NOTE: As an Amazon Associate, I earn from qualifying purchases.  Learn More.

flexmax 80 charge controller

Outback Flexmax FM80 Solar Charge Controller Review

outback flexmax 80 price

Overview of the product 

The Outback Power MPPT 80 is undoubtedly one of the best solar charge controllers out there. Its design is simple but carries some interesting digital touches that improve its performance. It is the number one choice of people who expect durability, superior performance, and efficiency from charge controllers. Thus, it can be the perfect choice for your advanced power system. 

With this impressive device, you can adjust your system's voltage, track its current status, and revisit and read about 128 days worth of data. It is equipped with Outback’s Maximum Power Point Tracking (MPPT) software algorithm, which is continuous and active. MPPT controllers effectively increase photovoltaic array power yield by 30%. With the aid of MPPT, the unit can determine the best voltage and current magnitude to optimize the power it sends to the batteries.

If you are new to solar charge controllers and have no idea about them, see our guide to solar charge controllers

outback flexmax 80 charge controller

Product Specifications

Quick Summary


Solar Charge Controller 


Maximum Output Current:

80 Amp. at 104°F (40°C)

Nominal Battery Voltage:

12, 24, 36, 48, or 60 DC.

Standard Power Consumption: 

Less than 1W typical

Maximum PV array power (NEC Recommended):

12 VDC systems: 1000 Watts

24 VDC systems: 2000 Watts

48 VDC systems: 4000 Watts

60 VDC systems: 5000 Watts

Peak Efficiency:


Power Consumption Efficiency: 

97.5% at 80 ADC

Charging Regulation:

Bulk, absorption, float, silent, and equalization

Battery temperature Compensation:

Automatic with optional RTS installed

Remote Display and controller:

optional Mate, Mate 2, or Mate 3

Environment Rating:

Indoor Type 1


ETI listed to UL1741, CSA C22.2 No. 107.1

Unique Features

The Outback Flexmax FM80 is an incredibly well-designed unit, but what about it sets it apart from the plethora of charge controllers in the market? Well, there are certain unique features this device carries that sets it apart from others and have earned it a good reputation in the market. These include:

Data Logging:

It is surely one of the most interesting features of this controller. With this feature, the device can keep up to 128 days' worth of operational data in its memory and allow you to read it.  

User Interface:

One of the most liked features of this device is the convenient user interface and simple design. The device is designed to deliver the essentials of a charge controller while having a user-friendly interface.


Outback Flexmax FM80 is one of the most well-made and durable units out there. It comes with an impressive 5-year warranty, which you can upgrade to a 10-year warranty if you want. 

Thermal Management:

Overheating is a common problem most solar charge controllers face. To counter that, this unit has a thermal management feature. The built-in fan actively cools the system and keeps temperature regulated. 

Pros and Cons of the Outback Flexmax FM80 Solar Charge Controller

Still on the fence about whether or not the Outback Flexmax FM80 is the right one for? Perhaps, looking at the pros and cons will help you decide if it is the one for you. 


  • It carries a data-logging feature that keeps about 128 days' worth of data in its memory and allows you to read it.
  • The Advanced Continuous MPPT increases the PV array output by a maximum of 30%
  • Features a smart, backlit 80-character display that shows the complete current operational status
  • Incredibly well-made, innovative, and secure
  • This is a highly versatile device that is programmable to adapt to the different battery changes.


  • There is a lack of clear instructions for setting up the device, which may lead to confusion.
  • The design is incredibly basic and might not be the best controller for all those who are used to having more advanced controller options.
flexmax 80 charge controller

The Display Panel

The Outback FM80 has backlit 80-character (4 lines) built-in display that shows the system's operational status. The display has a 3.1-inch or 8 cm wide LCD screen.

It is easy to view even in low-lighting conditions due to being backlit. Plus, the display has data logging features that store data for the last 128 days so you can revisit and read the amps, amp-hours, peak watts, solar array voltage, watt-hours, and time in float. You can also see the maximum and minimum battery voltage, absorb time, kWh of production, and accumulated amp-hours.

The menu is available in two languages, Spanish and English. Navigating through the menu is pretty easy due to the intuitive user interface. The display provides available information clearly, so you can easily track the system's performance without doing any guesswork. 

How it compares with the FLEXmax 60 Controller 

The FLEXmax 60 is an incredibly well-designed controller; however, when compared to the FM80, it may be too basic or primitive. The FM60 lacks some exciting features that are present in the FM80. Here is a breakdown of how the two units compare:


Data logging: The FM80 allows you to keep track of 128-days of operational data. This feature is absent in the FM60.

Voltage step-down capability: The FM60 cannot down-convert from any acceptable array voltage, whereas FM80 can. For example, FM80 can convert from a 72 VDC array to a 24 VDC battery. 

Programmable Auxiliary Control Output: FM80 comes with a feature that allows programming a 12 VDC output signal for different control applications, whereas FM60 doesn’t. 


They have several similar, basic features such as the same maximum output current, nominal battery voltages, warranty, certifications, status display, etc. 

Where to Buy the Outback Power FLEXmax FM80 MPPT Solar Charge Controller?

You can buy the Outback Power FLEXmax FM80 MPPT Solar Charge Controller here. However, if this isn’t exactly what you are looking for, check out our review of the best solar charge controllers

About the Author David Roberts

I'm a Mechanical Engineer who's obsessed with solar energy and sustainable living.

follow me on:

Let's Stay In Touch!

Subscribe now to receive more articles, offers and tips like this!

Leave a Comment: