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Question on powerwall mode
- Thread starter Ngenn
- Start date
I suspect there is something wrong with the power measurements you're seeing. Can you turn on the house load in the chart too so we can see what that shows? You should probably ask Tesla double-check your CT placement and configuration. The numbers in your chart don't add up. (Note that at 8pm, your Powerwalls were discharging 5.5kW and your grid was supplying the same, meaining your house would have to have been using 10.1 kW then. At 8pm, your Powerwalls go to standby and your grid draw doesn't change, meaning your house load would have had to coincidentally drop by the same 5.5 kW for the numbers to make sense.)
Edit: once Tesla fixes the CTs, I think your system should behave the way you want it.
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My last true-up with Powerwalls had a net usage over 10,000 kWh. I really need to double my solar to cover my EV charging and future A/C install. No worry about poor excess compensation here.
Feel like I’m going to be in the same boat. Debating if another powerwall is worth doing (have2) since I’m not sure the rest of my roof will be as productive and I do have some excess going to grid.
Hi, sorry I'm a newbie and I don't know what "CT" refers to?
If the CTs are off/wrong, is that something I can fix/reboot/reset myself?
I've posted the 4 separate charts to break down that day. Hope that helps.
(At 8:00 pm, it was just the Grid supplying the Household with about 5.3 kW of energy; the PowerWalls were not on at that exact time.)
thanks,
Bobby
CT’s are Current Transformers. Those are the devices that are put over the wires in your system to read the amount of current passing through the wires.
Probably not. ‘Wrong’ could mean that they were put over the incorrect wires, installed backwards, or identified incorrectly in the software. None of those are likely something that would be safe to attempt to fix on your own
In this case it would actually be a little easier to read the graphs if they were all on one and not in four separate charts, but I did look through them and everything looks fine to me. Your house is definitely using a lot of power. 88.8kW is definitely on the high side for a home to use, but it’s not impossibly high.
There is more than one way for the CTs to be connected wrong. Here's what I'm seeing: house load just before 8 pm looks to be about 5 kW. The power being supplied from the Powerwalls at that time is about the same, as is the grid, so 10 kW total. That means there is an extra 5 kW coming from somewhere. I'm guessing the CTs that are configured as grid are actually measuring load or something like that.
I think it's pretty clear that there is a problem with the CT configuration. Tesla should be able to figure out exactly what is wrong.
I don’t think that’s the case. Just before 8PM the house load was about 5kW and the powerwalls were supplying the house 5kW at that time, but then it switched from peak to off peak. At that point the powerwalls stopped supplying power to the house and the house started drawing 5kW from the grid. They didn’t overlap and both provide 5kW at any point. That was just the point where it transitioned from one to the other. This is totally normal and expected behavior for the mode that he is in.
My mistake - I misread the chart. I thought I saw an overlap before 8pm, but realize now that was my reading error, not what's in the chart.
If it's not a CT issue, I am also baffled because I've been running cost savings for more than a year without ever seeing this behavior.
Ok; thanks guys!
Thank you BrettS for explaining CTs, and thanks to both cwied and BrettS for helping look at my graphs.
cwied: Just curious: when you first turn on your PW (or when you first started using TBC Cost Saving mode), did it immediately start doing what it's doing for you now? Or did it take a few days or weeks to learn your usage and eventually settled on your current behavior? (Am I correct to assume that your PowerWalls are discharging during your Peak, and allowing you to send 100% of your Solar to Grid at Peak?)
I've called Tesla Energy support, and requested an escalation to Level 2 support.
I'll let you guys know what I find out!
Thank you BrettS for explaining CTs, and thanks to both cwied and BrettS for helping look at my graphs.
cwied: Just curious: when you first turn on your PW (or when you first started using TBC Cost Saving mode), did it immediately start doing what it's doing for you now? Or did it take a few days or weeks to learn your usage and eventually settled on your current behavior? (Am I correct to assume that your PowerWalls are discharging during your Peak, and allowing you to send 100% of your Solar to Grid at Peak?)
I've called Tesla Energy support, and requested an escalation to Level 2 support.
I'll let you guys know what I find out!
Yes, it immediately started offsetting all usage during peak. In my case, the only thing the system appears to "learn" is how far to charge up before the peak rate.
I've attached a chart of my system's behavior yesterday. I am on PG&E's E-6 rate which has off-peak until 10am, partial until 1pm and then peak from 1-7pm. My reserve is currently set to 60%. You can see it decided to charge up for the whole part-peak period and then switched over to discharging for the whole peak period. At 7pm, it goes to standby when the peak period ends. During the spring when we hadn't used the AC yet, it would only charge to 30% over reserve in the morning.
One thing to note is that I got my Powerwalls before TBC existed, so my start-up experience could have been different than yours for that reason.
Likely that’s when he started charging his EV. Either that or he has a decorative tesla coil in his back yard that the uses in the evenings.
I'm using the influxdb/telegraf/Grafana setup that someone posted here some time ago. I've tweaked it to provide higher resolution (10s) charts. I'll see if I can find the original post and link it here.
And yes, my usage jumped at 7pm because of car charging.
Yep, it's based on the first one. Here's the thread: New Powerwall Monitor
I'm running it in a Linux VM on my NAS server instead of on a Raspberry Pi, though.
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