40AH Solarpex Solar Charger Controller features:

• Amperage: Likely 40A, suitable for solar panel systems up to around 520 watts (assuming 13 volts).
• Voltage: Probably 12V or 24V automatic detection for working with different battery banks.
• PWM vs. MPPT: It's unclear if it uses Pulse Width Modulation (PWM) or Maximum Power Point Tracking (MPPT) technology for charging. PWM is simpler but less efficient, while MPPT is more efficient but complex.
• Basic protections: Overload, short circuit, and reverse polarity protection are common features.
• Display: Might have LED or LCD display for monitoring charging status.