Powerwall Control and Limitations
This article covers common questions about controlling Tesla Powerwall systems through Teslemetry, including the Tesla Fleet API limitations, workarounds, and troubleshooting tips.
Overview
Teslemetry provides control over Tesla Powerwall systems through the Tesla Fleet API. However, there are important limitations to understand, as Tesla restricts certain capabilities.
Common Questions
Can I force my Powerwall to discharge the battery?
No, there is no direct API command to force discharge a Powerwall. This is a Tesla Fleet API limitation, not a Teslemetry limitation.
Only Virtual Power Plants (VPPs) have the ability to force discharge a Powerwall through their special API access.
Workaround - Tariff Price Manipulation:
You can encourage discharge behavior by manipulating the Time of Use (ToU) tariff settings. When the export/sell price exceeds the import/buy price by a sufficient margin, the Powerwall will autonomously decide to export to the grid.
How do I force charge my Powerwall?
Set the backup reserve to 100%. This is the only reliable method to force the Powerwall to charge from any available source (grid or solar).
In Home Assistant, you can use the number.{powerwall_name}_backup_reserve entity and set it to 100.
What backup reserve percentages can I set?
The backup reserve can be set to:
- 0% to 80% - Any value in this range
- 100% - For force charging
Note: Values between 81% and 99% are not supported by the Tesla Fleet API.
Why does grid charging keep turning off automatically?
There are several possible causes:
- VPP Enrollment: If your Powerwall is enrolled in a Virtual Power Plant program, the VPP may be overriding your settings
- Tesla System Issues: Tesla occasionally has server-side issues that cause settings to revert
- Conflicting Automations: Multiple services or automations may be changing the same setting
How to troubleshoot:
- Open the Tesla app
- Navigate to your Powerwall > Settings
- Tap the clock icon in the top right corner
This shows the command history and reveals which application or service made each change.
Powerwall Entities in Home Assistant
Domain | Name | Description |
|---|---|---|
Number | Backup reserve | Set backup reserve (0-80, 100) |
Sensor | Battery power | Current battery power flow |
Sensor | Energy left | Remaining energy in kWh |
Sensor | Grid power | Current grid power flow |
Sensor | Island status | Grid connection status |
Sensor | Percentage charged | Battery state of charge |
Sensor | Solar power | Current solar production |
Select | Allow export | Grid export rule |
Select | Operation mode | Self-consumption/Backup/Autonomous |
Switch | Allow charging from grid | Enable/disable grid charging |
Switch | Storm mode | Enable storm watch |
Known Limitations
Tesla Fleet API Limitations
- No force discharge capability - Only VPPs can force battery discharge
- Backup reserve range - Only 0-80% and 100% are valid values
- No individual Powerwall data - The API reports the entire energy site as a single unit
- No local API access - Powerwall 3 removed the local API
VPP Interference
If you're enrolled in a VPP program (Tesla Virtual Power Plant, Amber SmartShift, etc.), the VPP may override your settings at any time.
Related Resources
Updated on: 01/02/2026
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