[Build Walkthrough] Custom Dual Battery Setup - REDARC BCDC alpha 50r

[mvilla]

Great info, thank you. Not too expensive. I will message you for 3d files. What gauge wiring are you using? I'm not too good with electrical but this seems pretty straight forward.

I used everything from 1/0 AWG for the ground connection, 4 AWG for the longer runs to the starter battery, 6 AWG for the battery connectors, and 12-16 AWG for wiring the loads. Lmk when you’re ready for the files and if you need help with anything.

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[tny]

I'm actually in the process of buying parts for a similar build, with a 100AH lifepo4 battery enclosed in a MOLLE system and a Redarc Alpha 50R. Just curious, can you link the anderson connector you pre-wired for future solar? I am getting a solar panel that has MC4 Connectors, besides the wiring kit I am also getting from Redarc, I think the solar connection is the one part I am not sure on. Also I need to get some ground cables, but figured while I'm filling up my Redarc cart I'd grab the correct cable from them if I need to. Sick build by the way, inspiring me to finish this project!

 

[mvilla]

I'm actually in the process of buying parts for a similar build, with a 100AH lifepo4 battery enclosed in a MOLLE system and a Redarc Alpha 50R. Just curious, can you link the anderson connector you pre-wired for future solar? I am getting a solar panel that has MC4 Connectors, besides the wiring kit I am also getting from Redarc, I think the solar connection is the one part I am not sure on. Also I need to get some ground cables, but figured while I'm filling up my Redarc cart I'd grab the correct cable from them if I need to. Sick build by the way, inspiring me to finish this project!

Nice I would like to see some photos when you’re done!

I used this Anderson connector and panel mount from powerwerx:

https://powerwerx.com/anderson-sb-connectors-sb50-50amp

https://powerwerx.com/panelpodsb-anderson-sb50-mounting-pod

 

[mvilla]

To manage temperatures I added a W1209 controller and a blower fan to the enclosure.

• Blower Fan: 120mm x 120mm radial blower rated at 31.6 CFM
• Controller: W1209 digital thermostat wired to trigger the fan

Everything fits nice and snug. I have them mounted with Velcro to the lid of the enclosure for now. I will reassess later on if I need to hard mount them, but for now this is ok.

The W1209 thermostat can be programmed to activate power to the fan when the temperature reaches a certain threshold. It’s set to kick on at 110 degrees and turn off at 100.

I’ll post some performance results after a few long drives.

 

[Destination Bigfoot Bronc]

To manage temperatures I added a W1209 controller and a blower fan to the enclosure.

• Blower Fan: 120mm x 120mm radial blower rated at 31.6 CFM
• Controller: W1209 digital thermostat wired to trigger the fan

Everything fits nice and snug. I have them mounted with Velcro to the lid of the enclosure for now. I will reassess later on if I need to hard mount them, but for now this is ok.

The W1209 thermostat can be programmed to activate power to the fan when the temperature reaches a certain threshold. It’s set to kick on at 110 degrees and turn off at 100.

I’ll post some performance results after a few long drives.

Do you have the part numbers for the anderson and connector terminals that connect on the battery

 

[mvilla]

Do you have the part numbers for the anderson and connector terminals that connect on the battery

The Anderson connectors are SB50 connectors.

https://powerwerx.com/anderson-sb-connectors-sb50-50amp

I used 8 AWG for the wires connecting the batteries and the only spade connectors I could find that fit were these ones from Amazon:

https://a.co/d/36MWw14

(The heat shrink will say 10 AWG but the connector is sized correctly for 8 AWG)

 

[Direvarg]

After comparing a few popular options—like the American Adventure Lab rear storage battery tray—I opted to build a fully custom dual battery setup in my Bronco using the DV8 expanded cargo storage box. The AAL tray was solid, but I went custom for two key reasons:

1. I can fit 5x 20Ah batteries (vs 4 with the AAL), giving me 100Ah total.
2. My design allows the enclosure to fully close, which the AAL solution cannot do when loaded.

The result is a compact, serviceable 12V system that powers all my gear cleanly and reliably—and it’s future-ready for solar and cooling upgrades.

Build Goals:

• Fully self-contained auxiliary power with clean install
• Enough juice to run fridge, lighting, device charging, and Starlink
• Modular for future upgrades (solar, cooling)
• Easy access for troubleshooting and expansion

System Overview:

• Battery Bank: 5x Amped Outdoors 20Ah LiFePO₄ (wired in parallel = 100Ah)
• Charger: Redarc BCDC Alpha 50R, mounted on the driver-side rear window molle panel
• Mounting: Custom 3D-printed battery trays with roller cam straps, secured in the DV8 expanded cargo compartment
• Power Distribution:
  • Blue Sea fuse block mounted on the passenger-side rear window molle panel for loads
  • Custom 3D-printed fuse block with copper bus bar located inside the enclosure for internal power routing

Connected Loads:

• ICECO APL55 dual-zone fridge
• Mabett rear cargo light
• 4x USB-C outlets
• Baja Designs dome lights (1 amber, 1 red)
• Starlink Mini
• Blue Sea OLED temperature monitor

Expandability:

• Cooling: Space is tight and the enclosure gets hot. I’m planning to add a heat-activated blower fan to keep things cool
• Solar: Pre-wired with an Anderson input for solar charging via the Redarc Alpha’s solar input
• Inverter: The system is ready to accept an inverter if I need it, but so far the in cabin inverter has been fine

Happy to answer questions or help anyone working on a similar project. Feel free to ask about any of the components, 3D-printed parts, or design choices.



****Update****
To manage temperatures I added a W1209 controller and a blower fan to the enclosure.

• Blower Fan: 120mm x 120mm radial blower rated at 31.6 CFM
• Controller: W1209 digital thermostat wired to trigger the fan

Everything fits nice and snug. I have them mounted with Velcro to the lid of the enclosure for now. I will reassess later on if I need to hard mount them, but for now this is ok.

The W1209 thermostat can be programmed to activate power to the fan when the temperature reaches a certain threshold. It’s set to kick on at 110 degrees and turn off at 100.

I’ll post some performance results after a few long drives.

You sir are amazing. Doing the AAL install of this and your post clears up quite a few questions I had

 

[BigMeatsBronco]

What issues, if any, with the OEM factory Battery monitor system? Did you change the alternator charging % in forescan?

 

[mvilla]

You sir are amazing. Doing the AAL install of this and your post clears up quite a few questions I had

Glad I could help!

What issues, if any, with the OEM factory Battery monitor system? Did you change the alternator charging % in forescan?

No issues with the factory system. I keep an eye on the battery voltage while driving and it hasn’t changed at all since installing. If there’s another way to monitor that I’m not aware of, please let me know. No changes in forscan

 

[BigMeatsBronco]

Glad I could help!



No issues with the factory system. I keep an eye on the battery voltage while driving and it hasn’t changed at all since installing. If there’s another way to monitor that I’m not aware of, please let me know. No changes in forscan

the Broncos are set from factory to charge to 80%, some of us have changed this in forscan...mine is at 90%... thanks looks like a nice setup. are these lithium batteries?

 

[Demon4x4]

• Battery Bank: 5x Amped Outdoors 20Ah LiFePO₄ (wired in parallel = 100Ah)

The Amped Outdoors 30Ah Lithium Battery (LiFePO4) seems to come in a tall version - same foot print as the ones you used, but 2.24" taller. Wonder if those would fit in here with smaller conenctors than the Anderson ones you used, to squeeze 150ah in there.

 

[Direvarg]

The Amped Outdoors 30Ah Lithium Battery (LiFePO4) seems to come in a tall version - same foot print as the ones you used, but 2.24" taller. Wonder if those would fit in here with smaller conenctors than the Anderson ones you used, to squeeze 150ah in there.

I’m not sure they would. The photo below is with the trunk floor plates removed and showing the black support brackets that the floor bolts to. They’re only about an inch and a half higher than the batteries

 

[Mean Green]

I can’t find any leaks, but I always seem to have moisture in that well. Do you have that issue? If so, has it caused any issues for you?

 

[JediMcMuffin]

This is a very cool build, a great use of some compact space.

My own setup gives ~950Wh of usable energy using an EcoFlow Delta 2 on a shelf above the fridge. The Delta 2 is about the same size as the pictured Dometic jug.

I have 2 x 110W renogy solar panels on the Trailrax on the roof, and the Ecoflow DC to DC charger coming from the alternator mounted on a side molle panel. I also have another 298Wh of battery built-in to the Ecoflow Glacier. The Delta 2 provides me 12V, 110V up to 1800 watts, and USB outputs pretty conveniently.

So far my experience is that this is a very nice sweet spot of usable power. The solar panels on my last trip fully negated the draw of my fridge and starlink dish and I was able to use the Delta 2 to recharge everything else I needed and really only needed to start my engine for the DC to DC to kick in because we ended up using the inverter to power a televsion to watch football all day while camping at 11,000 feet.

Nerding out on this stuff is fun , Cheers.

 

[Direvarg]

I can’t find any leaks, but I always seem to have moisture in that well. Do you have that issue? If so, has it caused any issues for you?

I haven’t but I noticed two things, one is the holes that the stock floor bolts to are pass through so if you unscrew the stock floor, water can get inside from underneath (maybe try tightening those screws?) I ended up using plastic body plugs that fit and plugged the holes. The other is there is a drain in that area you can make sure that plug is fully sealed

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