I'm trying to power some scientific equipment that requires 24VDC/~4A on both mains and battery with solar eventually coming to the mix. In addition, I'm using a Raspberry Pi as the datalogger, which requires 5V/~1A. I'm trying to make sure that I don't start a fire when I do this. As will be evident below, I'm a scientist and not much of an electrical engineer.
This is my current plan: Mains (120V) -> some sort of 120V->24V converter, like this one ->two 12V batteries connected in series (I suppose I just connect the 24V to the + of one and the - of the other)-> split to a 24V->5V converter like this one and to the equipment.
The batteries will be expected to power the unit for ~4hr, so I am aiming for 18Ah batteries. The mains->24V will be expected to be inside, but we will disconnect the batteries et al and expose them to the elements from time to time. The current plan is to house them in a pelican case. That only needs to contain the Pi and everything from the battery onward.
No strong weight restrictions other than "not absurd". Aiming to have low electrical noise on at least part of the circuit- the instrument separates into a heater and instrument part, and the relatively low power instrument part (~500mA) should be pretty clean, but the heater can be pretty noisy. Appearance doesn't matter that much, but something that is clean/"looks safe" would be preferred as it's scientists working with this.
Three main questions here: will I start a fire/electrocute myself? Do I need a charge regulator for this setup or will that only need to come when I move to solar panels? Have I appropriately designed this setup to work?
Finally, one dumb question (although these may all be dumb): what kind of wires/terminals are safe to use to hook this all up? Should I get some kind of fused mains plug to go to the 24V power supply?