My system does not discharge during Off-Peak at all. Some people have had trouble with this though. I don't know what is different about their system that allows Off-Peak discharge.
+1. My system behaves the same way with undersized solar. My system attempts to peak shave using power stored up from the weekend, and never discharges off-peak.
According to the Tesla's updated Time-based Control page, it may discharge during off-peak if it thinks it needs room to storage excess solar energy for the upcoming day. It certainly happens to my PW.
I have 27kWh of battery and 4.3kW (5 to 25kWh/day) of solar. Certainly if your solar ratio is higher, the behavior could be very different. It probably also depends a lot on whether you have Off-Peak generation or not. My weekday generation is all Part-Peak or Peak, so that also affects the Powerwall behavior.
I have 9.24 kW solar and 2 PW. Whether it will discharge during off-peak depends on my PW's SoC. e.g. last night, SoC is 20% (10% reserved). It didn't discharge off-peak. Only started to discharge when it was peak. I have no morning shoulder. Last Fri, SoC is 77%. It discharged during off-peak, about 2 hours before peak started.
My system also starts discharging early at higher SOC, before Peak starts. However, in my case, that is a shoulder period which earns me significantly more money in NEM credits than Off-Peak. I have written about this in other threads. This is new behavior that started this winter and I first noticed it in the Spring. Last Summer in TBC-Balanced, it would never start discharging until the Peak period started. Instead it would just charge to full and then to to Standby until Peak started. It does save me a little more money by earning additional Part Peak NEM credits late in the week and replacing that energy with Off-Peak generation on Sat/Sun. In good weather, that is clearly the right strategy, but today the weather is bad and I would rather save the energy for backup, so I raised the Reserve to prevent discharge while the solar is generating. I will drop the Reserve again when the sun goes down so I can ride out the Peak period without grid consumption.
Am curious, I got 2 quotes of $11,500 and $16,000 to install 1 powerwall.
My install timeline (so far)
I went to the Tax Assessor's site & found the issuance of the permit
before Tesla could notify me......
This is late, but remember, you're going to lose 5%+ just on gathering dust, especially over summer; about 0.4% per year on natural panel degradation; 66%+ when it's cloudy; 0.6% for ambient temperatures higher than nominal (about 25C). It's going to be up there for warranty years of 25? years.
