Using 12v System to Directly Power Computers and other DC Eq.

[Portager]

StianM;

JPC initiated this thread by saying, "Since so many products are DC (but call for varying voltage levels and are designed to rely on specific AC adaptors in home applications) it seems that it would be efficient to power these directly from the 12v source."

I was responding to the original question of improving the overall efficiency, which is important on a small boat with a limited battery bank or on a small boat in the tropics without air conditioning.

[StianM]

Originally Posted by Portager

StianM;
I was responding to the original question of improving the overall efficiency, which is important on a small boat with a limited battery bank or on a small boat in the tropics without air conditioning.

I gues it's true what they say, everything is biger in america. The powersupply to my asus 17inch nootebook is only 4.74A, my girlfriends Tatung nootbook computers powersuply is only 1.2A. The stuff you have ower in california must be huge since it's a power concern with you.

[TerryKing]

Originally Posted by Portager

(snip)..."It is more efficient to power DC loads off DC power even if you need a DC to DC converter."

I agree, and for those making a passage under sail or anchoring for a few days in a remote spot, efficiency is important.

I'm looking to find a series of low-cost DC-DC converters that are 12V (nominal) in and have a variety of outputs available (settable). I'd like to mount them at point-of-use, have them somewhat interchangeable (within a similar power rating) and have standard 12V connectors for many low-current 12V based devices, utility lights, etc etc.

Portager, have you decided on DC connectors yet? My Son was discusing this with Jack Ganssle (Of Embedded Computer fame) who, is also a sailor. Jack uses a widely-available 4-pin connector that has a bayonet secure attachment. I'll find out which one it was and it's availablity. I have been using the old 4-pin polarized "Jones Plugs" for 20 years, but Radio Shack doesn't carry them any more!

Maybe we can work up some stuff for the Electrical Systems Wiki later on...

[hmattos]

I agree with Trelyns at post #10.
Why re-invent the wheel when you can go down to most hardware or automotive / tool stores and buy a 150 watt power invertor which will give you a good safe sine wave at 230 or 110 volts.
The cost, all ready to use, is less that 20 GBP which probably means about 30 dollars.
Great for use in the car to keep the children amused with a DVD on the laptop for the journey.

[Tim B]

Maplin still have "Locking Audio Connectors" Which are actually capable of handling a fair bit of power (I'm using them on my boat at the moment). Farnell also have a wide range of suitable connectors.

The last inverter I bought cost me £75. That's a lot more than 75p for a voltage regulator to run a mobile phone off.

Tim B.

[TerryKing]

Originally Posted by Tim B

Maplin still have "Locking Audio Connectors" Which are actually capable of handling a fair bit of power (I'm using them on my boat at the moment)

Tim, can you point to a picture / page with these connectors?? I'm trying to survey the possibilities, not just US stuff...

[Tim B]

These are they:

http://www.maplin.co.uk/search.aspx?...id=-2&doy=20m5

It's not a perfect solution, but it does mean that you can have a multi-pole connecter in a standard plate. XLR connectors also spring to mind.

Tim B.

[TerryKing]

Originally Posted by Tim B

It's not a perfect solution, but it does mean that you can have a multi-pole connecter in a standard plate.

Tim, I think the connectors Jack Ganssle and my Son were looking at were very similar, but Delrin plastic with an O-ring seal. Maybe better in Marine environment. I'll track them down and we can compare....

[TerryKing]

Assuming that adding to a list is an actual accomlishment, I have added:
# 8.3 Electrical Connectors for Shipboard Applications
As a section on the electrical Systems Wiki..

I'll put some stuff there soon, including the Maplin reference.

The worldwide property of boating is a challenge...

[JPC]

I've been away from the forum for a while, and it looks like this thread ran its course some time ago, but I thought I'd close the loop by describing where I'd ended up.

Since I had asked the original question and was looking for new (to me) information, I stayed quiet once the thread got underway, but was closely following most of the discussion and am grateful for the thoughts and contributions that were given.

Focusing on just a few of the main points, I was looking for:

1. low power;
2. reasonable robustness;
3. minimal number of additional 'parts' and connections (applying to both things like add-in video cards and things like inverters, DC converters, etc.);
4. availability, implementation, and costs in line with generic 'land' devices and not specialty marine items.

The system was to be used on a 34' sailboat; an environment that can get wet and bouncy, and a situation where power is a scarce resource. This system is principally used for navigation and communication tasks and is meant to be operating 100% of the time that the boat is not at anchor.

I'm using the Alix 1C motherboard ( http://www.pcengines.ch/alix1c.htm ) and the Hyvision MV142 14" LCD monitor. Both operate directly from a 12v DC source and consume, respectively and when not in snooze, about 5 watts and 13 watts. Within reasonable functionality, I haven't seen anything more power-stingy. Neither requires an inverter, power supply, or DC converter.

Low power means a modest machine. The Mboard has a 500MHz processor and a fixed (soldered on board) 256MB of RAM. So far, this has been fine, particularly when operating with some of the low-overhead versions of Linux (Xubuntu, Fluxbuntu, e.g.).

The Mboard further saves power and the risk/cost of additional components and their connections by having integrated sound, video, LAN, etc. No screamers, but it's all there and won't rattle loose or bleed more power. The board is intended to use a Compact Flash drive as its primary drive; it can also use and boot from USB drives or a standard CD or HDD connected by USB or the one EIDE header. Sticking with the CF or USB flash drive preserves the low power and makes for a fully functioning system with no moving parts or significant add-on pieces; this goes a long way in acheiving the robustness objective. Additional, or higher performance, storage or other devices can be plugged into the USB, EIDE, or PCI bus only when needed, so won't suck power or create a vulnerability when they're not required.

Finally, the Mboard is fanless and generates negligible heat, allowing it to operate in a water-tight enclosure without overheating, solving a lot of hassles.


It's cheap and it works. Everyone's applications are different; this one has been fine for me. Those looking for more power/capability than this, while still avoiding a standard desktop or laptop might find some interesting options at http://www.mini-box.com. If anyone's looking to do a similar thing and would like some more sources, just shoot me an email -most of my info is on a cantankerous hard drive, but if I can ressurect it I might be able to save you some time.

I've been fiddling around with a full desktop-power arrangement as well, using a sealed case and water cooling. That's more of a curiousity than a real effort, but I'll relay any info (or tales of bursting pipes) that seems useful.

Best regards,
JPC

[masalai]

Some here (connectors) - all in Australian $ including 10% gst?

http://www.dse.com.au/cgi-bin/dse.st...ogs/CTG0005745
or
http://www.dse.com.au/cgi-bin/dse.st...ogs/CTG0001202

and dc - dc converters here (with thumbnails)

http://dseau.resultspage.com/search.....y=8&submit=Go

Regards.