Powershell script to download Tesla Powerwall data to a CSV file

Get-Powerwall-Data.ps1

###############################################################################
# Get a refresh token using something like https://chrome.google.com/webstore/detail/tesla-access-token-genera/kokkedfblmfbngojkeaepekpidghjgag
$REFRESH_TOKEN = 'your.token.here'
# Set as appropriate:
$startDate = [DateTime]::Parse('2023-04-01')
$csvFile = 'C:\temp\my powerwall data.csv'
###############################################################################

# Auth
$token = Invoke-RestMethod -Uri "https://auth.tesla.com/oauth2/v3/token" -Method Post -Body @{
    grant_type = "refresh_token"
    client_id = "ownerapi"
    scope = "openid email offline_access"
    refresh_token = $REFRESH_TOKEN
}

# Get site ids
$products = Invoke-RestMethod -Uri "https://owner-api.teslamotors.com/api/1/products" -Headers @{ Authorization = "Bearer $($token.access_token)" }
#$products.response | ft
[array]$site_ids = $products.response | where { $_.energy_site_id -ne $null } | select -ExpandProperty 'energy_site_id'

"Site IDs: $site_ids"

if (Test-Path $csvFile) {
    $lastTimestamp = (Import-Csv -Path $csvFile | select -Last 1).timestamp
    $startDate = [DateTime]$lastTimestamp
}

# Ensure local time
#  > The format for the end_date parameter value is "yyyy-mm-ddThh:mm:ss-hh:mm". 
#  > Specify your local time zone offset for best clarity. Universal time is 
#  > accepted in the format "yyyy-mm-ddThh:mm:ssZ", but the time is converted 
#  > to your local time zone, which could also change the date."
#  -- https://tesla-api.timdorr.com/energy-products/energy/history#get-api-1-energy_sites-site_id-calendar_history
$startDate = $startDate.ToLocalTime()

"Start date: $startDate"

for ($date = $startDate.Date; $date -le [DateTime]::Now.Date; $date = $date.AddDays(1)){
    "Downloading {0:D}" -F $date

    $end_date = $date.AddDays(1).AddMinutes(-1).ToString("yyyy-MM-ddTHH:mm:ssK")
    # "  $end_date"

    foreach ($site_id in $site_ids) {
        $url = "https://owner-api.teslamotors.com/api/1/energy_sites/$site_id/calendar_history?kind=power&end_date=" + [Uri]::EscapeDataString($end_date)
        #"  $url"
        $data = Invoke-RestMethod -Uri $url -Headers @{ Authorization = "Bearer $($token.access_token)" }

        [array]$records = $data.response.time_series |
            # don't include potentially incomplete records from within last 5 mins
            where { [DateTime]$_.timestamp -lt (Get-Date).AddMinutes(-5) -and [DateTime]$_.timestamp -gt $startDate }

        $records | Export-Csv -Path $csvFile -NoTypeInformation -Append

        "  added $($records.Count) records"
    }
}