maximum should be lower than the highest possible rate as a permanent instruction?

Instructions for Wall Connectors are halfway down the page
https://www.tesla.com/support/charging/product-guides

 

[Woodrick]

If I want to set the charging rate to 30 amps, or less, the CT defaults back to 48 amps every day. If I once forget the find the screen that sets the charging rate, then i am screwed for another month. Is there a way to tell the truck that the new maximum should be lower than the highest possible rate as a permanent instruction?

Set your wall charger back. Then if a different car plugs in, it doesn't cause an overage either.

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