12v electronics project gut check

[bradjones1]

Curious the hive-mind's thoughts on a 12v electrical project I'm considering.


New owner of a 377RLBH; no kids here so I am working on setting up the bunkhouse as an office space. I have an LED computer monitor and laptop that both run on 19.5v that I would like to be able to wire into the 12v system so as to maximize my future options for sites without electricity (the unit came with the 190W panel and GoPower controller, so there is easy expansion capability there on the solar and battery side.)


The monitor draws 4.7A and the power supply for the laptop has an output rating of 9.23A. I'm assuming the difference in voltage rating (19V for one and 19.5V for the other) is negligible.


My thought is I could wire into one of the empty 12v circuits on the power distribution panel, not one of the "top 10" that is for low current operations. https://www.progressivedyn.com/rv/po...s/4500-series/


The voltage conversion would be done with a buck transformer, e.g. https://www.amazon.com/uxcell-Conver...tronics&sr=1-3


As I understand it, upping the voltage drops the resulting current (?), so the question is, would a 20A circuit be acceptable here or does it need to be 30A? It looks like I have one 30A circuit open on the distributor, but more 20A space.


Also more generally, is there any good way to monitor total current draw on the 12v system?



Is my thinking here in line at all with reality or am I way off? Jayco obviously advises against any "alterations" but it seems to me that this is akin to adding a circuit to any other breaker box, so long as you don't overload the total capacity.

[campingva]

Why not just get a converter that changes the 12 VDC to AC in the right format for your computer. I would get one that is a true sine wave inverter. Many people use these for travel or computer use in cars. They come in various wattages one of which should fit your needs

[bradjones1]

The motivation here I think is that both appliances take DC power directly, so why go DC - AC - DC?

[JimD]

X2 on just using an inverter. So much easier. Being an electronic tech I love doing things like you are considering but it just may not be worth the hassle because an inverter does everything you need without much effort.

[Jagiven]

I wired in a couple of 12V aux outlets (flexible use). Then when we bring our computers (hate having to work when camping). I have a very small inverter I will plug in, that is just big enough.

I did a quick look on a few electronic part supplier sites, and did see some 12V -19V power adaptors. In my quick look 5A was the highest rating I saw. Digi-key would be a great place to start looking.

Have you looked at your devices, and determined if the manufacture, has a 12V power cord option? Years ago, I had one for my first laptop.

[bradjones1]

Thanks - so if I were to go that route - you're still starting with 12V, and I've already identified the circuit the USB charger is on (where I would likely tap into) is a 15A fuse. Given I would be drawing 15A *at 19V*, is this underpowered?

[JimD]

I must be missing something here as the current ratings you mentioned for your items seem rather high. I just looked at my HP laptop power supply and it only draws 2.31 amps at 19.5 volts and 1.1 amps at 120 volts. Typical LED monitors pull a lot less than what you describe. Is yours a CRT monitor?

If you went with an inverter, for the laptop alone you only would need about 250-300 watt model which would give you some spare capacity.

Converting to "watts" to see what might be required, your stated amperage requirement is about 271 watts. Using an inverter would require something in that neighborhood (very roughly).

You may be able to get by with a 500 watt inverter or may want something a little bigger to give some spare power and not push the inverter to its limit.

[campingva]

Originally Posted by bradjones1

The motivation here I think is that both appliances take DC power directly, so why go DC - AC - DC?

Agree but why try to reinvent the wheel. At the risk of damaging something beyond repair. 12 VDC outlet to inverter all done. Time for next project.