Inverter vs. DC-DC converter.

[GrantRobertson]

I've been looking into ways to run as much stuff as possible on 12vdc. I'm having a bit of trouble finding computer monitors and desktop computer power supplies that accept 12vdc rather than 120vac. Heck, even the Technomadia folks use an inverter for their computer monitors. So, the other option is to hack into said devices and feed 12-15vdc directly into the output of the rectifier. This part, I can do relatively easily.

The question is: Which wastes less electricity, an inverter or a DC-DC converter? My immediate assumption is that inverters (plus the 120v a.c. power supplies) are more wasteful. However, I have learned not to assume anything. Does anyone here have any specific info?

 

[B and C]

I use the HDMI input on my cheap 19" TV (Hisense?) for a monitor with my desktop.  It also has a VGA port if you want to connect to it that way.  Both run on 12v.  The TV I bought a Wallyworld for ~$100.  It came with a wall wart that converted 110v to 12v.  I just got rid of the wall wart and wired it in directly.  Monitor and TV in one (servers two purposes.  My computer, an HP 800 Elitedesk Mini desktop (I7) is the size of a small book with an external USB BluRay/DVD player and a couple of external 2 TB drives that contain my movie collection.  It uses the same HP 12v adapter that my laptop uses.  12v in 19v out at 95 watts.

Brian

 

[sushidog]

They are usually about equal in efficiency. There is more of a difference between the quality of the inverter/converter than the type. They usually run from round 82% to 95% efficiency. Most are in the 85-88% range. The more you spend the better they get. If getting an inverter for electronics insist on a PSW inverter, as the device will last longer and typically use the power more efficiently too. BTW really good DC-DC converters are available but very expensive, just like really good PSW inverters. But if you decide to go with one of the really high end units, a DC-DC converter might get you 1-2% better conversion efficiency.

Chip

 

[akrvbob]

In my opinion, another 100 watt solar panel would pay off a LOT more than going through all that.
Bob

 

[GrantRobertson]

I use the HDMI input on my cheap 19" TV (Hisense?) for a monitor with my desktop.

What's the resolution on that TV?

 

[GrantRobertson]

In my opinion, another 100 watt solar panel would pay off a LOT more than going through all that.
Bob

That's about what I figured. If you also consider the negligible difference, and the fact that I will need an inverter anyway, it doesn't seem worth the trouble.

Thanks.

 

[B and C]

What's the resolution on that TV?

You made me go look to see the brand.  It is an Element and the resolution is 720P or 1280x720.  On a 19" inch screen, it is plenty for these old eyes.

 

[jimindenver]

Foe years we had most everything running off of 12v. TV, DVD, fans, phones, computers, even a coffee pot. Last year we got the satellite receiver that had to have a inverter so it just became easier to switch back to 120v for those items.

 

[GrantRobertson]

You made me go look to see the brand.  It is an Element and the resolution is 720P or 1280x720.  On a 19" inch screen, it is plenty for these old eyes.

My eyes are pretty old too but I need higher resolution and a larger screen. Thanks though.

 

[blars]

If you run an 85% efficient wall wart off an 85% efficient inverter, you are only 72% efficient. Transformer style wall-warts may not like MSW inverters, but are getting less common. Switching wall warts tend to be lighter, smaller, more efficient, and have a wider input voltage range.

 

[SternWake]

My laptop DC to DC converter uses significantly less juice than does my 400 watt pure sine wave inverter powering the original power brick.


I did a direct test, but can;t find the numbers, but the DC to DCC converter was using about 20 to 30% less than the inverter that was turned on and only powering the original power brick.

The laptop varies the load so quickly, the amp draw numbers bounce around quickly.

If the 30 watt draw is OK, but 45 watts is going to break your energy budget, you need more energy anyway.

Sometimes a small energy savings is not worth the effort.

This device can step up voltage easily, and cheaply:

http://www.amazon.com/DROK-Converte...22&sr=1-12&keywords=step+up+voltage+converter

http://www.amazon.com/DROK-Transfor...CfWqCYL&dpSrc=sims&preST=_AC_UL160_SR160,160_


http://www.amazon.com/Geeetech-Conv...5xuVVLL&dpSrc=sims&preST=_AC_UL160_SR160,160_

I try to use the inverter as little as possible as it can wipe out some TV stations or weaken them, but then again so can my laptop DC to DC converter, and some LED lights.