ideas on 12V computer and clean power

[Amulet]

By a solid-state adapter (Maplin or internet) which has an output in line with output voltage and wattage of your mains adapter. Most have a variety of changeable tips - however do be aware that a computer will probably be the most thirsty single item on the boat (easily outstripping the fridge compressor), though the adapters are nearly 100% efficient and produce very clean power.
For that reason eschew power-user laptops and go for CULV CPUs or even Atom-powered netbooks.

My experience is not that dire in terms of power consumption. My laptop can peak at 10 amps if the battery is empty and so being charged flat out and I'm running the computer on a profligate power scheme, but 2-4 amps is typical. I now have a machine with entirely solid state storage (laptop not netbook), but I actually got better consumption on a previous one with the disk stopped.

My fridge (smallest possible) draws 7 amps. Unfortunately the insulation is a bit pathetic and it therefore is running a lot of the time.

 

[electrosys]

I run a Thinkpad 600 (1 of 3) directly off a 12v lead-acid battery, with some inductors and zeners installed inside an empty battery-pack to remove any spikes. The result is an inexpensive, more than adequate navigational set-up.

The power draw is minimal providing the screen is switched off when the display is not being viewed. The system itself is put into hiberation when not required to ensure a much faster 'boot' than from cold. However, before engaging hibernation, it's necessary to interrupt the flow of NMEA data from the GPS, as the TP600 will not hibernate whilst data is being input. That's the only snafu I've encountered, and was solved by simply inserting a switch in the NMEA line.

The kit is so cheap to buy, that it's no problem carrying a spare laptop and gps.

 

[noelex]

Cars and trucks tend to have more transient spikes than boats.
The difference that causes more problems is the designers of "12v" systems sometimes assume a typical voltage of 13.8v (because this is the battery voltage of a running car).
The same electronics will have to cope with a bigger range of voltages on a boat 12.1- 14.7V.

In my experience it is lower voltages that cause more problems, but most car stuff lasts for a long time on a boat and is cheap to replace.
Be careful, however if you have a flattish house battery and a power supply that needs to supply maximum current such as operating a laptop that also has a flat battery. Let the laptop battery charge a bit, with the computer off, if possible.
In hot weather, with high demand, feel the temperature of the adapters (and the connections )and check they are not getting hot

 

[V1701]

I use a cigarette charger with a Samsung netbook, Open CPN, CM93 charts & a GPS dongle as a back-up to the plotter. If it was my main nav system I'd prefer the netbook to have solid state drive. At anchor, charged along with the mobile phone and HH vhf from the batteries which are charged by 60W of solar...

 

[Amulet]

Cars and trucks tend to have more transient spikes than boats.

In a previous bodged setup I used to lose communication between Laptop and GPS on starting the engine. I think it was interferance not loss of power - the laptop should be able to run on it's internal battery. I rewired it with proper shielded cable from end to end and the problem has gone away.

 

[TSB240]

Our business is considering using something like these in a very hot and humid industrial application.

http://www.seawhisper.co.uk/p126/sea-whisper--atom-16ghz-fanless-pc-16900/

 

[pappaecho]

Having just replaced the battery pack on an old HP laptop, I was surprised that the battery pack voltage is 10.5 volts, which means you could charge it from the 12 volt supply with no problems.
Its SWMBO's machine, single core processor and was running XP but recently upgraded to Win7 32 bit, and is about 5 years old. Come to think of it ...........

 

[nigelmercier]

Read the details on the mains charger for your laptop and ensure that any adaptor you buy can give enough amps...

There is more to it than just amps, volts and watts. Many laptops have a third pin in the power plug which is used to sense the power unit, so you need to get one that will give the right response. You don't need an inverter, in fact going up to 230V and down again is dumb!

Just look on eBay for: (12v, car, cigar*) (power, psu) INSERT LAPTOP MODEL HERE

 

[ffiill]

That is the most versatile laptop power adapter I've seen, plus with 5V USB to charge your phone etc.

But actually I'm thinking of taking the boat's 12V and using it with a low power PC so that it could be used underway. I don't have an inverter, plus don't want the double power loss of inverter and then a power adapter. I'm hoping there is a 11 ~ 15V DC input device which delivers a clean, spike protected steady 12V output. Don't know if there is one price reasonably, but there has got to be a lot of demand for one.

One problem I've notice with the laptop, is that the low power mode only works when it is on battery. When plugged in, even when using an inverter, the laptop uses high power display brightness and the Intel "speedstep" etc. technology is shut off. That's why a car PC, or something using the Atom line seem interesting.

Seems to me to be some misunderstanding-no need for an inverter-you can buy a product that ups your 12v DC to whatever DC voltage your laptop normally runs on-again recall mine is 19v DC.
The plug into back of your laptop is normally fed this DC voltage from inline transformer on your power cable.

 

[noelex]

Having just replaced the battery pack on an old HP laptop, I was surprised that the battery pack voltage is 10.5 volts, which means you could charge it from the 12 volt supply with no problems.
..

The lithium ion batteries in computers need careful charging. The batteries can explode and burn with a fire that is very difficult to put out. Not nice on a boat.
Lithium chargers will upscale the voltage from 12v to whatever the battery pack requires.

Do not connect a lithium computer battery directly to 12v.

You can charge the battery packs with a proper lithium charger, but its far easier to use a DC to Dc converter and let the computer take care of managing the battery

 

[contessaman]

Is anyone running a low power PC, like a 12Volt "car PC" on their boat? My laptop only runs for a few hours, and am toying with the idea of putting a low power PC to run GPS software at the Nav station. I don't like the idea of an inverter, then a power adapter, so I've read a little on lower power 12 Volt computers used in cars and some trucks. Anyone used one?

A related issue is trying to ensure that "clean" 12 Volts gets to the computer, as they tend to be finicky about power. I'm thinking there may be many voltage spikes on a boat, like if a bilge pump or other device turns on. Another problem is 12V on a boat is very often 13.x volts.

All suggestions appreciated.

yep built one myself, spent a while getting current as low as possible, but its good as you will see: 1.1amps total with 12" tft on, running tsunamis 99 and includes 150 ma for usb gps. when monitor goes off its down to 0.5 amps. comparable to a normal gps rx. got the nasa pc navtex set up with it too thats great.

spec:

mini itx 500 mhz motherboard (took apart a thin client computer) - £10 ebay
opus (usa) 12v vehicle PSU - £25 ebay
hard disk is solid state 4gb compact flash card with ide adapter - no moving parts and negligable current consumption
custom aluminum case - welded up for beer money by guys at work
best bit -stainless waterproof panel mount keyboard with trackball (from payphone style internet computer) £20 ebay
usb gps receiver £5 ebay.
Tsunami 99 software - free from mate at work

Monitor bit subjective. I have found that most electronic point of sale (till monitors) have a 12v input. first one I got for £20 was a sanyo - took 0.8 amps. second was unbranded but took 1 amp (but this was very bright - might set it in a waterproof housing at helm one day) third was a digipos one and to my utter happiness it cost £8 on ebay and took 0.6 amps! all are 12" tft.

if you want low current heres a few tips based on my trial and error:

1)
go for low spec pc: you dont need lots of ghz to run plotter and navtex. the best board of all is the via mini itx with the 500 mhz eden processor. I added more memory but that just took more current so I removed it. 256 mb runs windows xp and tsunami fine. It doesnt stream video well but who cares.

2)
power supplies. cheap ATX 12 volt power supplies off ebay are designed for regulated 12 vdc from a power supply. your 12 to 14.4 with engine running will doubtless fry it and the computer and will crash the software to with any spikes. you need a proper vehichle PSU. i was luck with a second hand opus one on ebay. this will be the most expensive item. same goes for the monitors 12v input. boat supply is too harsh but as you dont need disk drives the computer PSU can give the stabilised 12v. computers use 5v and 12v so you need the black and yellow wires off the power supply and you can power your monitor off this. again this is why a good psu is the most critical part of the setup. mines 80 watts so can easilt handle the monitor too.

3)
stay away from laptops, inverters and those cheap lighter socket PSU that turn 12volt into 19volt for laptop. these all work fine but in answer to your OP you wont get that ultimate low power consumption this way.

you can get most of what you need here:

http://linitx.com/

but you'll pay a lot. you'll have to go secondhand for motherboard. start keeping an eye out on ebay for an eden board. they are about 8-9 years old. the newer boards are all about performance but take more power.

the above isnt gospel, my computer knowledge is basic (but I learned a lot making this system) but it all works great for me.
Finally, the 0.6 amp monitor is fine below decks and even in the wheelhouse of my boat but isnt bright enough for direct sunlight. you'll need a brighter one at about 1 amp consumption for that(outside use). but dont forget you can set windows to turn monitor off after 5 mins so you ampere-hour consumption will still be low.

I reckon my solar panel can power both my marine pc an my autohelm under sail. happy days.

have fun!

 

[contessaman]

forgot to say, this is the make of the stabilised vehichle PSU:

http://www.opussolutions.com/

mines a discontinued model, but theres plenty similar. Its so well stabilised you can start the engine of the same battery and the computer does not blink.

other makes:

http://linitx.com/viewcategory.php?catid=54

the good ones dont get hot as they regulate the voltage by chopping rather than turning it into heat (and wasting valuable amps).

this is motherboard, they did two models, you want the eden 500mhz:

http://www.via.com.tw/en/products/embedded/ProductDetail.jsp?id=21

mine came in a cheap 'wyse winterm' pc that I took apart.

 

[Bobobolinsky]

Mine was a mini itx, with a touch sensitive screen. Worked well until stolen

 

[Amulet]

In my hands this is simpler than some would have you believe.

Maybe I'm just lucky, but of my last four laptops, three have had chargers with two wires going to the computer ending in a circular plug with the -ve outside and the +ve inside. (Different voltages.) All I have done is run them from a Maplin car adaptor with sufficient wattage and set to the right voltage (determined by reading the spec on the computer mains charger). The car charger came with an array of alternative tips which included all the necessary ones for the three laptops, and everything worked perfectly. The fourth laptop had a bizarre plug which bore no resemblance to anything I'd seen. I scrounged a spare mains charger from someone and chopped its lead off to reveal again 2 wires. I bought a socket from Maplin and soldered up a lead which enabled my existing car adaptor to connect via the tail end transplanted from the mains charger. It worked perfectly too. So in my hands the task seems much simpler than others have found it. I have also made the same kind of approach work for two friends.

Noted above, but not put bluntly: it your laptop is getting its 19 volts (or whatever it needs) up its jacksey, it has no way of knowing whether it is plugged into your boat battery, mains or you exercise bike, and will, by default, adopt a power hungry regime rather than the lean regime used when it is on its own battery. If you want to be kind to your boat battery you will adjust this. I usually stop the hard disk (solid state on my latest so no help now), switch off the DVD drive and dim the screen. You can let it switch the screen off when you're not looking at it, but I like it on but dim.

 

[farmer.leo]

For the 17-inch screen we have used a 12V-12V converter, to ensure a clean 12V supply,

Could you tell me more about this device? Not sure how 12V is being "converted" to 12V, but it sounds exactly what I'm thinking about, clean power and isolation from spikes and sags.

I'm wondering if you might want to power both the PC and the monitor from this.

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And to everybody else, great ideas and references. Definitely a very helpful board here.

 

[nimbusgb]

12v to 12v Dc/DC converter does 2 things.

1 - ensures a completely stable 12v output, filtering or smoothing out spikes and charging voltage increases from the supply.

2 - most will offer electrical isolation from the supply. So the output side ground and 12v are isolated from the battery circuit.

1 amp ones ( 12 Watt ) tend to be pricey

Heres one at 1.25 Amp output - 9 - 36 volts in and a 12v out at 1.25 amps and 1500v isolation

These units are switching power supplies in one guise or another so you may end up with 300 kHz interference on VHF, radio etc. Using a good aluminium housing grounded with input and possibly output filters is advisable.

 

[westhinder]

Could you tell me more about this device? Not sure how 12V is being "converted" to 12V, but it sounds exactly what I'm thinking about, clean power and isolation from spikes and sags.

I'm wondering if you might want to power both the PC and the monitor from this.

--------

And to everybody else, great ideas and references. Definitely a very helpful board here.

As I understand it, a converter changes dc current from one voltage to another. There is however also a 12V to 12V converter, which is used to provide a clean 12V supply without any drops or spikes. I think it is not necessary to run the pc from it, as the power supply in these devices for the car and truck industry does effectively iron out any drops or spikes.
I am sure other, more technically minded forumites will be able to explain this more accurately.
Edit: So far I have not noticed any interference

 

[Amulet]

This is dead easy

As I said - I have made this work with six different laptops by simply plugging in a Maplin car charger - no problems whatsever. In a previous thread, someone said that they'd put the Maplin output on an oscilliscope and it was flat. I'm not convinced that you need a very clean supply anyway. I.e., this is dead easy.

I previously tried an invertor and it worked but consumed about twice as much current as the DC to DC.

 

[Conachair]

As I said - I have made this work with six different laptops by simply plugging in a Maplin car charger - no problems whatsever. In a previous thread, someone said that they'd put the Maplin output on an oscilliscope and it was flat. I'm not convinced that you need a very clean supply anyway. I.e., this is dead easy.

I previously tried an invertor and it worked but consumed about twice as much current as the DC to DC.

Just tried it again with a scope on a maplins 12v-19v car supply, flat with fridge switching on and off and with water pump, but dropped down to about half voltage for a second when starter motor is used.

 

[contessaman]

Just tried it again with a scope on a maplins 12v-19v car supply, flat with fridge switching on and off and with water pump, but dropped down to about half voltage for a second when starter motor is used.

seems reasonable if you want to go down the laptop route - you could probably improve that further with one of those enormous capacitors that boy racers fit into their car stereo supplies. theyre not too expensive.