I am in the process of purchasing the parts for my dual battery install next month. I have already installed the Shrockworks Dual battery kit.

My setup will be:
Odyssey PC34R-1500 68AH (34Ah usable for 50% SOC)
Redarc BCDC 1225D
Blue Sea 6 Fuse Block (Fridge, extra Blue Sea USB/12v in trunk and power to RTT Anderson plugs on cable - only connected when deployed) Charging ipad/phone. Maybe run a 12v fan or electric blanket.
160w Renorgy Flexible solar on top of RTT
Deployable 100w solar blanket to supplement above when at base camp.
Stich Pro-9100 (Running AUX lights/loads and controlling compressor)
Blue Sea 12v USB/cigarette outlet in trunk.


Reason for Renorgy on the tent is that we hike and climb so the rig is left at trailheads for hours. Did not want a 1000 dollar solar blanket left hanging while away. (Bonus is this is cheapish. Although, I think you can have overheating issues with is stuck to the tent.

Draw while camping
2AH x 12 = 24Ah for Fridge (Poss National Luna 55L)
0.9amps x 2 = 1.8 amps x 4hrs =7.2 amps for camp lights (Baja Designs S2 x 2)
Occasional 12v fan in tent 0.31A x 8hrs = 2.48Amps
TOTAL 33.68

Solar should supply 6-8 Amps for 6hrs (Weather Dependant) = 36 to 48amps
Also, topped up by Redarc when mobile each day.
Once static and present at camp will deploy a supplementary 100-120W blanket (Further 6-8amps)

We mostly travel around but may spend a day or two at one location. We never stay in the same place for much longer than 2-3 days.

Questions
1) Redarc states 6AWG wire for our cable lengths. (Would it be better to use 4AWG?) The Redarc will be mounted directly on top of AUX battery so seems overkill 4AWG. Also, states 40amp MIDI fuse for low resistance (Heat). (These things are huge) Would a 40amp circuit breaker or terminal mount fuse be ok? So, going with 8 AWG as recommended by Redarc. Ordered some metric 40 AMP inline MIDI fuse holders. Much smaller.

2) I want to run 2 pairs of cables to the rear for the fridge and Blue Sea 12v/USB. The fridge will be direct to battery via Anderson connector in rear. Is 10AWG good for the fridge or overkill? Hoping for lowest amp loss/most efficient. Going with 10 AWG for fridge with Anderson. 12 AWG for 12v USB/cigarette.

3) If I use 10AWG for the fridge will it be ok with a 50amp Anderson connector? I know Anderson is made for thicker gauge possibly 6AWG. You can purchase smaller terminal posts for Anderson so 10 AWG is fine.

4) Switch Pro will be mounted on the other side of the engine bay from the AUX battery. What size wire should I use? 2/4AWG? I know it's rated to 125A but would it ever draw that? Going from Blue Sea cable recommendation chart 2AWG would be required. Answered my own question 2 AWG it is.
5) I will be making a mounting bracket for the top of the AUX battery (Mount Redarc BCDC plus 6 fuse Blue Seas block) Will any plastic board be good for this? Looking at HDPE or Acrylic on Amazon 1/2 inch thickness. Never done this before so don't know the tolerances (strength/heat) of these materials. HDPE cutting board ¼ or ½ thick.

6) What gauge and how many wires can you fit down the windshield trunking?

7) Anyone have any ideas for a connection terminal for the solar (Plastic section at the base of the windshield corner) For connecting Anderson (solar). I may just run the cable into the hood then have Anderson connectors under there. Going with weatherproof SAE terminal in the plastic at the corner of the hood. Will utilise SAE to Anderson for solar. This will make adding more solar later easy.

8) Is it ok to earth the AUX battery to the chassis/frame? Or should I run it to the starter battery? What size cable should I use for the earth? Running earth from Redarc to AUX battery terminal, then going to run a length of maybe 2 AWG from AUX neg to Starter Neg. Couldn’t really find anything solid on gauge size. Normally use the same as the positive connecting the batteries. However, in this case, positive feed is via DC-DC so much smaller.


Trying to streamline the cable buying. I will use Marine grade Ancor cables.
10 AWG (To AUX RTT/solar and Fridge)
8 AWG (Redarc install)
2 AWG (Switch Pro)
12 AWG most over 12v loads (Roof lights/ AUX 12v/USB)

I already have a dual ARB compressor mounted to the starter battery. This will be controlled by Switch Pro but the power to remain on the starter. I only use it while the engine is running.
I will install a winch too powered from the starter.

All other accessories will be via Switch Pro (AUX).
6 Fuse Blue Sea (AUX).
Fridge direct to AUX.