Tesla Fleet: Powerwall Battery Charged sensor returns totally incorrect values

### The problem

See also issue #181365. The Powerwall Battery Charged sensor returns totally incorrect values. My Powerwall charges overnight, overnight, from a low SoC (between 5 and 15%) up to a high SoC (always 100%). For example:

In the above example between midnight and 6am it charged from 20% to 100%, which equates to ~11.6 kWh charged. Yet for the same period the Battery Charged sensor shows this:

Which is clearly not correct.

### What version of Home Assistant Core has the issue?

core-2026.8.3

### What was the last working version of Home Assistant Core?

_No response_

### What type of installation are you running?

Home Assistant Container

### Integration causing the issue

Tesla Fleet

### Link to integration documentation on our website

https://www.home-assistant.io/integrations/tesla_fleet/

### Diagnostics information

[config_entry-tesla_fleet-01KTZWR3JANTM8WKHZ5SBAG3AD.json](https://github.com/user-attachments/files/32140205/config_entry-tesla_fleet-01KTZWR3JANTM8WKHZ5SBAG3AD.json)

### Example YAML snippet

```yaml

```

### Anything in the logs that might be useful for us?

```txt
Nothing.
```

### Additional information

_No response_

Start at the Tesla Fleet integration's Powerwall Battery Charged sensor and inspect how its value is calculated from the available diagnostics data. Reproduce the reported overnight charge from roughly 20% to 100%, then verify that the sensor reports the corresponding energy charged rather than the incorrect values shown in the issue.

Written by the indexing model from the issue text.