Can I use direct 12V batteries to power PCs/cameras/Raspberries instead of converting to AC and then back to DC?

Question

I'm planning on building a new house. One of the things I want to do is to set a special powerline for all high priority electronics like cameras, PCs, Raspberries (for domotic system.)

My idea is to have a power backup system, sort of a Tesla powerwall, but what I was thinking is, what happens if I just get the 12V I need for all those appliances directly from the baterry bank? Instead of converting it with the inverter then back to DC with each individual transformer. It seems like a waste of energy in those processes.

Would it be possible to do it this way? Do I need something to rectify the voltage of the batteries?

This is an example of the connection I want to do:

For Raspberries and cameras I imagine is quite possible to do it, but can I power computers directly in this way? Remove the power supply and connect them directly to the 12V powerline.

Answer 1

Conversion wastes energy. So does transferring energy at low voltages due to the high currents involved.

You just need to calculate if your system can do this, and how thick wires you need to provide the required current with low enough losses. So in general, low voltage transfer can cost more in the wiring than high voltage transfer with conversion done at point of load.

Also standard computers can't directly work with only 12V input, they need a power supply to convert input to multiple different voltages that are needed for operation, so you can't just remove the power supply and run it with 12V.

Answer 2

can I power computers directly in this way? Remove the power supply and connect them directly to the 12V powerline.

If they can work directly off 12 V then yes (I have done this with a laptop by replacing the cells in an 11.1 V battery with a 12 VDC connection) but most desktop computers have a power supply that produces multiple voltages. Boards are available that plug into the motherboard and produce these voltages from a 12 VDC supply.

Most laptop computers run from ~19 VDC. For these you may be able to use a suitably rated voltage booster. However some laptops communicate with the power supply and may not work with a bare DC connection. For these you would have to use an inverter to power them via their mains adapter.