I understand that the manual specifies that the charger for use would be 10W. My question is, if I use 18W charger, would it damage the DJI OM 4's battery? Second question is, what is the charging limit for the voltage and current?

Hello there Allipapa. Thank you for reaching out and for this inquiry. It would be best to use a recommended charger in charging your DJI OM 4 ( https://www.dji.com/om-4 ) for compatibility and reliability purposes. The DJI OM 4's charging time is at 2.5 hours using a 10W charger. Thank you.