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Powerwall 2 - Time Based Control

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I dont agree with your first sentence and “obviously be better off”. its just not that simple, which I’m sure you know. I have 30kw solar, 3 pw2, 2 tesla, and an energy efficient house. I now have a year of data with this full setup, and I have the added benefit of being able to charge cars during the day With excess solar. I’ve always been on a single but expensive flat rate of around 32c and exports are dropping to 12.4c. i have a good solid model for determing the best power company for my circumstance, and the point is whats right for me is not so much the next person. Recently I adapted my model to use the pw2 data to see if time of use is better. I ran the scenario with several companies, and my conclusion was that not only would I be significantly worse off, but life wouldnt be as simple on the power front.
Assume you have multiple AC coupled inverters? Are the inverters behind the gateway? If so how many inverters remain charging the PW's if your grid is out?
 
What I need to figure out is how to have the Off-peak start at 0:00 instead of 23:30. The thirty minutes of charging it can do from 23:30 will be at 13.78c/kWh rather than the 6.94c/kWh from midnight. If it's going to fill the battery so I export to the grid I'll be losing.

Just drag the off-peak start slider (blue with the empty circle) all the way to the left to set it to 00:00 rather than trying to push it all the way to the right.
 
Now that I have my off-peak set to 00:00-04:00 I think I'm all set - at least for weekdays.

My hope is that if it only charges the battery from 00:00-04:00 at 6.94c/kWh any excess solar going to grid at 7c/kWh is a sort of win - although given the battery is not 100% efficient, I'd be better off avoiding exporting. I think that playing with the start/end of peak and off-peak might get me to a position where even though the battery gets to 100%, that I have discharged some of that before I get to an excess solar situation.

I'm also thinking that while I'm in a chain of sunny days, don't need net grid supply, and the battery will still get charged, there will be less charging required at a later point (chain of wet/cloudy days) that it should net out.

I'll call Powershop on Monday and see how long it takes to switch my tariff. Hopefully, I can do it immediately rather than waiting until the end of the billing cycle (17 May).
 
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Assume you have multiple AC coupled inverters? Are the inverters behind the gateway? If so how many inverters remain charging the PW's if your grid is out?
I have micro-invertors, so one per panel but they push out 240v. They are connected at the gateway as 7 circuits. As its 240v you just use normal amperage calcs for the cable size. During an outage all invertors remain live, and charge the powerwalls, however only one phase can be powered in an outage, which is annoying as the microinvertors are all active. Powerwall 2 gateway isnt 3 phase optimised. Fortunatley I built the house recently and with one phase having all the critical power elements.
 
Just a bit of an update. In theory, I switched over to the EV Time-of-use tariff yesterday (or so Powershop tell me). I'll have to wait for my next bill to be sure (and argue with them if I didn't).

However, I actually switched to the Time Base Control (Cost Savings) a couple of weeks ago so I could watch how it works. I realise it will have been costing me a little more due to the inefficiencies of the batteries but at least I could see how well it works.

So far, it has been a great success!

On weekdays, the batteries are at 100% by the end of the cheap period so most of the charging would have been at 6.94c/kWh. Between 04:00 and 07:00 there's a bit of grid usage (at 13.78c/kWh) and battery usage so by 07:00 the batteries can be down to 80%. There's no grid usage (except due to errors in the CT Clamp readings) between 07:00-23:00 (23.12 and 32.33c/kWh). A small amount of grid (13.78c/kWh) and battery usage occurs between 23:00 and 00:00, then it all starts up again.

Weekends are much the same but I only have Peak and Off-peak configured.

I've basically had no solar output to the grid (other than a couple of hundred Wh per day which again is probably slight errors).

I did have one weekend morning where the batteries were at 100% at 7am. I got worried and dumped a bit to the car but then realised the forecast was for an overcast day and the AI had factored it in. I also forgot my wife would be running the dryer much of the day. Even so, I still had plenty of charge in the batteries to get to the next charging cycle.
 
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