Laptop power ?

nimbusgb said:
Samsung NC10 - completely flat battery - Amazon 'samsung' 12v/19v converter. 3.7 Amps. once fully charged it draws about 800ma depending on screen brightness and what the laptop is doing at the time.

150w Maplin inverter, no load - 200 ma ! using the Samsung mains adaptor 5.3 amps.

1500w pure sinewave inverter - no load - 1.2 amps
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I had an IBM thinkpad (T23) which would draw 6A from an IBM 12V adaptor if the laptop battery was fully discharged. This would drop considerably as the battery charged up.

I now have a Panasonic M34 which, with a fully charged battery (or with the battery removed) will draw 1.1A, reducing to 0.7A with the screen off.

John
 
I was in an electrical supply shop "Tanners", in Cardiff yesterday and the assistant was extremely helpful.
It seems that 1400w is more than enough for my needs in my Hurley 24.
Another good point he made was the type of inverter.
Apparently, it has to be of a pure sinewave type, or else it is possible to damage the screen on TV's & Laptops.
 
Amulet said:
See: this thread, this thread, this thread, this thread and this thread for more discussion of this topic.

[I mean to be helpful, not snotty.]
Click to expand...

I like to "chew the crud" myself sometimes.
Ime sure i could obtain the relevant info from many, many, many, many other sources, but no fun in that. Ps that applies to every single question ever asked on this forum.
(just being honest not snotty)
 
Gelmaster said:
I was in an electrical supply shop "Tanners", in Cardiff yesterday and the assistant was extremely helpful.
It seems that 1400w is more than enough for my needs in my Hurley 24.
Another good point he made was the type of inverter.
Apparently, it has to be of a pure sinewave type, or else it is possible to damage the screen on TV's & Laptops.
Click to expand...

Most thing will run on an inverter that is not pure sine wave, but not everything. Some things will also run a bit hotter.
The cost of pure sine wave inverters has been coming down and I would buy a pure sine wave model these days.
1400w is easily enough. I think you will find its really to big. If running at full capacity it will be drawing 130 +A. Not many 24 foot boats can support that sort of load.
 
TQA said:
Most lappies need 19 volts. If the little suckers would run off 12 volts life would be simpler.
Click to expand...

They used to. I've just dumped an Omnibook 800 that ran for years from the boat's 12v with minimal power consumption (but minimal memory and processing power, small screen, few colours and no USB, BIOS that didn't support disks larger than 8GB ... and more [less actually] ).

Progress, but at what price?
 
Gelmaster said:
I like to "chew the crud" myself sometimes.
Ime sure i could obtain the relevant info from many, many, many, many other sources, but no fun in that. Ps that applies to every single question ever asked on this forum.
(just being honest not snotty)
Click to expand...
No criticism intended for raising it again. Just thought you might want to look at the old stuff too - and I was to lazy to retype all my extremely wise comments on previous threads - or even copy and paste them!
 
Gelmaster said:
Apparently, it has to be of a pure sinewave type, or else it is possible to damage the screen on TV's & Laptops.
Click to expand...

I'm a bit mystified by this comment. I could understand if he said it would damage the power supply but as every laptop I can think of runs on somewhere between 12v-24v DC I don't see how the AC input to the power supply (transformer/rectifier) could possibly have an impact on the computer itself. :confused:

My laptop power supply runs happily off a modified square wave inverter (ie non-sine wave) and although the transformer makes some strange noises and runs a little hotter it has no effect on the lappie at all.
 
emsworthy said:
My laptop power supply runs happily off a modified square wave inverter (ie non-sine wave) and although the transformer makes some strange noises and runs a little hotter it has no effect on the lappie at all.
Click to expand...

If worried about damaging equipment I would sooner use a mains adapter plugged into a cheap inverter than a 12 volt adapter. I have both and the 12v adapter produces enough electrical noise to make the audio output of the laptop unusable for watching DVDs.
 
noelex said:
Most thing will run on an inverter that is not pure sine wave, but not everything. Some things will also run a bit hotter.
The cost of pure sine wave inverters has been coming down and I would buy a pure sine wave model these days.
1400w is easily enough. I think you will find its really to big. If running at full capacity it will be drawing 130 +A. Not many 24 foot boats can support that sort of load.
Click to expand...

Most of the inverters i have seen, seem to be pure sinewave now, even the cheaper end of the market.
Can you by any chance recommend a suitable sized inverter size for me?

I am rebuilding my boat from scratch and here is a list of what i am planning to run.......

Port & Star Nav lights
Bow and stern? do i need?
Steaming light
Mast top lighting
4x Small cockpit lights
10 "Led" cabin lights
2x shower lights.......i love my lights!
VHF
GPS
Depth & Speed
Shower/hot water pump
Shower sump pump
Bilge pump
Will i need a horn?
240 offshore to two interior double sockets
Not too sure if i have missed anything here!?
 
emsworthy said:
I'm a bit mystified by this comment. I could understand if he said it would damage the power supply but as every laptop I can think of runs on somewhere between 12v-24v DC I don't see how the AC input to the power supply (transformer/rectifier) could possibly have an impact on the computer itself. :confused:

My laptop power supply runs happily off a modified square wave inverter (ie non-sine wave) and although the transformer makes some strange noises and runs a little hotter it has no effect on the lappie at all.
Click to expand...

To be honest, i am mystified by it all too, but like all subjects, there always seem to be many contrasting opinions.
Smoke & Fire in the shopkeepers comment?
 
Ahh....Also, a decent blow from our 240v hairdryer.
Those 12v hairdryers surely cant work that well.
You have me thinking that maybe i don't need an inverter after all.
Where would an inverter benefit me then?
Would it not charge my batteries when connected to offshore as well as giving me 240v when ime on me Gullivers?
 
Gelmaster said:
What if i am anchored with no offshore power available?
Will my laptop run off 12v? (somehow?) to play films!
Are there 12v DVD/TV's out there hiding away?
Click to expand...

You didn't have DVD & laptop in your list, or was that just a general fitting-out question?
 
Gelmaster said:
Ahh....Also, a decent blow from our 240v hairdryer.
Those 12v hairdryers surely cant work that well.
Click to expand...

hairdryer? troll?

Gelmaster said:
You have me thinking that maybe i don't need an inverter after all.
Where would an inverter benefit me then?
Would it not charge my batteries when connected to offshore
Click to expand...

no


Gelmaster said:
as well as giving me 240v when ime on me Gullivers?
Click to expand...

that's its purpose (but typically only for occasional devices, not for general use around the boat)
 
A non-sine-wave inverter did do in one laptop of mine. It went into spasm and then something in its guts stopped it ever taking power input up its charge hole again. I have no conclusive evidence that the wave form of the inverter was the problem.

When I plugged it in to the inverter the laptop itself made a horrible rattling sound, like a relay resonating (not like transformer hum). It then stopped for ever. It was an ancient laptop, and not worth investigating. I had previously run other laptops (yes plural) from the same inverter with no problem, but have been chary since.

I think it is possible that the actual problem was that the inverter was not capable of supplying ENOUGH power and was switching in and out, rather than the shape of the wave. I should have investigated this and done the arithmetic but I didn't.

Like others, I find it hard to believe that my 12v to 19v Maplin doofer is giving any cleaner DC - you should hear some of the noises it makes! It is, however, measurably more efficient than the inverter (by about a factor of two).

Even if it is clean, I would have thought that starting the engine (off the same 12V circuit) would put some pretty interesting transients into the system - but it appears to do no harm.

Superstition continues to stop me from plugging my brand new laptop into the inverter.
 
I seem to have only boring tasks at work today, so I'm prolific on the forums.
Gelmaster said:
Port & Star Nav lights
Bow and stern? do i need?
Steaming light
Mast top lighting
4x Small cockpit lights
10 "Led" cabin lights
2x shower lights.......i love my lights!
VHF
GPS
Depth & Speed
Shower/hot water pump
Shower sump pump
Bilge pump
Will i need a horn?
240 offshore to two interior double sockets
Not too sure if i have missed anything here!?
Click to expand...
Bow and stern?
Stern yes. Not sure what you mean by "bow". If it's a bicolour than you don't need port and starboard as well (unless you are big - can't remember the limit)

Steaming light yes

Mast top lighting
What does this mean? All round white for use as an anchor light? Then yes
You might want spreader lights to light the deck if necessary.

4x Small cockpit lights - I wouldn't - why bugger up your dark adaption. Keep a small torch in your pocket.

10 "Led" cabin lights - your taste
2x shower lights.......i love my lights! - your taste

VHF -yes
GPS - yes
Depth & Speed- yes
Shower/hot water pump - yes
Shower sump pump - yes
Bilge pump - yes
Will i need a horn? unless you have one that you blow or a gas cylinder one
240 offshore to two interior double sockets

Missing:

AIS - you'll end up with at least a receiver

Fluxgate compass probably at some stage

Autohelm certainly

Navtex?

Wind instrument?

At least two 12 volt sockets. Cigarette lighter type (horrible I know) to plug in car type phone charger, Maplin computer charger, etc. I also use rechargeable AA cells in all battery operated toys and charge them with a Maplin charger which plugs into 12 volt.

Battery monitor

Deck lights as mentioned above

Maybe a charger for a handheld VHF (it's handy to have a handheld for use on deck). I use rechargeable AAs in mine, so the ciggy socket does it.

Maybe a power supply to a handheld backup GPS.

Red light at nav station.

Possibly a charger for a searchlight/torch (steamer scarer). I have a very powerful torch which runs off a hefty dose of rechargeable AAs again.

These all arise from thinking about what is on my boat - which is tiny. My switch panel has 24 switches, of which about four are currently "spare". For some weird reason I like to have one switch for one appliance. Many people bundle things. For example an "instruments" switch switches on all navigation instruments.

Oh, and I forgot - I have a tricolour up the mast too.
 
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