Outback Flexmax 80 MPPT Solar Charge Controller

$599.00 List price $849.00
  Customer Reviews (6)

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Item code Brand name Model number Amps
OUTFW-FLEXMAX80 Outback FM80-150VDC 80A

Outback Power SystemsOutback Power Systems
FLEXmax 80
MPPT Charge Controller


Outback Flexmax 80

The FLEXmax 80 is the latest innovation in Maximum Power Point Tracking (MPPT) charge controllers from OutBack Power Systems. The FLEXmax 80’s innovative MPPT algorithm is both continuous and active, increasing your renewable energy yield up to 30%. Thanks to enhanced cooling, the FLEXmax 80 can operate at its full 80 amp maximum current rating in ambient temperatures as high as 104°F (40°C).

Included in the FLEXmax 80 are all of the features first developed by OutBack Power in the revolutionary MX60, such as support for a wide range of nominal battery voltages and the ability to step-down a high voltage solar array to recharge a low voltage battery. A built-in backlit display shows status information at the touch of a button. Enhanced network communications allow the FLEXmax 80 to be remotely programmed via the optional MATE system display and controller.

The new FLEXmax 80 is the only choice when you demand a high performance, efficient and customizable charge controller for your advanced power system.


  • Increases PV Array Output by up to 30%
  • Advanced Continuous Maximum Power Point Tracking Algorithm
  • Full Output Capacity in Ambient Temperatures up to 104°F (40°C)
  • Battery Voltages from 12 VDC to 60 VDC
  • Automatic Battery Voltage Detection at Start Up
  • Fully OutBack Network Integrated and Programmable
  • Programmable Auxiliary Control Output
  • Negative or Positive Ground System Capable
  • Built-in 128 days of Data Logging


FLEXmax™ 80 Specifications*
Nominal Battery Voltages
12, 24, 36, 48, or 60 VDC (Single model - selectable via field programming at start-up)
Maximum Output Current
80 amps @ 104° F (40°C) with adjustable current limit
Maximum Solar Array STC Nameplate
12 VDC systems 1250 Watts / 24 VDC systems 2500 Watts / 48 VDC systems 5000 Watts / 60 VDC Systems 7500 Watts
NEC Recommended Solar Array STC Nameplate
12 VDC systems 1000 Watts / 24 VDC systems 2000 Watts / 48 VDC systems 4000 Watts / 60 VDC Systems 5000 Watts
PV Open Circuit Voltage (VOC)
150 VDC absolute maximum coldest conditions / 145 VDC start-up and operating maximum
Standby Power Consumption
Less than 1 Watt typical
Power Conversion Efficiency
97.5% @ 80 Amps in a 48 VDC System - Typical
Charging Regulation
Five Stages: Bulk, Absorption, Float, Silent and Equalization
Voltage Regulation Set points
10 to 80 VDC user adjustable with password protection
Equalization Charging Programmable Voltage Setpoint and Duration - Automatic Termination when completed
Battery Temperature Compensation
Automatic with optional RTS installed / 5.0 mV per °C per 2V battery cell
Voltage Step-Down Capability
Can charge a lower voltage battery from a higher voltage PV array - Max 150 VDC input
Programmable Auxilary Control Output
12 VDC output signal which can be programmed for different control applications (Maximum of 0.2 amps DC)
Status Display
3.1" (8 cm) backlit LCD screen - 4 lines with 80 alphanumeric characters total
Remote Display and Controller

Optional Mate or Mate2 with RS232 Serial Communications Port

Network Cabeling
Proprietary network system using RJ 45 Modular Connectors with CAT 5e Cable (8 wires)
Data Logging
Last 128 days of Operation - Amp Hours, Watt Hours, Time in Float , Peak Watts, Amps, Solar Array Voltage, Max Battery Voltage Min Battery Voltage and Absorb for each day along with total Accumulated Amp Hours, and kW Hours of production
Hydro Turbine Applications
Consult factory for approved Turbines
Positive Ground Applications
Requires two Pole Breakers for switching both positive and Negative Conductors on both Solar Array and Battery Connections (HUB-4 and HUB-10 can not be used for use in positive ground applications)
Operating Temperature Range Minimum -40° to maximum 60° C (Power capacity of the controller is automatically derated when operated above 40° C)
Environmental Rating Indoor Type 1
Physical Specifications
Conduit Knockouts One 1" (35mm)on the back; One1" (35mm) on the left side; Two 1" (35mm) on the bottom
Warranty Standard 5 year
Weight - Unit, 12.20 lbs (5.56 kg)
  - Shipping, 15.75 lbs (7.10 kg)
Dimensions - Unit 16.25" x 5.75" x 4" (41.3 x 14 x 10 cm) - (H x W x D)
  - Shipping 21" x 10.5" x 9.75" (53 x 27 x 25 cm)
Options Remote Temperature Sensor (RTS), HUB 4, HUB 10, MATE, MATE 2
Menu Languages English & Spanish

Use appropriate wire size in accordance with NEC.
* Specifications subject to change without notice.


Outback Power Systems

Here are some tips from the altE staff

  • The FlexMax 80 offers both English and Spanish menu languages. The Spanish interface is accessed through the main menu upon unit startup.

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Serious issues

I have had one of these units for almost two years. Soon after I installed it I was noticing that some mornings it just didnt track right. It would end up putting little load on the panels even though there was reasonable energy available.

On the Outback forums they first denied that ...
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solid units

Two of these came with my Outback Flexpower system. It's only been 2 months but they're performing well. Have had a couple brief power spikes of 4200 watts from the array into one of them, handled it fine (4000W max. recommended).

Also make sure when you size your strings you s...
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3 Years, No Problems!!

I have had the Flexmax 80 for over 3 years now and not a single issue. I have a 24v battery bank and 1100 watts of solar in an off grid house. One great advantage is that it has the option to have the backlight on the display to stay on. The controller is in a dark storage room so it makes it ...
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FLexMax 80 Flexibality

I own 2 of These Units So Far So Good ! They Are Tough Units I would Recommend These Too Anyone OutBack Has Incredible Service And Support and These Units Are Field Serviceable If They Need Work On Them ! The Best Money Can Buy Kenneth Viar

Worth every penny

I just recently installed one of these units at my off grid cabin in Eastern Washington. I had previously been using a Xantrex C40 and after two years my batteries were toast - as I was unaware of the downfalls of a PWM controller and it had allowed them to steadily drop to a useless voltage. Ove...
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