System is switching from grid to PowerWalls during free off-peak period.

[getakey]

Personally, I use Balanced Mode and it discharges in the morning too. The OP's charts clearly show it happening and he says he has been using Cost Saving. Why? It's "the algorithm". All we can do is report the behavior we see.

I think it is the CTs not right as someone else suggested.

 

[miimura]

I think it is the CTs not right as someone else suggested.

That is definitely not the case with my system. The system is simply deciding that there is sufficient stored energy to use some to power the house during Off-Peak. To me, it's wasted battery cycles and round trip losses.

Take a look at this chart. During Off-Peak it discharged 1.0kWh before the solar started generating. After it stopped discharging, it started charging, causing grid draw when it could have just delayed charging and let the solar power the house to the extent that it could. Basically, it looks like the spike of usage when we got up and made breakfast made the the system change its mind about how much surplus energy there was. In the end, it was still fully charged before the Part-Peak started at 3pm.

 

[getakey]

That is definitely not the case with my system. The system is simply deciding that there is sufficient stored energy to use some to power the house during Off-Peak. To me, it's wasted battery cycles and round trip losses.

I agree that it is wasted. It just does not make sense to me at all and I've never seen it. Do you have shoulder set up in your app or is it just Off and Peak? If you have Shoulder, your situation could even be worse than round trip losses. You could be charging during Shoulder and discharging during Off Peak

 

[miimura]

I agree that it is wasted. It just does not make sense to me at all and I've never seen it. Do you have shoulder set up in your app or is it just Off and Peak? If you have Shoulder, your situation could even be worse than round trip losses. You could be charging during Shoulder and discharging during Off Peak

I edited my post to add a paragraph and a chart. I think it answers your questions.

 

[getakey]

I edited my post to add a paragraph and a chart. I think it answers your questions.

wow - that is weird to discharge in the morning like that

When is your Shoulder? Is it charging PW during any part of the Shoulder? I have Shoulder in my rate plan, but I eliminated it in the Tesla App so that I only have Peak and Off

 

[miimura]

wow - that is weird to discharge in the morning like that

When is your Shoulder? Is it charging PW during any part of the Shoulder? I have Shoulder in my rate plan, but I eliminated it in the Tesla App so that I only have Peak and Off

This is PG&E EV2-A. Shoulder is 3-4pm and 9pm-12mid. It is usually full before the shoulder starts. It is varying the amount of solar used for charging - between All Solar and Surplus Solar to hit the target. If I was designing it, I would probably just calculate the fixed kW required to fill it at the end of Off-Peak and lock it there.

 

[getakey]

got it
At least the PW is charging from 3 to 4

 

[astrotoy]

This is PG&E EV2-A. Shoulder is 3-4pm and 9pm-12mid. It is usually full before the shoulder starts. It is varying the amount of solar used for charging - between All Solar and Surplus Solar to hit the target. If I was designing it, I would probably just calculate the fixed kW required to fill it at the end of Off-Peak and lock it there.

I am using PGE EV2-A. Can I charge my powerwalls during the off peak times? I see that happens when we get a Storm Watch warning and the powerwalls fill up to 100% in anticipation of a power outage. However, when we have less sunlight or higher air conditioning needs during the peak and shoulder times, my powerwalls get depleted (to my 20%) reserve before the end of that time. It would make more sense to charge the powerwalls during the off peak times (after midnight) and if the powerwalls are filled to 100%, then if there is extra solar power available, the grid can be charged. The powerwalls can then be used during the peak and shoulder times and not run out so early. Basically that effectively partly arbitrages the grid power. Thanks.

 

[aesculus]

I am using PGE EV2-A. Can I charge my powerwalls during the off peak times? I see that happens when we get a Storm Watch warning and the powerwalls fill up to 100% in anticipation of a power outage. However, when we have less sunlight or higher air conditioning needs during the peak and shoulder times, my powerwalls get depleted (to my 20%) reserve before the end of that time. It would make more sense to charge the powerwalls during the off peak times (after midnight) and if the powerwalls are filled to 100%, then if there is extra solar power available, the grid can be charged. The powerwalls can then be used during the peak and shoulder times and not run out so early. Basically that effectively partly arbitrages the grid power. Thanks.

Probably not since Tesla has assumed you took the federal solar tax credit for the Powerwalls. This means that ONLY solar power is supposed to be put in there.

I have yet to find a person in PG&E territory that was successful in getting this allowed, even when they did not have solar.

The Storm Watch was a special case that I assume Tesla believes was a rounding error to the total amount of energy managed by the Powerwalls so it was allowed.

 

[miimura]

I am using PGE EV2-A. Can I charge my powerwalls during the off peak times? I see that happens when we get a Storm Watch warning and the powerwalls fill up to 100% in anticipation of a power outage. However, when we have less sunlight or higher air conditioning needs during the peak and shoulder times, my powerwalls get depleted (to my 20%) reserve before the end of that time. It would make more sense to charge the powerwalls during the off peak times (after midnight) and if the powerwalls are filled to 100%, then if there is extra solar power available, the grid can be charged. The powerwalls can then be used during the peak and shoulder times and not run out so early. Basically that effectively partly arbitrages the grid power. Thanks.

As @aesculus said, Tesla doesn't allow you to grid charge whenever you want. Before I got Powerwalls, I assumed I would be able to arbitrage the full capacity of the Powerwalls every day, but it's just not the case. You are limited by your consumption during the higher rate periods and your solar generation during the lower rate period.

I have just hit the point in the seasons where my solar is not generating enough to power me through from 3pm-midnight. I started to draw grid power about 10pm on 3 of the last 5 days. I also just raised my Reserve from 40% to 50% because they were not reaching 90% before starting to discharge. Yesterday, I had already raised the Reserve and the max SOC was only 85%. Through the Winter, I always want the batteries to absorb all the solar possible, but have as much Reserve as possible. That means that I gradually raise the Reserve to 75% as Fall progresses to Winter and then drop it as Winter turns to Spring and the PWs start to hit 100% again.