Connecting dual battery system to shore power question
 

Hey there guys. So I'm designing a dual battery system using the Redarc BCDC1225D. My plan is to have a portable solar panel that I can use for longer trips to charge the batteries in addition to the alternator. I'm clear about how to set up this part of the system.

What I don't know is, how and where do I integrate a connection for shore power into this setup? If I'm at a campsite with power I'd like to be able to use that for charging and powering accessories when possible.

Any suggestions? My setup will look something like this:

https://imgur.com/fRiGC6V

Any suggestions from the electrically inclined would be greatly appreciated.

Ben

Use a completely separate AC to DC charger / battery tender and connect it directly to the battery as you would regularly. Noco makes a multi-channel unit as well so charge both starter and dual independent of each other.

It bypasses the Redarc setup because it has nothing to do with it.

NOCO - On-Board Battery Chargers

A ha. I see. The noco boxes are just like my Ctek one. That makes sense.

This is pretty handy looking too: NOCO - AC Port Plug - GCP1

If you havent already bought the charge controller, some charge controllers have 120V input

Do you have a example?

Most of those applications that use a "charger/inverter" like used in RVs and motor homes were usually much larger in size.

Response from Redarc for anyone who's interested...
 

Quote:

"If you only want to charge the auxiliary battery just wire it directly to the auxiliary battery terminals. If you want to charge BOTH batteries from mains power, hook the AC charger to the starting battery terminals. Once the starting battery reaches over 13.2v, the BCDC will turn on and send power to the auxiliary battery also. "


b

Their answer is essentially what I said… It’s still an AC to DC battery charger.

Yes, that will work. That said there are some conditions where that might not work as well as you might want it to which is why I recommended a dual channel charger. You could of course just use a single as well.

If you are charging from AC at a rate which is lower than the rate of the Redarc to the 2nd battery, you will eventually deplete the starter and hit the low disconnect voltage. Ultimately you are going to be cycling in and out of charge. If you have load on the 2nd battery, like a fridge, it wont be supported by the AC charger until the starter is satisfied. If you have a load on the starter, light factory loads, it may never be satisfied depending on your AC charger.

The solution is easy… just buy a big enough single battery charger which can support the Redarc charge current to prevent cycling. Or buy a dual channel charger.

Thanks for this thorough answer!