Laptop power??

chockswahay

Member
Joined
13 Jul 2003
Messages
249
Location
Cornwall (eventually)
Visit site
Hi all, just a quick question (could search but in library and nearly out of time on 'puter).

I have just bought a new laptop and my question is this. Can it be ran from my onboard 12v ring or will I need invertor? I say this coz the little mains transformer says 19.5v output.

All advice much appreciated as always

Cheers

Chox
 

Trintella

Member
Joined
29 Jan 2004
Messages
77
Location
Gloucestershire
Visit site
You've got 2 basic options:

1) get a car laptop adaptor (plenty on e-bay) that has adjustable output voltage & polarity (be very careful to check the polarity before connecting it to a laptop - I recently didn't and blew a system board); or

2) you could get an AC step up adaptor - I used one last year but felt that it drained too much power - ie. you step up, plug in a mains plug, and then step back down with the normal laptop adapator
 

Swagman

New member
Joined
1 Feb 2005
Messages
1,444
Location
Based from the UK, try to get away on a boat for a
www.sailblogs.com
Think you'll find lots of past posts on this and I'm sure they will now be repeated all over again.

Yes - you can drive the laptop direct 12 v to 12v and it will work and not harm the laptop, but it will not be sufficient to charge the battery in a reasonably short period .
Or you could search the web for Laptop Power supplies and you'll find lot's of devices which will take 12v from a cigarette lighter socket and boot it to 19 / 19.5v.
I got one last week cost cira £37 - works on boat or in car just fine - and cheaper / smaller than an inverter.
Cheers
JOHN
 

robind

New member
Joined
23 Jul 2003
Messages
1,568
Location
sussex
Visit site
Try Maplin they do a 12 to 24 volt dc adapter that can be set at all the levels in between. and a 12 volt dc down to what ever you want too. they also have a good selection of plugs as a standard part of the kit too
Best of luck
Rob
 

Steve Clayton

New member
Joined
22 May 2003
Messages
7,478
Location
Benitachell - Spain
www.aloeland.co.uk
Nah!!!, Chocksy lives in Wales. Surely Maplin's aren't in Wales yet? /forums/images/graemlins/laugh.gif Get the 12 to 19.5v thingy converter on e-bay cos it's a lot cheaper.

Got to go; it's time for another Bacardi /forums/images/graemlins/wink.gif
 

Swagman

New member
Joined
1 Feb 2005
Messages
1,444
Location
Based from the UK, try to get away on a boat for a
www.sailblogs.com
Hi Steve / Liz

[ QUOTE ]
This is what you want (and soooooo cheap on "buy it now)":

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?V...ssPageName=WDVW

I've got one and it runs, cahrges (sorry, too much Bacardi!) the battery with no problems

and "Swagman"; Come on John (and Sue); surely you've got no time for this with RP kicking off in 3 weeks time!!!

[/ QUOTE ]

Hi Steve,

Yup - seems sad cases like us - whether in UK or Spain - still while away the hours on this site!

We'll be stopping over for a few nights in Denia circa July 1st - PM your local number and we'll call to catch up.

Cheers
JOHN
 
A

Anonymous

Guest
I've just blown up the motherboard on my laptop by transmitting on the SSB radio while the laptop was connected via a 12V converter. Fortunately I was insured and it was fixed immediately I got back into harbour and fortunately I don't use the laptop for real time nav! If you have an SSB radio, don't transmit when the laptop is being charged; let it run on internal batteries during the transmission period. I forgot /forums/images/graemlins/frown.gif
 
A

Anonymous

Guest
[ QUOTE ]
You can assume that it is a certainty that you have something wrong with your ssb installation.

[/ QUOTE ]Good grief, that's a bold statement given that you have so little information to go on! As an electronics engineer and a radio amateur I can tell you that the installation (which was carried out professionally) seems fine and the radio performs excellently. The radio does not interfere with any other equipment on board other than the instrument panel LEDs which tend to light up when transmitting, a common, indeed almost normal phenomenon.

The cheap dc to dc converter is designed to provide a range of voltages selectable from a rotary switch on the box; my laptop requires 18V but the unit is designed to provide much higher outputs (it isn't to hand as I write but I think in excess of 30V). When I get around to checking out what actually went wrong I suspect we will find that the output flies up very high when I transmit.

150W is a lot of radiated power and, as every radio amateur knows, one must be very careful about suppression of nearby electrical equipment that might be susceptible to RFI.
 

Ships_Cat

New member
Joined
7 Sep 2004
Messages
4,178
Visit site
What a dismissing outburst.

I suspect we will find that the output flies up very high when I transmit.

And I wonder what causes that - fairies? As I am sure you know it will be rf.

...the instrument panel LEDs which tend to light up when transmitting, a common, indeed almost normal phenomenon.

That is not ...almost normal, if it happens then there is a problem (none of my LED's light up even at 500-600 watts).

You mention ...as every amateur knows... well you may like to consider 1kW field day and dxexpedition stations directly in the field of the antenna - are you telling me that they have to keep their computers and other electronics down the street some place out of harms way.

On board I have run 600 watts with computers powered by jump converters or inverter connected to the radio with computer and transmitter within a few meters of the antenna. My normal installation is a 150 watt transceiver connected to a computer (for various digital modes, etc) powered by a jump converter and have no issues with that at all - the ATU and bottom of the antenna is located approximately 2m from the chart table where the radio, computer, switchboard, instruments are located - and that is what any installation should achieve.

In any event if you are prepared to dismiss my comment so readily without seeking any reasons for my comment then you are a foolish man. But it is your computer, so do as you wish - maybe it will be one/some of your instruments next. It does not happen on a good installation and I can assure you that I know what I am talking about, it is obvious that you do not.

As you are quoting qualifications trying to place some merit on your dismissal of my comment perhaps I need to add that I have a university degree in electronics and classical physics (electromagnetic and other fields), am a radio amateur, and have managed many telecommunications projects both on land and sea. I specify the radio installations for the boats I manage the design and build of and many others specifically seek advice from me regarding such installations.

I suggest that you sort your own problem out.

John
 
A

Anonymous

Guest
[ QUOTE ]
What a dismissing outburst.

[/ QUOTE ] You've taken a university degree in electronics in the last six months, since we had a similar exchange? Last time you were waffling about "university level", whatever that means. No educated technical person would claim that anything was a 'certainty', especially when they have virtually no facts whatsoever - go back to the information you were given. Almost anything could possibly have caused the problem from the information I posted. No engineer, technician or scientifically-trained person would dream of making the sort of pronouncements that you come up with. One must be very careful with electronic and electrical equipment that is operated in the vicinity of high power rf. That is fact and common knowledge to everyone in the field. What is it with you???
 

Ships_Cat

New member
Joined
7 Sep 2004
Messages
4,178
Visit site
I did indeed in some other exchange, one where you started quoting your qualifications at me, refer to my having "university level" qualifications in response. I suspect that most are aware that a "university degree" is in fact a "university level" qualification even if you do not /forums/images/graemlins/crazy.gif.

If you think 150 watts on a boat is "high power rf" then you are in for a surprise. I can assure you that such a station is a tiddler in the wider scheme of things in the HF world. 150 watts on a boat is of no issue at all - provided that you know what you are doing.

The fact is that PC's with step up power supplies are very commonly used on pleasure boats with no problems whatsoever from rf. So it is redundant for you to provide advice that buck converters (or in fact any other switch mode power supply such as is to be found in the radio and computer themselves if 230v powered as they may be) should always be disconnected from a computer when a radio is used on a boat.

Seems that you hate cats that know what they are talking about so I will move on.

John
 

Oldhand

New member
Joined
21 Feb 2002
Messages
1,805
Location
UK, S.Coast
Visit site

Ships_Cat

New member
Joined
7 Sep 2004
Messages
4,178
Visit site
I normally use a Vanson one on the boat - I understand that these are also available in the UK and are cheap.

Being switch mode type devices these converters can create noise in radio receivers, especially a sensitive radio connected to the computer for weather fax etc. Most have ferrite chokes on the leads each side of the device (can be seen in Oldhand's link) but if noise is a problem adding a large clip on ferrite cube on the long cable side as close to the existing choke as possible attenuates the noise. Normally need a cube big enough to get 4 turns of the cable through and it pays to pull the cube tight closed with a cable tie, instead of just relying on the clip, so that the flux path through the cube is not broken. (The cubes can be bought from most electronics outlets in all countries).

John
 
A

Anonymous

Guest
[ QUOTE ]
If you think 150 watts on a boat is "high power rf" then you are in for a surprise. I can assure you that such a station is a tiddler in the wider scheme of things in the HF world. 150 watts on a boat is of no issue at all - provided that you know what you are doing.

[/ QUOTE ]It has absolutely nothing to do with 'knowing what you are doing'. It is all about the field strength at a given distance from a radiating antenna. As you are no doubt aware, the field strength in Volts per metre falls off by the inverse square law as you move away from the antenna. Within a few boat lengths the field strength is quite high. Whether or not this will affect any electronic equipment is nothing to do with the installation of the transceiver. It is down to the design and construction of the piece of electronics in question. Marine electronics and well-designed computer parts are designed and tested to have a high immunity to RFI but cheap things imported from goodness knows where might not. Anything with long wires attached should have evidence of ferrites on the leads (as you will see on all computers, TV/video and digital camera parts).

My dc dc converter is very cheap in construction and there is no external evidence of any suppression (you would expect a ferrite on the leads at the very least). I have serious doubts about any of the cheap laptop supplies that are available and would remind those reading this that even if they don't have an SSB transmitter, they might be tied up alongside someone who has!!

I lost my mother board and I am fairly sure that this was the cause. My only motive in continuing to post on this matter is to try to forewarn others of the very real risk. Until last week, I had not had a serious computer crash for years and I can say that it was an unnerving experience, with the worry about loss of data, configuration, software, etc.
 

Ships_Cat

New member
Joined
7 Sep 2004
Messages
4,178
Visit site
For goodness sakes Lemain this is getting tiresome. Where did I refer to ...the installation of the transceiver.?

I actually referred to ...something wrong with your ssb installation. Claiming yourself as a elctronics qualified type person you would hopefully understand that to be a systems approach to the whole installation including the ATU, the power supplies, the cabling and transmission lines, the antenna, and the rfi proofing of the boat's electrical and intrumentation systems. But I should add, that the installation of the transceiver can, despite your claim otherwise, cause the problems you faced. Furthermore, problems inside the transceiver can also do so. So it is not just the radiated field that is an issue to be considered.

You are also up the creek on the ferrites such as those installed by OEM's on computer equipment, etc providing protection. But I will not go into that for the sake of avoiding a tedious response. I only mention it so others should be warned that such ferrites commonly installed on such equipment cannot be relied upon to provide protection and are, in fact, not put on them for that purpose.

Seems that you are on the wrong track on every front doesn't it? Doesn't pay to pursue arguments with those who have a particular expertise that you do not have yourself.

John
 
A

Anonymous

Guest
[ QUOTE ]
I actually referred to ...something wrong with your ssb installation.

[/ QUOTE ]There doesn't NEED to be anything wrong with the installation or the components to explain why something like a dc dc converter can give an excessive output when used near to a transmitting antenna. Not many 12V laptop supplies will have been designed or tested with this in mind; the majority will be intended for cars, trucks, and RVs.

[ QUOTE ]
But I should add, that the installation of the transceiver can, despite your claim otherwise, cause the problems you faced. Furthermore, problems inside the transceiver can also do so. So it is not just the radiated field that is an issue to be considered.

[/ QUOTE ]I have never said otherwise. However one would not immediately suspect a faulty installation/system when a perfectly simple and obvious explanation is to hand. My radio works brilliantly and does not intererere with anything else on board. Yet you claimed that a faulty installation was certainly the cause of the problem. Very strange!!

[ QUOTE ]
You are also up the creek on the ferrites such as those installed by OEM's on computer equipment, etc providing protection. But I will not go into that for the sake of avoiding a tedious response

[/ QUOTE ]Any response from you will be tedious so at least we can agree on something. But you are wrong on this point. Ferrites are added to make the equipment comply with RFI EMC standards and these cover immunity to external fields and lack of interference generated by the equipment itself. Ferrites can help in both cases.

[ QUOTE ]
I only mention it so others should be warned that such ferrites commonly installed on such equipment cannot be relied upon to provide protection and are, in fact, not put on them for that purpose.

[/ QUOTE ]Now you seem to be agreeing with me in advising people to beware in the vicinity of transmitting antennae.
 
Top