Best power system for computer

[Chuckbear]

I'm not too sure about that. Modern invertors are pretty efficient, and since the easiest way to change voltage for DC is to convert to AC (or at least chop it), and change back to DC, I suspect the DC-DC converters actually have in inverter in them.

If your laptop runs on 12VDC or less, the battery is definitely the way to go. Otherwise... too close to call!

druid

Not even close when it comes to efficiency. Chuck

 

[wonkodsane]

Did anybody mention Maine Sail's experiments on this yet?

http://forums.sbo.sailboatowners.com/showthread.php?t=114302

He also did a side-by-side of powering a tv/dvd through an inverter and just off of 12V on another post.

http://forums.sbo.sailboatowners.com/showthread.php?t=101672

Good info from him as usual.

 

[Maine Sail]

I'm not too sure about that. Modern invertors are pretty efficient, and since the easiest way to change voltage for DC is to convert to AC (or at least chop it), and change back to DC, I suspect the DC-DC converters actually have in inverter in them.

If your laptop runs on 12VDC or less, the battery is definitely the way to go. Otherwise... too close to call!

druid

Where do you come up with this stuff?

ASUS Netbook eeePC

12V Adapter = 3.12 Amps
120V/150 Watt Inverter = 4.12 amps

Total Inefficiency With Inverter = 32.05%

Polaroid 19" TV

12V Direct = 3.9 Amps
120V/1200 Watt Inverter = 5.8 amps
120V/400 Watt Inverter = 5.2 amps

Total Inefficiency With 1200W Inverter = 32.8%
Total Inefficiency With 400W Inverter = 25%


Inverters are most efficient at close to their rated outputs but even at that inverters can vary widely in efficiency. The inverters used in the above scenarios all claim about 90% efficient..
A quote from Practical Sailor:

"Efficiency figures will vary based on demand load and battery voltage; most inverters’ efficiency will improve with higher loads. All test products were rated for efficiency using the same loads and voltage."

This batch of 8 inverters recently tested by PS ranged from a low of 73% efficient to a high of 93%. These efficiencies are without any conversion inefficiencies like you would have running a computer or TV that is already internally DC off DC to AC and back to DC or the fact that you may be running it at well below its rating..

For the full article subscribe to Practical Sailor (LINK)..

 

[Sumner]

A few weeks ago I was under the impression that a computer that ran on 12 volts, like the eeePC's, would be fine on a battery orientated system like on our boats. But like Maine and others have pointed out they are designed to run on a specific voltage, such as, 12 volts only or very, very close to it. Out systems might have a 12 volt battery in them, but will run from below 12 volts when the battery is low or especially when starting the engine to over 14 volts when charging.

I'm in the process of building a 12 volt computer and thought I just needed a 12 volt input power supply like this....

http://www.mini-box.com/picoPSU-150-XT

...one for it, but found out that it like most laptops requires a steady 12 volt input. What I really need is a ...

http://www.mini-box.com/M3-ATX-DC-DC-ATX-Automotive-Computer-car-PC-Power-Supply?sc=

.... power supply like above that operates with inputs of 6volts to 24 volts and will output a regulated 12 volts and 5 volts for the mother board. You can also set it up to completely shut off the computer power on the 5 volt line after a given time period.

If you have a small desktop computer with an ATX motherboard, you can pull the power supply in it and plug one of these into the motherboard where the power supply plugged in and run the computer straight off your boat's power.

Until I can finish this.....

http://purplesagetradingpost.com/sumner/macgregor2/Comp-ChartPlot-Index.html

....build we run our two Dell laptops off of a Lind DC to DC....

http://www.lindelectronics.com/cgi-..._Adapters/x/dbx_gen_Special_DC_Adapters_mfgs/

...converter (one at a time). They cost a little more, but are great products and well worth the additional cost.

c ya,

Sum

Our Trips to Lake Powell, UT - Kootenay Lake, Canada - Priest Lake, ID

Our Mac Pages

Mac Links

 

[kenn]

Nice links, Sumner!

A purpose-built computer, designed to be powered from marine or auto 12v systems is the grail.

I trashed a 160GB harddrive this year by bumping my PC hard (while vacuuming! ). I have my worries about how long a conventional spinning-plate hard-drive would last in a moving boat, especially during the rough stuff, so this would be a good place to use a solid-state HD, with maybe a USB hard-drive available for use when it's calmer.

I'm looking forward to watching your project.

Cheers!

 

[Chuckbear]

Nice links, Sumner!

A purpose-built computer, designed to be powered from marine or auto 12v systems is the grail.

I trashed a 160GB harddrive this year by bumping my PC hard (while vacuuming! ). I have my worries about how long a conventional spinning-plate hard-drive would last in a moving boat, especially during the rough stuff, so this would be a good place to use a solid-state HD, with maybe a USB hard-drive available for use when it's calmer.

I'm looking forward to watching your project.

Cheers!

The only thing I can add to this is our experience with our laptop running at the nav station during some pretty rough offshore conditions including a full gale for almost 24 hours and the laptop never missed a beat. Our friends, with a desktop on board, in the same storm, also running, never had an issue and both computers are still running a couple of years later. Chuck

 

[Sumner]

Nice links, Sumner!

A purpose-built computer, designed to be powered from marine or auto 12v systems is the grail.

I trashed a 160GB harddrive this year by bumping my PC hard (while vacuuming! ). I have my worries about how long a conventional spinning-plate hard-drive would last in a moving boat, especially during the rough stuff, so this would be a good place to use a solid-state HD, with maybe a USB hard-drive available for use when it's calmer.

I'm looking forward to watching your project.

Cheers!

Thanks. I'll be using a lap-top 2 1/2 inch HD in it for those very reasons. We need to take a trip, buy a new outboard and some other boating stuff, so the computer/chartplotter is probably on hold to about May :cry:. I'll post when it moves along. I do have a pretty complete shopping list at this point and will probably post it soon if there is any interest.

I started a computer store from scratch in the mid 80's and built and sold tons of PC clones before selling the business in '90 thinking I had enough to retire on. Well the retirement lasted about 3 years :cry: before I had to start another business. So now after all of this time I'm putting a computer together from scratch again. I'm starting to believe the saying 'that if you wait long enough things will go full circle'. I just hope this time I will only be building 1 or 2 computers and not hundreds .

c ya,

Sum

Our Trips to Lake Powell, UT - Kootenay Lake, Canada - Priest Lake, ID

Our Mac Pages

Mac Links

 

[shorty]

I have the Targus 800-0084-001 A, 70W for my Toshiba. Very happy with it. Use it for 100-230VAC & 11.75-16VDC inputs. I think it was somewhere around $40-50.