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What a waste.


oldade

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Hi

Why are we using inverters to make 240 volts to power computers etc when the transformer in the computer etc is converting that back to 12 dc or less ?

What a waste of energy.

 

Shurely a 12 dc computer / video whould be best ?

Would it be easy to convert one to run of 12 volt ?

 

I hope the experts can answer this for me before I pull my computer in bits .

 

I know the laptop I have has a 14 volt battery in it so it should be easy to do.

 

Would it be best to charge the battery in the laptop from the domestic bank ?

How do we do it ?

It must use less juice doing it that way, plus we dont have to do anything to the laptop etc.

Are thyer inveters that have adjustable outputs ?

 

Thanks in advance.

ADE

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Hi

Why are we using inverters to make 240 volts to power computers etc when the transformer in the computer etc is converting that back to 12 dc or less ?

What a waste of energy.

 

Indeed. Daft.

 

Shurely a 12 dc computer / video whould be best ?

Would it be easy to convert one to run of 12 volt ?

 

No. A PC power supply is actually a very complicated piece of kit. Luckily someone has already done the work.....

 

http://www.powerstream.com/mini-itx.htm

 

A google will find a few more.

 

I hope the experts can answer this for me before I pull my computer in bits .

 

I know the laptop I have has a 14 volt battery in it so it should be easy to do.

 

Fraid not. It won't run from 12 volt. Even if you managed to persuade it to do so the slightest voltage spike (of which boats are full) would probably kill your whole laptop.

 

Adaptors are available to run typical 18 to 20 volt input laptops from car batteries.

 

Gibbo

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It always amazed me when I had to visit the local caravan/motorhome showrooms (ie, Brownhills & Lowdham Leisureworld) that they had these TV/DVD combos which ran off 12v at only £400, what's more it was a CRT TV too, so heavyish.

The price sticker was liberally sprinkled with the words "Only" and "Just" and "Bargain price of".

AND people paid it!!!

 

Go to most Supermarkets and you will find a DVD player for about £15, and a 15"LCD TV for around £120-150, both of which generally have 12v mains adaptors!!!

 

Silly!

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Sorry if this is a stupid question but how do we know if the output from the AC adapter is AC or DC volts?

 

The adapter for my laptop says 20v - 3.25 amps. Could I run this more efficiently direct (rather than via the inverter)?

Edited by blackrose
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Having just looked at my own adaptor, I suspect that between the 20V and the 3.25A will be straight line with a dotted line underneath. If so, I believe this means it is DC.

 

In this case you could run the laptop direct from a DC power supply, IF you have a 20V stabilised, spike-free DC power supply available. As the boat supply is likely to be either 12V or 24V, will not be stabilised and nothing like spike-free then you will probably still need an adaptor.

 

You can get adaptors to run laptops from either 12V or 24V supplies from the likes of Maplin, but whether they are any more efficient than using an inverter / mains adaptor I wouldn't know. If the only reason for having an inverter is to run the laptop, then a DC adaptor would probably make sense, but if you are have other 230V equipment that would need the inverter anyway, it's probably not worth bothering.

 

Just out of interest, what laptop do you use - mine's rated at 19V, 6.3A

 

Peter

Edited by Peter R
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I just cut the 12 volt lead off the 240 volt adaptor supplied and wired a 12 volt plug on it. It's run the lap top no problem as yet LOL The lap top accepts between 12 and 18 volts, I thought this wouldn't be a problem, but it seems I should use a correct adaptor which i assume would have some kind of gadget in line to protect the lap top, is that correct?

 

 

Just to add, I've done this with the TV DAB radio also :lol:

Edited by Julynian
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The adapter for my laptop says 20v - 3.25 amps. Could I run this more efficiently direct (rather than via the inverter)?
You can get adaptors to run laptops from either 12V or 24V supplies from the likes of Maplin, but whether they are any more efficient than using an inverter / mains adaptor I wouldn't know.

I use the a 120w adapter from Maplin for my laptop

http://www.maplin.co.uk/Module.aspx?TabID=...36&doy=14m6

 

My 240v psu gets very hot & the 12v psu from maplin stays cold,

i haven't measured the power saving, but the heat generated my 240v one is an obvious waste of power.

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I'm staggered by the power demands of many modern laptops.

 

I guess because they have a load more processing power and memory than older ones, they also take a lot more electrical power.

 

It seems manufacturers have managed to keep up with this greater demand by bigger and more efficient batteries, rather than by trying to reduce the power needed by the PC.

 

It's got to the stage where a laptop can represent a significant drain on boat batteries, if use is more than occasional.

 

If you only need it for internet, email, etc, it might be worth trying to acquire a model a few years old, that doesn't have a screen the size of a moderate TV.

 

Also most PCs have power saving modes where you can ramp back on processor speed, screen brightness, how long the disk spins after acccess, etc. etc. Tuning these can to some extent limit the power demands.

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I'm staggered by the power demands of many modern laptops.

 

Yes, I didn't realise how much power my new laptop would consume - about 4 amps on the inverter.

 

(It's a Fujitsu Siemens Amilo with 2GB ram running Vista)

Edited by blackrose
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Yes, I didn't realise how much power my new laptop would consume - about 4 amps on the inverter.

You are lucky if it's only 4 amps, (48 watts). Many are rated more like 120watts, (so 10 amps approx).

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Mine is about 40 watts plugged in & charging.

 

But each 30 min charge will last about 2 hours so I am getting 2 & 1/2 hours for each 1/2 hour at 40 watts. Thats only 16 watts per hour or 1.29 amps at 12.4 (half way between 12.6 fully charged & 12.2 my cut off) volts. Compared to a desk top pc & lcd screen at about 100 watts per hour its seems good value.

 

 

Justme

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The power ratings you see on laptop power supplies is not the typical current consumption.

 

It is the maximum power the laptop will use with the screen on full brightness, the processor rattling away as hard as it can, the hard disc running, the CD going at full belt and the charger running at full power charging up a flat laptop battery.

 

If you measure the typical current draw it is usually around 20% to 30% of the rating on the power supply. You can get this even lower by using the power management settings to automatically switch bits off when they aren't being used.

 

Gibbo

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I used a plug in power meter so could see the "live" wattage plus is will also track useage over time too. Very handy for working out just how much power YOU actualy use compared to the rating plates.

 

If I remember right the readings were :-

 

charging with laptop off 30w

charging with laptop on & in use 40w

power supply pluged in but laptop not pluged in 1 watt.

 

Justme

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The power ratings you see on laptop power supplies is not the typical current consumption.

Fair enough.....

 

I was genuinely surprised by what my son's one seemed to be using aboard.

 

It is an all bells and whistles one, with a screen more appropraite to a TV, and I don't imagine he has configured too many of the power saving options.

 

When I've more time, I'll try and get a better picture of what it's taking, and how much that can be improved still retaining reasonable performance.

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