Aux Battery Wiring Diagram questions Redarc 1225D and Lifepo4

[mikeywhatwhat]

Hey everyone. I think I am approaching my final design for the aux battery system and was hoping for you experienced folks to look this over and make sure I am not doing anything completely stupid. Any/all criticism welcome. I am trying to keep it simple and spending a bit more money hoping that I only need to do this once in the vans life.

Question I have:
1. Does this diagram seem to make sense? Would this work..?

2. Do I need a relay between the solar/starter battery and the BCDC1225D? See below diagram from Redarc site. I thought the Redarc just needed the solar and starter battery connected and it was smart enough to handle the rest.

3. I assume I need a fuse between the aux battery and the stock fuse box for fuse #3. What size fuse would this need to be?

4. I assume I need a fuse between the solar panel and the Redarc. Would that be a 30amp inline fuse?

Thanks so much!

[Westified]

I believe you can add a positive wire from your shunt to the red wire (positive) from the Redarc that goes to the starting battery (positive). This way you can monitor both batteries with the BMV 712 Victron. Not sure about your relay between the solar and starting battery. The diagram I see in their manual is Lithium specific. You must have an unregulated solar panel. Google their manual and look at figure 2.7.2 on page 11. The Vanagon does not have a smart alternator so you shouldn't need the blue wire to the ignition, unless you installed a smart alternator. Also, I would probably use a little heavier gauge to the solar panel and fuse it.
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1984 Westy Wolfsburg, owned since 1987. FAS 2.0 NA engine conversion in 2022.

[Westified]

This is a diagram of my proposed install of the Redarc BCDC 1225D, Victron battery charger IP65, Victron BMV 712 monitor with shunt. Hopefully it is correct. I am just beginning my install, the parts have arrived.

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1984 Westy Wolfsburg, owned since 1987. FAS 2.0 NA engine conversion in 2022.

[spunky goat]

Westified - Will the Redarc allow current to flow from the Aux battery to the Starter battery when plugged into shore power?

I am considering a similar set-up and have the same Victron IP65 charger as you and wondering if DC-DC chargers allow current to flow from aux to starter battery.

[mikeywhatwhat]

Posting the diagram Westified mentioned here. This doesn't look like the relay is required but also doesn't show the solar panel fused to the Redarc directly. I suppose a fuse could never hurt though, right?

[Westified]

[Westified]

[mikeywhatwhat]

Follow up on the need for a Relay-

Per the Redarc installation guidelines, a relay will NOT be required. It seems the older version of the BCDC1225D would require a relay, so there's some outdated information out there (Youtube install video, old manuals), but I can confirm through Redarc that with the current BCDC1225D you do NOT need a relay if you are using solar and alternate charging.

[puchfinnland]

I assisted Ken with the initial testing of the redarc on the Vanagons, I am currently working on installing a redarc with a 12v relay and an AC battery charger.

I chose this relay-

https://www.amazon.com/gp/product/B08BHNYQYY

its 5 pole, so the input can be switched

my charger is a dual output

one leg goes to the start battery, the other to this relay

IGN off the second leg is in the N/C position-which feeds the redarc

IGN on, the relay switched from AC battery charger to start battey input,

this isolates both legs of the AC charger to work independently

the relay is powered on to connect and isolate the ac charger.

its idiot proof
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ABYC marine master technician , EX European auto technician, new business- EASTCOASTWEST , custom work on campers, only systems, no mechanical

[Arne@kleinersyncro]

[howler9]

[Reckless Amateur]

I spent all day wrestling with the Redarc Lifepo2 install. Don't get me started with all the stupid mistakes I made.

I have a lingering question, though. Two actually:

1. What is the thing shown on the Redarc diagram that says low voltage disconnect?

2. More important, if I'm simply trying to connect my Truck Fridge to the Lifepo4, I just run the positive wire (fused) from the fridge to the positive terminal on the battery and the black wire to ground, correct?

Sorry for the stupid questions. Had a long day, a big trip coming up, it's been awhile since I messed with my wiring, my skills are basic, and I'm tired. Time for a beer, but hoping somebody can help me out. Thanks, folks.

David
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91 Bostig-powered Westy (automatic)
Philadelphia, PA

[Westified]