OutBack Power
Outback FlexMax 80 wiring diagram
80 A MPPT for 12–60 V battery banks. 150 V absolute PV ceiling, 145 V temperature-corrected operating limit, and 64 A maximum array Isc at STC. Configure battery voltage at first startup.
- Compatible systems
- 12 V / 24 V / 36 V / 48 V / 60 V
- Rated output
- 80 A
- PV open-circuit limit
- 150 V
Wiring diagram
How the FlexMax 80 is wired.
Open this example in Crimp to use your own parts and cable lengths. Review the assumptions and installation notes as you adapt the circuit.
Cable sizing for this example
Use the diagram as a starting point for your installation. Replace the example equipment and cable lengths with your own, and check the connections against your exact model's instructions.
3 m one way
12 V system
- Wire
- 25 mm² · 4 AWG
- Example fuse
- 100 A
- Design current
- 80 A
- Voltage drop
- 2.8%
Sized against ABYC E-11. The design current is the unit's rated output. The length is one way; voltage drop includes an equal-length return.
Run-length and manufacturer assumptions
The editable example uses 3.048 m (10 ft) runs unless a shorter run is stated. Metric overviews round these to 3 m. Adapt the parts and lengths to your installation before choosing cable and protection.
Supporting parts
- 6.1 m total of 25 mm² (4 AWG) marine cable
- Terminations for 25 mm² cable, matched to the equipment's screw terminals, leads or studs
- 100 A fuse and holder on the positive run
- Heat-shrink, strain relief and terminal boots sized to the cable
Check stud sizes, fuse type, run length and how warm the space gets against the gear you actually have before you order.
Installation notes
Before you install.
Open a question for model-specific guidance and sources.
Verified against the manufacturer's documentation (rev. 900-0009-01-00 Rev D — January 2020), checked 2026-10-01. Manufacturer documentation →
Which FLEXmax is covered?
This is the FLEXmax 80, not FLEXmax 60 or FLEXmax 100. The downloaded owner's manual applies to firmware 003.003.000 or later. It specifies 80 A continuous output at 40°C and nominal 12/24/36/48/60 V batteries. Above 40°C, output is derated.
The specification table distinguishes 150 V maximum PV Voc from 145 V temperature-corrected operational maximum. Use the coldest expected panel temperature when designing a string. The controller converts a higher PV voltage down to the battery voltage; it does not boost an undersized array voltage.
How do the terminals map?
Crimp's PV + / PV − and BATT + / BATT − map to PV+, PV−, BAT+, and BAT−. The two negative terminals are internally connected. The symbol omits the equipment-ground lug, AUX output, remote-temperature-sensor port, and MATE/HUB communications port.
The wiring-compartment diagram identifies the physical order PV+, PV−, BAT−, BAT+. Each FLEXmax needs its own PV array; two controllers must not share one array by paralleling their PV terminals.
What protection and cable limits apply?
For FM80, printed page 12 specifies OutBack PNL-80-DC breakers for disconnect/overcurrent protection, minimum 4 AWG / 25 mm² battery-output conductors, and a largest array rated at 64 A short-circuit current under STC. The array-current limit is not the 80 A battery output rating.
Use copper rated at least 75°C. Terminals accept up to 2 AWG, and power/ground terminals tighten to 4 N·m. Cable length, installation conditions, and the complete protection system can require a different design from the minimum illustrated installation.
How is it started and configured?
Start with PV and battery breakers open, then energize the battery connection first. Confirm the displayed battery voltage before enabling PV. Factory settings begin at 12 V and the selected nominal voltage is retained after shutdown; moving a used controller to another bank requires checking it again.
Set absorption, float, current limit, and any equalization according to the actual battery manufacturer's instructions. Equalization is a separate high-voltage operation, not routine charging for every chemistry. An optional remote temperature sensor improves compensated charging; a HUB installation needs the sensor arrangement shown in the manual.
Keep the controller ventilated and out of direct sun. Inspect the fan and wiring compartment during maintenance, with all sources isolated.
Fit check
Connect it to the rest of your system.
Describe your setup to draft a system with FlexMax 80 connected. Review the selected parts and cable lengths, then edit the diagram in Crimp.
The model only picks parts and draws the connections. Every wire size and fuse rating still comes from Crimp's own sizing, never from the model.
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Technical reference
Specifications and terminal map.
Check the model, ratings and connection points against your own unit before choosing installation hardware.
Catalog specification
80 A MPPT for 12–60 V battery banks. 150 V absolute PV ceiling, 145 V temperature-corrected operating limit, and 64 A maximum array Isc at STC. Configure battery voltage at first startup.
- Compatible systems
- 12 V / 24 V / 36 V / 48 V / 60 V
- Rated output
- 80 A
- Planning charge current
- 80 A
- PV open-circuit limit
- 150 V
Terminal map
Catalog connection points, current direction and planning limits. Check the manufacturer's pinout and connector ratings before installation.
PV +
positive · input
PV −
negative · input
BATT +
positive · output
BATT −
negative · output
Sources and sizing method
Equipment specifications. Model details, ratings and terminal roles come from the catalog. Check your unit’s label and current manufacturer documentation for its exact revision.
Example sizing. Sized against ABYC E-11. Boats built to UK or EU rules answer to ISO 13297 — check these figures against it before you build. Results use the example current and run length shown above. Set your actual equipment, lengths and installation conditions in Crimp before choosing hardware.
Read how the sizing worksNext step
Plan your installation with FlexMax 80.
Open this example as a new project, or add this component to your existing diagram. Use your equipment and cable lengths to review the sizing.
Start drawing, sizing and checking without an account. Your drawing saves in this browser. See Pricing for the equipment allowance and the one-time export offer available to you.