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PSU's designed to run on 12V DC input (aka RV or off-grid power systems)?

EGardner

2 months ago

Does anyone know of any power supplies designed to run on 12V DC input?

Background

Most RVs and off-grid power systems revolve around a 12 V DC system, due to the nature of the typical battery components. These systems typically power everything in the system with the DC system, and can include an inverter to provide normal 120V AC power to specific plug-ins. Likewise, in many areas people prefer to avoid having any 120V AC wired into the house as that brings with it a lot of electrical code requirements that don't exist for DC wiring. And electrical code requirements generally means getting expensive specialists out into rural areas.

Given that it seems inefficient to convert 12 V DC power into AC just so that it can be fed into a PSU that will convert it back into a variety of DC voltages (including 12V), it seems like a fairly significant amount of efficiency could be gained by having a PSU designed to run on 12V DC that can directly convert the power into the appropriate voltages.

On the same lines, skipping the AC back to DC step inside the PSU, I would think could reduce the amount of heat being produced inside the PSU.

So, the gist of all that is: Does anyone know of any PSUs designed to run on 12V DC power systems?

Ideally, I am looking for a 550W PSU at 80+ Gold or better efficiencies, but given that I haven't found any yet, I will consider anything.

Comments

  • 2 months ago
  • 2 points

Your best bet would probably be a pico or nanoATX power supply, but even then they use an AC-DC adapter, like a laptop.

https://www.lazer3d.com/dc-dc-power-supply-guide/ https://www.hdplex.com/hdplex-400w-hi-fi-dc-atx-power-supply-16v-24v-wide-range-voltage-input.html

You might get more knowledgeable responses about this style of PSU on another forum.

https://smallformfactor.net/

  • 2 months ago
  • 1 point

Thanks! I appreciate the new directions to take a look at.

  • 2 months ago
  • 2 points

Given that it seems inefficient to convert 12 V DC power into AC just so that it can be fed into a PSU that will convert it back into a variety of DC voltages (including 12V), it seems like a fairly significant amount of efficiency could be gained by having a PSU designed to run on 12V DC that can directly convert the power into the appropriate voltages.

I know it seems inefficient, but the problem with running directly off of 12VDC is that you can't easily regulate the voltage. It's not terribly hard to drop a DC voltage, but it's the devil to raise it effectively (especially when there's no higher voltage source to draw from). In general, the simplest and most efficient way is ... to turn it into AC!

Now, if the power source were something like 15V DC with a guarantee to not sag below 12V regardless of load, that might be a different story, but that's not what you typically have with RV and similar sources.

  • 2 months ago
  • 1 point

Thanks for the explanation. I'm not sure about 15V DC, but it is a pretty straight forward process to increase the base voltage of the system to 24 V, although I'm not sure how that will impact the solar panels and charging, since the ones I've been looking at are about 18V. Looks like I will need to do some more research on this.

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