You can install our site as a web app on your iOS device by utilizing the Add to Home Screen feature in Safari. Please see this thread for more details on this.
Note: This feature may not be available in some browsers.
You can't set a time-based price, so you'll need to do the math and figure out the effective price per kWh. If you're charging at 5 kW, then $1.50 per hour is $0.30/kWh.