ACOPower Midas 40 Amp MPPT Solar Charge Controller

The ACOPower Midas 40A MPPT Solar Charge Controller Gets More Charge From Your Panels in 12V and 24V Off-Grid Systems

The ACOPower Midas 40A MPPT Solar Charge Controller is a 40 amp maximum power point tracking controller for 12 volt and 24 volt battery banks. It tracks the maximum power point of your solar array with up to 99.5% tracking efficiency, then converts the panel voltage down to the right charging voltage for your battery with a peak conversion efficiency of 98.6%. ACOPower rates it for up to 520 watts of charging power on a 12V system and 1040 watts on a 24V system.

A 100 volt PV input limit lets you wire panels in series, which keeps array current and wire size down on longer runs from the roof or ground mount to the battery. The controller works with sealed, gel, flooded and user-defined lead-acid settings, plus LiFePO4 and NCM lithium profiles.

ACOPower Midas 40A MPPT Solar Charge Controller Features

Up to 99.5% MPPT Tracking Efficiency

An MPPT controller adjusts its input to the voltage where your panels produce the most power. ACOPower says this can raise energy use by 20% to 30% compared with PWM charging. The Midas 40A also recognizes multiple power peaks, which helps when part of an array is shaded.

12V and 24V Auto Detection

With lead-acid batteries the controller identifies a 12V or 24V system automatically. With lithium batteries the system voltage has to be set manually, because lithium voltage cannot be identified automatically. The working battery voltage range is 8 to 32 volts.

Lead-Acid and Lithium Charging Profiles

Built-in profiles cover sealed (the default), gel and flooded lead-acid batteries, plus LiFePO4 and Li(NiCoMn)O2 lithium. A user mode allows custom voltage settings through the MT-50 or ACOPower's PC software. Temperature compensation defaults to -3mV per °C per 2V cell for lead-acid and is fixed at zero for lithium.

40 Amp Load Output With Timer Modes

The load terminals can switch up to 40 amps of DC loads. Load modes include manual control, light on and off (dusk to dawn), light on plus timer, and real-time clock control, which suits lighting, pumps and monitoring equipment.

Built to Protect Itself and Your Battery

Electronic protection covers PV short circuit, PV and battery reverse polarity, battery over-voltage and over-discharge, and load overload. If the internal temperature reaches 81°C the controller steps down its charging power, and it stops charging above 85°C until it cools.

RS485 Communication

An isolated RS485 port (RJ45, 5V and 200mA) uses the Modbus protocol. It connects the MT-50 remote meter, a USB to RS485 cable for PC monitoring, or an RS485 Bluetooth adapter for app monitoring.

Real-World Applications

RV and van solar. Charge a 12V house battery from one to several roof panels.

Cabins and sheds. Run lights and small DC loads from a 12V or 24V battery bank.

Remote monitoring and lighting. Use the timer and dusk-to-dawn modes for lights, cameras or gate openers.

Boats and trailers. Keep batteries topped up between trips.

How It Compares to Common Alternatives

Versus PWM controllers. A PWM controller such as ACOPower's ProteusX 20A connects the panel almost directly to the battery, so panel voltage above battery voltage is wasted. MPPT converts that extra voltage into charging current, which matters most in cold weather and with higher voltage panels wired in series.

Versus the Midas 30A. The Midas 30A uses the same platform and features. The 30A version is rated for less charging current and smaller arrays. Choose the 40A when your array is up to about 520W at 12V or 1040W at 24V.

With or without the MT-50. The controller has its own LCD and buttons. ACOPower also offers this controller bundled with the MT-50 remote meter if you want to mount the display away from the controller.

Versus the 50A and 60A MPPT controllers. ACOPower's 50A and 60A models add 36V and 48V support and a 150V PV input for larger systems.

Is This Charge Controller the Right Fit

• Battery bank. 12V or 24V lead-acid or lithium.
• Solar array. Open circuit voltage below 100V at the coldest expected temperature (92V at 25°C). ACOPower recommends keeping array power within 1.5 times the rated charging power.
• Wiring. Recommended cable is 6 AWG (16 mm²).
• Mounting. Indoor or sheltered location. The enclosure is rated IP33.

This may be a good fit if

• You want MPPT efficiency at a modest price
• You have a 12V or 24V system with panels wired in series
• You need a timer or dusk-to-dawn load output
• You want room to add an MT-50 or PC monitoring later

Common Questions

How Many Panels Can the Midas 40A Handle?

ACOPower rates it for 520W at 12V and 1040W at 24V. With typical 100W 12V panels that is about 5 panels on a 12V battery or 10 on a 24V battery, as long as the series open circuit voltage stays below the 100V limit at the coldest temperature.

Does It Work With Lithium Batteries?

Yes. It has LiFePO4 and Li(NiCoMn)O2 profiles plus a user mode. Set the system voltage manually when using lithium, since it cannot be detected automatically.

What Order Should I Connect It In?

ACOPower says to connect the battery first, then the load, and the solar panels last.

Can I Monitor It From My Phone?

Yes, with ACOPower's optional RS485 to Bluetooth adapter. A USB to RS485 cable is also available for PC monitoring.

What's Included

• 1 x ACOPower Midas 40A MPPT Solar Charge Controller
• 1 x User Manual

Efficient 40 Amp MPPT Charging for Small and Mid-Size Systems

The ACOPower Midas 40A MPPT Solar Charge Controller brings MPPT efficiency, lithium-ready charging profiles and flexible load control to 12V and 24V solar systems. At Outbound Power, we help customers match controllers to their panels and batteries. If you have questions, our team is happy to help.