Follow these steps to increase the number of days of data shown in JCharts:

1. Click on the 4th button from right on the top toolbar, this will open the timeframe settings window

2. For intraday data: increase the "Intraday Timeframe" to the number of days of data you want to view

For Daily/Weekly: increase the "Historical Timeframe" to the number of years of data you want to view

3. Click OK button to confirm new settings.

4. Click on the 2nd button from left (Save Preferences) on the bottom toolbar to save your new settings

5. Leave JCharts page and come back to JCharts again so new settings are picked up.