anee Posted July 10, 2010 Share Posted July 10, 2010 We are planning a trip to northern france in a few weeks and our teenage daughter would like to take her laptop. Can anyone advise us (old fogies now) if its possible to use it on a 12V battery, if we can't access electrics, and what else would we need to use the internet? Any advice gratefully received! Link to comment Share on other sites More sharing options...
Guest Tracker Posted July 10, 2010 Share Posted July 10, 2010 Find out from the computer handbook if it has a socket for an external power source other than mains. This should also tell you the voltage it requires and from this infi it is easy enough to source a suitable adapter to work off 12v. My own Acer uses 18v and the adapter steps the power up from 12v to 18v and works just fine as well as keeping the internal battery topped up. If in doubt do nowt - and take it in to a proper computer shop for advice - it's better than buggering it up! Link to comment Share on other sites More sharing options...
camperadi Posted July 10, 2010 Share Posted July 10, 2010 Totally agree with tracker. My laptop is 20 volts and I use an adapter bought from ebay. If you not certain and you have a Maplins locally take it there. I am sure they will advise you and be able to provide the correct power unit for the job. Link to comment Share on other sites More sharing options...
flicka Posted July 10, 2010 Share Posted July 10, 2010 Hello Ann For Internet see the "Hints & Tips" section for "Internet on the move" But abroard any use of the web other than free wifi spots, by your own means, (mobilephone dongle or even worse dome system) will be expensive. Link to comment Share on other sites More sharing options...
spospe Posted July 10, 2010 Share Posted July 10, 2010 We use a small inverter to step the 12 volts DC up to 230 AC at 50 Hertz. This means that we can charge toothbrushes, camera batteries, shavers, insect repellent and run the laptop as if it were plugged into the mains at home. Our inverter model is only 80 watts and it is plenty for all the above. Link to comment Share on other sites More sharing options...
crinklystarfish Posted July 11, 2010 Share Posted July 11, 2010 I tend to agree with the small inverter route. They can be bought cheaply from many high street outlets and would allow you to use the standard laptop mains charger. The 12v ‘cigarette lighter’ chargers are slightly more efficient but you would have to be sure of the correct voltage requirements of the laptop and also ensure that the charger came with a tip (there is usually a choice of tips supplied) that would be compatible with you machine. If you do go this route, be aware some electronic equipment won’t work with some inverters so make sure you can take it back if it won’t power the laptop. Something like this should do it. Internet connection via laptop is not such a straightforward topic. There are many ways to get online but none are foolproof and, when abroad, some can be very expensive. I personally don’t rely on my laptop for internet abroad but do have my mobile phone set up to access email. Each mobile provider will have some or other product that allows such use, usually at a very reasonable cost. I’m making assumptions here, but if she has a decent phone and just wants to email and access social networking sites then the phone might be the solution. Her phone service provider would be able to advise how to go on. Link to comment Share on other sites More sharing options...
JohnP Posted July 11, 2010 Share Posted July 11, 2010 Some laptops will not run on an inverter unless it is the pure sine wave type. (Also applies to some TV's) Suggest a 12 volt adapter of which there are many around. Link to comment Share on other sites More sharing options...
ian81 Posted July 11, 2010 Share Posted July 11, 2010 To answer the other part of your query -access to the net in Northern France. 3G dongles whether from the UK or French bought are expensive. Wifi will be your best route and based on experience the 'Golden Arches' are the easiset to find / use and free. Link to comment Share on other sites More sharing options...
corkbuoy Posted July 11, 2010 Share Posted July 11, 2010 See here for 12 volt adaptor http://cgi.ebay.ie/ws/eBayISAPI.dll?ViewItem&item=250664245986&ssPageName=STRK:MEWAX:IT corkbuoy Link to comment Share on other sites More sharing options...
Brian Kirby Posted July 11, 2010 Share Posted July 11, 2010 If you look at the power adaptor for the laptop, you should find a label that will show the output voltage. Mine (Dell) is 19.5V. Any 12V powered adaptor has to convert 12V DC to AC to feed to a transformer, and then change the voltage to suit the computer. I have a variable voltage 12V converter, but it will not do 19.5V, so I only use the laptop on its battery, or when on mains. If the laptop is valuable, including the data on it, I would go the inverter route if you expect to be off mains hook ups a lot. For peace of mind, either check with the computer manufacturer if a pure sine wave inverter is necessary, or just get one to be safe. They cost a bit more but for just the computer, phone and camera battery chargers etc, one of the type that plugs into the cigar lighter should suffice, so shouldn't be that costly. Better that, than getting some cheapo 12V converter that fries its electronics because the voltage output is unstable. You should be able to get a car charger specific to the computer, but they aren't generally very good value.A teenage girl with a mobile phone abroad is liable to be very expensive, even if she only texts! :-)How bad that may get, will depend on the contract, how frequently she texts and whether she stays within the SMS limit. However, most contracts, and PAYGs, exclude roamed texts or calls from the free allocations. The freebies stop at Dover! Roamed calls are very costly. Texting is the cheapest option aside from using e-mail on a free WiFi hotspot.If she uses mobile internet at home, don't let her do so abroad. If roamed voice calls are expensive, roamed data use is extortionate!!Many campsites have free WiFi, and many more make a reasonable charge, but others have a huge sense of humour, or are just optimists! :-) The point is that nothing is certain, and she would have to accept that. As above Macdonalds allow WiFi use, generally in exchange for some purchase. Otherwise, look for the free campsite WiFi - not always freely advertised, and not always at the speed of light, and inclined to get slower the more people are using it. Oh, and don't be surprised if it suddenly terminates when they close reception! Link to comment Share on other sites More sharing options...
ian81 Posted July 11, 2010 Share Posted July 11, 2010 I agree with Brian re these cheap adapters -someone I know knocked the switch from 16V to 21.5. fortunately it didn't damage the laptop just fried the adapter. The best solution is to get a 'Kensington' power adapter such as Kensington Universal AC Car & Air Laptop Charger 33195EU. You specify a tip to plug into the laptop and the tip is responsible for setting the correct voltage. The unit works off 120 -240v as well as 12v and comes complete with an adapter to plug it in to the standardised socket on aircraft. This is a unit used by large businesses who value their IT equipment and means it is only necessary to carry one power supply. Personally I am in favour of straight 12v to appliance conversion -not going via 220/ 240 v as it is more efficient. Link to comment Share on other sites More sharing options...
crinklystarfish Posted July 12, 2010 Share Posted July 12, 2010 I too personally only use a DC-DC converter but the devil is in the detail with them. The 'Kensington', and very many others often do not come with the 'tip' required to enable them to be physically plugged into the laptop of choice. Also, as has been pointed out, if you get the supply voltage wrong on switcheable models, that funny melting plastic smell soon fills the 'van. For this particular questioner's actual needs, it probably isn't worth the hassle for the microscopic increase in efficiency. Also, if the laptop will run on a modified sine wave inverter, which most do, then neither is it worth, for this user, the expense of a pure sine wave jobbie. Link to comment Share on other sites More sharing options...
anee Posted July 12, 2010 Author Share Posted July 12, 2010 Thanks for all the replies, they have been very helpful. Now need to decide the best course of action. Will let you know..... Regards Link to comment Share on other sites More sharing options...
Guest Tracker Posted July 12, 2010 Share Posted July 12, 2010 Forgive my lack of understanding but as no laptops seem to work directly off of mains voltage as they all seem to reduce the 230 v ac down to whatever voltage they want dc, how does the mains transformer know whether the input ac voltage is pure or modified sine wave - and does the difference translate to affect the dc voltage it sends to the laptop - if that makes sense? Link to comment Share on other sites More sharing options...
Andy_C Posted July 12, 2010 Share Posted July 12, 2010 Tracker - 2010-07-12 12:47 PM Forgive my lack of understanding but as no laptops seem to work directly off of mains voltage as they all seem to reduce the 230 v ac down to whatever voltage they want dc, how does the mains transformer know whether the input ac voltage is pure or modified sine wave - and does the difference translate to affect the dc voltage it sends to the laptop - if that makes sense? It doesn't 'know' about a pure or modified sine wave input, it all depends on how well the electronics in the PSU can deal with it. I think most laptop PSUs deal with modified sine inputs quite happily, but may run a bit hotter than normal. The output voltage shouldn't be affected. I found this with my Dell PA-10 PSU, it worked fine from my old 150W modified sine inverter (before I got the right tip for my 12V adapter) but did get quite warm. Incidentally, regarding Brian's 19.5V Dell, mine is also 19.5V but it runs fine from my 12V adapter set at 19V Andy Link to comment Share on other sites More sharing options...
ian81 Posted July 12, 2010 Share Posted July 12, 2010 Tracker - 2010-07-12 1:47 PM Forgive my lack of understanding but as no laptops seem to work directly off of mains voltage as they all seem to reduce the 230 v ac down to whatever voltage they want dc, how does the mains transformer know whether the input ac voltage is pure or modified sine wave - and does the difference translate to affect the dc voltage it sends to the laptop - if that makes sense? Most modern electronics use a switched mode power supply rather than a transformer. Usually you can tell if this is the case as a SMPS will state an operating voltage fromm 90/ 110 up to 240v at 50 or 60Hz. These power supplies work by rectifying the ac voltage coming in to dc and then use electronics to turn the current flow on and off for a hugh frequency ac to a small inductor -this is done at a high frequency (50Khz to 500Khz). This inductor is like a small high frequency transformer that reduces the voltage to that required and then the hf ac is rectified back to dc. A similar mode of operation is used by 12v adapters -but instead of reducing voltage they increase. SMPS exist in many electronic items to turn the voltage coming in to the various voltages needed to run the item. EG for a desktop computer +-12v and 5v and 3.3v say. There is a similar arrangement in lcd screens / tvs as well. Sometimes an inverter which uses similar technology doesn't match up with the power supply -caused by harmonics or the frequencies internally of the two items interacting. Link to comment Share on other sites More sharing options...
AliB Posted July 12, 2010 Share Posted July 12, 2010 Tracker - 2010-07-12 12:47 PM Forgive my lack of understanding but as no laptops seem to work directly off of mains voltage as they all seem to reduce the 230 v ac down to whatever voltage they want dc, how does the mains transformer know whether the input ac voltage is pure or modified sine wave - and does the difference translate to affect the dc voltage it sends to the laptop - if that makes sense? Tracker, hope this helps. The main voltage is AC which means the voltage will alternate between positive and negative (+230 to -230). The voltage will change smoothly following the form of a sine wave. This smooth changing signal is then converted to a constant 19Volts DC (for example) to power the laptop. An inverter will take a 12V feed from the vehicle battery and convert this to 230V. A pure sine wave inverter will produce a steadily changing signal that is close in shape to that produced from the mains. Cheaper inverters produce an output of a series of stepped voltages that gradually rise from 0 to +230V and back down to -230V. This done 50 times per second. The laptop power supply is designed to expect a smooth changing power signal which it will convert into a fixed DC output (19V). The stepped input power signal can cause a non-constant DC output signal. Some laptops, or TV, do not like to run on a changing power signal. I seem to recall there was an article in MMM on this subject not so long ago. Link to comment Share on other sites More sharing options...
Guest Tracker Posted July 12, 2010 Share Posted July 12, 2010 Thanks AliB - but with respect that does not clarify what the 230v does, or needs to do, twixt leaving the inverter and arriving at the laptop? Thanks ian81 - but what does all that techy stuff mean regarding my original question about whether the ac mains input being pure or modified sine wave (and I do more or less know the difference) will have any effect on the dc output to the laptop? Link to comment Share on other sites More sharing options...
AliB Posted July 12, 2010 Share Posted July 12, 2010 OK, the 230V (now from the inverter) is fed into the laptop power supply. The laptop power supply will now attempt to convert the AC to DC and drop the voltage from 230V to 19V Because the 230V is not smooth but jumping around in steps the laptop power cannot convert this to a steady 19V. Hence the 19V output will be a "dirty" signal. If you put a dirty 230V signal into the laptop power supply you will get a dirty 19V signal out. Is that clearer? Link to comment Share on other sites More sharing options...
Guest Tracker Posted July 12, 2010 Share Posted July 12, 2010 Yup - absolutely crystal - thanks AliB! So, as I suspected, unless you have a pure sine wave 12v dc to 230v ac inverter you are better off with a 12v dc to 19v dc step up voltage adapter - well mini inverter I suppose - than a 230v ac to 19v dc adapter. Link to comment Share on other sites More sharing options...
ian81 Posted July 12, 2010 Share Posted July 12, 2010 Tracker - 2010-07-12 3:21 PM Thanks ian81 - but what does all that techy stuff mean regarding my original question about whether the ac mains input being pure or modified sine wave (and I do more or less know the difference) will have any effect on the dc output to the laptop?[ AliB - 2010-07-12 3:32 PM OK, the 230V (now from the inverter) is fed into the laptop power supply. The laptop power supply will now attempt to convert the AC to DC and drop the voltage from 230V to 19V Because the 230V is not smooth but jumping around in steps the laptop power cannot convert this to a steady 19V. Hence the 19V output will be a "dirty" signal. If you put a dirty 230V signal into the laptop power supply you will get a dirty 19V signal out. Is that clearer? Tracker most SMPS will not have a problem with either. AliB -what do you mean by 'dirty' ?-the whole joy of a smps is that it takes whatever is thrown at it and converts it to dc before 'playing around with it and pushing say 19v out. Link to comment Share on other sites More sharing options...
Guest Tracker Posted July 12, 2010 Share Posted July 12, 2010 Oh bugger - and just when I thought that I had grasped it all! Link to comment Share on other sites More sharing options...
flicka Posted July 12, 2010 Share Posted July 12, 2010 I'm with you on that, Tracker (?) (?) (?) (?) (?) >:-( Link to comment Share on other sites More sharing options...
AliB Posted July 13, 2010 Share Posted July 13, 2010 ian81 - 2010-07-12 4:10 PM AliB -what do you mean by 'dirty' ?-the whole joy of a smps is that it takes whatever is thrown at it and converts it to dc before 'playing around with it and pushing say 19v out. Your description of the operation of a switched mode power supply stated that harmonics can sometimes "fool" the power supply. As a quasi sine wave is really a square wave harmonics will be abundant. Yes, in theory a switched mode power supply will handle what ever is thrown at it. In practise it depends on the quality of the power supply. Laptop power supplies can have a short life even under normal operation which would tend to indicate they are not top quality items. A laptop does not draw a constant current due to the varying work load of the hard drive and graphics adapter. Hence, further increasing the work load on the power supply. The risk of using a quasi sinewave inverter may be small but a pure sinewave is a safer option. I admit I've used my laptop with a quasi sinewave inverter but people need to be aware of the issues and then decide for themselves. Link to comment Share on other sites More sharing options...
peterandlinda Posted July 13, 2010 Share Posted July 13, 2010 Hi To quote AliB, 'Laptop power supplies can have a short life even under normal operation which would tend to indicate they are not top quality items. ' We have a Kensington 12v to 19.5v power supply, bought through Dell for our XPS laptop and that lasted about 18 months before it stopped working. But we have ordered another one because they are reckoned to be the best match, even though they are not cheap. We almost expected the power unit to fail early because we very rarely use the laptop on anything other than the power unit and we are using something small that is essentiallly a transformer with wire coils and no cooling and it does (or it did) get hot when it was working. P&L Link to comment Share on other sites More sharing options...
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