For a 200W solar panel system charging a 12V battery setup this Victron MPPT 100/30 would be an excellent choice.
Victron MPPT 100/30:
Maximum input voltage: 100V
Maximum input current: 30A
Suitable for 12V systems: This model can handle the power output from a 200W solar panel efficiently.
This MPPT charge controller will maximize the energy OUTPUT from your solar panels and ensure optimal charging of your assumed12V battery set up. It also features Bluetooth connectivity for easy monitoring and configuration through the VictronConnect app.