Powerwall 3 - discussion on current control strategies

[thepebbler]

Background

This may go nowhere, but with the recent (hopefully temporary) need to use an external automation to control the PW3 based on current predbat.status value, I noticed the template and behaviours weren't 100% as expected..

1. When charging, it flips operation mode, ending up in 'backup' mode.. on my PW3 (latest firmware) this limits charging to a fairly low value, but if left in self consumption mode, I get a full sustained 10kW (PW3 + 2 ext units). I don't know the reason for this.
2. When in 'demand' mode the default template is export 'never' which throws away all the good excess solar not going in to the battery, I've set that to pv_only when in demand and that works as expected.

So, in the world of Tesla and their APIs/Firmware, I think I'd start a discussion to just check what current thinking is on the latest control modes/methods to achieve predbats desires..

Predbat Status 'Modes' Automation

My automation is triggered on predbat.status which gets updated every 5 mins by predbat even if the status value stays the same which gives a great 5 minute 'tick'..

I simply work out form the predbat 'status' what the desired settings should be for that mode and then methodically go through and update each Fleet Integration entity if it is not in the desired state. I've also added a 5 second delay after each one as I did notice firing them all off in one automation run had the Fleet integration sometimes flip a value back which would then be caught 5 minutes later when the automation runs again..

(I have another automation for tariffs)

The logic table is:

predbat.status	target_mode	target_reserve	target_export	target_grid_charging
'Charging'	autonomous	100	pv_only	on
'Hold charging'	backup	100	pv_only	off
'Hold exporting'	backup	100	pv_only	off
'Exporting'	autonomous	0	battery_ok	off
'Demand'	self_consumption	0	pv_only	off
Any other state (else)	None	None	None	None

There are a lot of questions in my mind about robustness of this approach, as there are many things I'm probably not aware of:

1. Are there any interactions that need an order of precedence on which entities need updating in a certain order?
2. I have tried to explicitly set values even if they don't necessarily make a difference or sense, its just my SW Eng background, but could those have some side effects.
3. Are these even the latest desired control methods? They seem to work for the day or so I've been running them..

Tariff Automation

This was split out as it has different requirements, it's triggered on Predbat.status again, so gets a nice 5 minute tick..

Effectively It checks to see if the status has changed, if it has and its one that needs a REST call (as per the template services), it immediately calls that..
However, every 15 minutes (or 3 triggers) even if the status hasn't changed, it reaffirms the REST call.. This is necessary since predbat's instructions for the Export Now tarriff have a narrow window of higher Export costs which is great, it puts pressure on the powerwall to export now.. but you have to keep updating that..

All seems good, but questions of course!

1. I did this to stop spamming the Tesla Fleet API every 5 mins, I've chosen 15 mins as refresh, but no idea if that is necessary but didn't know if the Powerwall logic in anyway recalculates things everytime a tariff refresh is done and therefore if there are any side effects..
2. I explicitly set a tariff no matter what the predbat.status, so not just on status change and when in export/demand etc.. but I feel possibly uneasy that explicitly setting tariffs is a good idea, although it is predominantly the fixed one that discourages discharge..

predbat.status	REST Command Fired
'Exporting'	rest_command.tesla_api_set_export_now_tariff
'Demand'	rest_command.tesla_api_set_iog_custom_tariff
'Charging'	rest_command.tesla_api_set_iog_custom_tariff
'Hold charging'	rest_command.tesla_api_set_iog_custom_tariff
'Hold exporting'	rest_command.tesla_api_set_iog_custom_tariff
Any other state	None

Feel free to chime in with your wisdom, as things change and firmware updates/side effects become known, I'd like to think we can keep the lastest information somewhere in this github to help new people starting out..