I'm working on a project that has a high availability requirement. As such, I must maintain a power supply output of 12vdc ~1a (ideally 13.5vdc ~35a). The 1a option will sustain the core equipment, whereas 35a will maintain everything
Currently, we have the ability to use an AC to DC converter, OR a DC supply (Battery/Alternator/etc.). In order to meet the new requirement, I need the ability to transfer from an AC input source to a DC input source, and back.
I've included a simple diagram below showing what I need. Both the 120v AC and 12v DC inputs will be connected at the same time, but with the default power coming from 120v AC. In the event either is unplugged, it will fail-over to the other. If AC is ever connected, it will run off of AC.
In short, an off the shelf battery backup would function just fine for this - however I would need to find one that offers high amperage DC outputs vs the AC outputs.