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OutBack FLEXmax FM100-300VDC 100A 300Vdc MPPT Charge Controller

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Battery Charging Voltages 24/36/48VDC
Controller typeMPPT Charge Controllers
Maximum charging current100 A
Maximum voltage of the solar panels300 V
Dimensions LxWxH23" × 8.8" × 6"
Weight16.0 lbs
ManufacturerOutBack Power Systems
Manufacturer Part #FM100-300VDC-AFCI
Operating Temperatures –13° to 140°F
Warranty5 years manufacture
Delivery Time 5-7 business days

About product

Outback, 100 AFCI-300VDC MPPT Charge Controller, 100A, 300VDC, 12/24/48/60VDC, 100 AFCI

OUTBACK FLEXmax 100 AFCI is an innovative charge controller from OutBack Power Systems. To guarantee reliability, this model had to pass extensive testing, including Highly Accelerated Life Testing (HALT). The proprietary FLEXmax algorithm stays active at all times, boosting your energy production by up to 30% compared to controllers without MPPT. The model comes with integrated arc/ground fault protection and rapid shutdown functionality for advanced safety.

FlEXmax family of charge controllers is manufactured by a company with 15 years of experience in production of fault intolerant equipment. It has a special enclosure to keep the dust and moisture out, making it a good option for outside use. The device records and stores performance data for up to 128 days. Remote programming and monitoring are in the list of features too, providing superior system integration.

Performance, efficiency and versatility – these three words define FLEXmax MPPT Charge Controllers. They charge your batteries faster, maximizing electricity exports to the grid and your return on investment.


  • Networking functionality for remote programming and monitoring
  • Integrated arc/ground fault protection and rapid shutdown
  • Constant Maximum Power Point Tracking (MPPT)
  • PV system output increase of up to 30>%
  • 2-string configuration to minimize BOS
  • Programmable auxiliary control output
  • Unbeatable price to power ratio
  • 128 days of data logging
  • Up to 6kW of charging
  • 5 year warranty

Reviews & Questions

  • Reviews (3)
  • Questions (4)
Works great with my li-ion batteries. Don’t expect any miracles from this unit, but it is a durable workhorse that can be installed outside without worries. I also liked the service and a pickup option, it saved me a lot of time.
08/06/2021 12:39 pm
I did my research before the purchase and you should do the same. Under my circumstances it was the best option, but keep in mind that it requires MATE3, MATE and MATE2 are not supported.
Dilis Calvin
07/21/2021 02:08 pm
Great charge controller, but I wonder why they couldn’t add a small display that you can see in so many other models. If this is an important feature for you, you will have to look through other options, but overall it is an excellent device
Raynard Lewin
07/05/2021 05:07 pm

Leave a review

Can this work with 4 100 ah battleborn battery's And 3000 victron inverter for starters I plan on adding on , eventually Allso does it have remote viewing via smartphone Capabilities?
Robert & Joe
08/15/2021, 17:18
The default settings of the FLEXmax 100 charge controller are for lead-chemistry batteries intended for deep discharge. These include all energy storage for marine, golf-cart, and forklift applications. They also include gel-cell batteries and absorbed glass-mat (AGM) batteries. OutBack Power recommends the use of batteries designed specifically for renewable energy applications. Lithium-based batteries and other advanced battery technologies may require special charging considerations.
can it work with a remote temperature sensor? thx
08/04/2021, 12:12
Yes, a remote temperature sensor is among listed options.
Would it work well as part of a solar array in a mountain hut? What concerns me is height
Bobbi S.
07/25/2021, 16:31
The device is rated for 10,000 ft
Is there a minimum bank size or can I connect it to a single battery?
Janet Leopold
07/16/2021, 07:10
Minimum battery bank size for this controller is 100 Ah.