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Do you find that it's more power efficient to run a custom built machine like that? I would think that using a laptop as your daily driver would stretch your battery bank further, since it's designed from the ground up for battery power. I lived off solar power for a while, and that was my thinking. I never did the math to verify it though.

I haven't done any measurements.

What I will say is that the machine I used to use in the van lost its video output (the perils of onboard graphics), and I've found it impossible to source a reasonable replacement mobo. As a result, I've switched back to using a laptop (lenovo Y700) in the van.

What I notice as a potential improvement is that it effectively lets me store an extra X hours of power for computing, because I'm adding the laptop battery to the overall storage. Compared to my "house batteries", the laptop batteries are of course very small. But getting (say) 3 hours of work time stored up in the laptop does seem like a plus, especially on cloudier days.

The trends definitely favor a mobile-first approach going forward, if simply because of the additional systems integration work that goes into tuning laptops. Battery life aside, the laws of physics dictate that you're more likely to have a reliable experience with a low-power, low-heat, low-vibration machine than a screamer desktop, and those things are definitely qualities that the manufactuers optimize for in mobile devices.

It's also increasingly common to see single-board SFF desktops that are essentially laptop parts with different I/O. I suspect that those are less heavily tuned, though.

problem for me: i need a screamer desktop. i'm not online or running JS in the browser, i'm developing and building software that used to take 9 minutes to compile from scratch on those 12VDC systems. Over and over again.

at home now i have a 16 core ryzen, which is extremely quiet and very, very much faster than those systems. but i don't think it would be possible to host this on a 12VDC PSU, and even if it was, the mobo form factor is inappropriate for the space i built in the van :(

to be fair, the lenovo Y700 was/is essentially as fast as the 12VDC systems, which is quite impressive.

>not some noisy-ass AC/DC conversion

https://www.jonnyguru.com/blog/2018/07/03/seasonic-prime-ult...

Is 30 dB SNR insufficient for a digital system?

> My guess is that someone figured out how to shrink the necessary converters to a size that made it more "sensible" to put them inside the monitor

I’m under the impression that this was demand/market forces. It used to be much cheaper to have an external brick rather than engineer a power supply into a monitor. However, the engineering cost was lower than the missed sales due to consumers not wanting external power supplies. It’s just another thing to lose. Another unique plug you’ll never be able to reasonably replace with what’s on hand.

"noisy" in this context referred to the output signal, not the acoustic levels.

Also, the 12VDC native monitor that I did buy didn't have a unique plug. It used the fairly standard ring/core 12VDC jack and plug found in many different contexts, though not a lot of digital ones.

12V / 6mV is ~33 dB SNR. What’s more is that the 6 mV ripple on this supply’s 12V rail is p-p and not RMS. So for most apples to apples measurements it’d be more accurate to say the SNR is closer to 35 dB.

Regardless, seasonic supplies, and this one in particular, are very low noise. Most supplies are closer to 30mV ripple on the 12V rail.

Whoops. This should be 66-70 dB. I accidentally used power log rather than voltage log.

My 4k Monoprice monitor is 12V. So it's not as impossible as you think.

I'm just waiting for electric vehicles and their technology to invade the van and RV market.

It would be really cool to have a solar/battery powered vehicle you can power from DC. A bus-sized RV could easily generate 5kw from current solar panels just on it's roof.

Current RVs do have both 110v AC and 12v DC systems, but they're not easily integrated. 12v is too low to power bigger stuff like air conditioners (1500 watts = 125 amp wiring!) and converting DC to AC requires expensive inverters.

A really cool solution would be high-voltage DC powering DC appliances directly and stepping down to clean lower voltage DC close to where it's needed.

Electric vehicles are a long way from the sort of mileage that would allow them to effectively replace vans and RVs. We routinely drive 5-800 miles in a day in our van. This isn't going to be possible until battery replacement takes over from battery charging.

And yes, our van has 120VAC (1kW) available, but I prefer to use it only for things where's there no alternative (e.g. our toaster, or recharging laptops, sigh).

As far rooftop, we have the long Sprinter with about as much solar as you can get on the roof given that you need (at least) an exhaust fan. That gets us to 540W. The most I've ever seen on a van was 3kW and that was an ... insane ... physical setup.

I bought a tesla 700 miles away and drove it home the same day.

As to RVs and vans:

- the cybertruck ships in the next year with 500 miles range, and will charge at 250kw/1000 miles per hour

- the tesla semi is coming soon

- other companies are entering the game

- people have been putting lithium ion batteries in their RVs.

- EVs have electric air conditioners now.

Separately I will say if you're driving an RV 5-800 miles in a day (regardless of power source) that's a really hard trip. I find 300 miles in the saddle taxing and 150-200 lots nicer. Leave, drive and arrive during daylight hours and enjoy the trip.

I wouldn't want to drive 5-800 miles a day every day, and I don't. But when we do (e.g. just trying to get somewhere before staying there for a while), I don't want to be cramped in that way.

The cybertruck charging rate sounds great, but where are the charging stations? You know, the ones in southeastern Oregon or southwestern New Mexico?

I'm not trying to be a debbie-downer about this. I absolutely believe in an electrical vehicle future. But I don't believe it will happen via charging - it will happen via battery swapping, probably using a standard mandated by national (or international) level bodies.

https://www.tesla.com/supercharger

https://www.plugshare.com/

any rv park

You should be able to use a DC-DC converter for charging the laptop off the DC - they're sold as "laptop car charger" or similar and have a cigarette-lighter-style plug.

I'm excited for the upcoming all electric Ford Transit! That's got E-RV conversion written all over it!

No it's got local delivery and workman written all over it. Unless you're going to go rv at the local supercenter.

Rv parks and campgrounds will limit your pull from the mains and when someone starts pulling serious juice from their campsites they'll start auditing.

More likely they'll just start charging (ha!) for it.

I really don't think people take exactly that into account.

Right now, and even for the past few decades, electrical use tended to be offered as either a freebie with just being somewhere as a guest or renter, or was generally priced in with discount for conglomerate use. As more and more power intensive appliances become more common (I.e, shift to E.V.) the pricing model is likely to have to change.

Right now you can host 100's of people at a campground, even with an AC on say every third, or every other camper. Throw 100 electric vehicles having to charge at the same time, and you may find the bill has to pass on to users just to be viable.

I was recently wondering if 12VDC shouldn't become the new current standard for inside homes. Everything is still 230VAC (in the EU at least, I think the US uses 110V?), which is way too much for a lot of household appliances. The only reason modern LED bulbs are hot and expensive is that they need to convert down to 12V from 230V. It's mostly washing machines and kitchen appliances that need that much (and some of those even need 380V).

Almost everything in the home needs adapters and power bricks to convert it to something sensible, which usually is 12VDC. So why not just make that the standard?

> So why not just make that the standard?

Power loss in cables at low voltage / high amps.

The vast majority of the thermal output of a modern led is the led itself.

Monitors were still 12V inside last time I checked (5 years ago), they're basically integrating the PSU into the monitors because they use less power and can be smaller/run cooler.

It's very likely you can just bypass the internal PSU on any monitor and power it straight from your battery.

You'll just need to take it apart, which can be hard depending on the housing.

> I built (on an ATX form factor) were 12VDC native

I want this! Mainly to run from batteries efficiently, transforming from DC to AC and then back to DC is so absurd. Can you give any photos/links/recommendations on how to start?

Sadly, I mistyped the above. I used ITX mobos, not ATX. However, you can get started by taking a look here: http://mini-box.com/ and in particular the "picoPSU" section.

A few images and details of one of the systems I built here: https://sprinter-source.com/forum/showpost.php?p=289185&post...

Thank you. Where did you get the 12V power supply, from a car battery? Or a solar panel?

My van has 455aH of storage in lead acid AGM batteries, charged by 540W of solar panels and a solar charge controller. The batteries power a 12VDC service panel; one of the circuits runs to the computer/office area, where I have a voltage regulator to keep the voltage within limits when the solar charger decides to ramp things up to high for the picoPSU.

I just bought a 1440p ViewSonic with an external brick.