Can I run my WFCO output to a REDARC BCDC?

Ok, so you may have two chargers trying to charge at the same time. If your batteries need to be charged, one of those two chargers is going to charge them, or maybe both will share the load. It probably will depend on which one is quicker at ramping up its voltage. There’s at least one member here that uses three or four chargers simultaneously on his battery bank and they share the load. I think the worst that could happen is exactly what you were warned of. The two chargers will sit there at float voltage. I think that’s unlikely, but in that case, turn one of them off. I wouldn’t install a transfer switch unless it was really necessary.

:):)