Using laptop via 12v supply - help!

[snobbyafghan]

It would be handy to be able to use the laptop at places without hook-ups (aires etc). So, I can get an inverter and plug it into the 12v leisure battery. Is this OK? Two questions occur to me:

1 The laptop supply goes through a transformer which turns the AC into DC. So, if the laptop is actually connected to a DC supply, what's happening inside the transformer? Does it matter?

2. The transformer converts the mains supply to a DC current of 19v. Will it matter that the I would only be getting 12v from the leisure battery?

 

Thanks

 

Doug

[Andy T]

Hi,

You can use the laptop plugged into an inverter but the inverter takes about 10% of the supply current to run itself, so its not the most efficient way of doing it. You can buy a 12v to 19v converter to run the laptop from a cig lighter socket or din socket. Set the output to 19v and off you go. Look on Ebay or Maplin.

Look on the back of the laptop to see how many amps it needs and make sure the kit you buy can supply that or more.

Come to think of it the 12 to 19 volt converters get warm so they probably use a bit of current as well. Take your pick! And as a small laptop takes about 3.5amps, that around 40 watts, two spot light bulbs, don't flatten your battery!

Regards,

Andy.

[chatterdog]

for running my laptop (I stay on it for hours in chat) i use one of those battery charger/air compresser/jump starter things. plug the invertor into that and then connect my lappy. They only cost around £20 but can give about 30hrs use on my lappy without draining the leisure battery and to recharge it just plug it in to the ciggerette lighter socket when driving around

[Tony Jones]

I got a bit of kit which works fine for £50 from these people:

http://www.laptop-chargers.co.uk/dc.htm

 

It's listed as being for my (rather old) laptop, and looks just like the mains charger:

jack to go in back of computer, bit of wire, rectangular box with LED, another bit of wire, plug

but the plug is a "cig-lighter" one instead of a 13amp, and it presumably has different magic in the box.

 

Anyway my laptop runs happily on it, thinking (according to the "power monitor") that it's being fed AC power - and without any noticeable drain on the van's battery.

[alan k]

Yes I've just been thro this question having found the laptop didn't last very long on its own without hook up. Its also used as the DVD player as we've no tv.

 

So either

a small invertor, possibly the most inefficient way but also able to charge batteries for the cameras & run any low power 240v stuff,

or a transformer for the 12 to 19v but most are dedicated to laptop charging

 

So not having thought of the "powerpack" option which sounds a better idea I chose the small invertor, £19.99 from Maplins.

 

Pity this discusssion wasn't a week earlier! But the invertor works fine,

 

cheers alan

[zulurita]

Thanks for your info Tony Jones.

 

I have just emailed the company to see if they have a 12v adapter for my laptop.

[rowley]

If you do go the inverter route then it is worth paying that little bit more and getting a pure sine wave version.

Be careful though as one chap was selling one on ebay that included the words "pure sine" in the title. When I questioned him about it really being pure sine wave, it was not, he had just used the words to put keywords in the searches.

[libby]

I've been using a small converter that plugs into the 12v socket for a couple of years with no problem.

 

Title "ComOn" "Step-up DC/DC Converter for Notebook Computer" On the back is a variable setting indicator from 15v-24v in 7 stages. It also has a blade type 10amp fuse.

 

Cost was £12.00

 

LB

[trigrem]

 

Hi Zularita,

Perhaps this company can help, be careful to check on the compatibility link.

 

http://www.amperordirect.co.uk/products/Amperor_CPS-65DC.asp

I have been using one of their products for a number of years which gave a choice of various output voltages but they do not seem to list it, perhaps an e-mail to them giving your laptop details would help.

Doug

[Ventoux]

I bought a dedicated Compaq 12v cig lighter connection for mine on Ebay - £20. I found it eats battery juice quickly, so I just have it re-charging laptop as I drive, much better.

For internet I've been using the free wi-fi in McDonalds all over France. The good thing is they are all well signposted :-D . I don't even buy anything in there, nobody bothers me. If I can find a spare electric socket too thats a bonus

 

B-)

Interested in those £20 power packs, must investigate them when I return to UK.

[GJH]

Like chatterdog I use one of those battery charger/air compresser/jump starter power packs (bought from Aldi) to recharge the laptop battery when necessary. I connect using one of the 12v in, multi voltage out devices mentioned in some posts (bought on eBay).

 

Another factor which hasn't been mentioned but which is relevant is that battery life differs between laptops. When we bought our current one I deliberately asked the question and chose an Acer Aspire which has near enough 3 hours life from a full charge.

 

When not on hook-up I tend to use the machine only for e-mails rather than general surfing and forum access - but that has more to do with the fact that we are enjoying ourselves with friends so don't have time for surfing than anything else.

 

Graham

 

 

[zulurita]

Thanks trigem,

 

However I had already looked at laptop-chargers.co.uk and sent them an email giving all the details of my laptop eg 19v 4.74 A and laptop model code etc

 

They came back very promptly with the product code etc. I ordered it yesterdday morning and it arrived today before 09.00 so how is that for service :-D

[snobbyafghan]

Thanks for the input everyone - I've been in France since the original post and am only just catching up.

 

I wish I'd done something about this before I left the UK. I've got no problem with internet access - my Vodafone roaming dongle works well (much quicker than in the UK) but, if Im not on a site, my ability to communicate is poor because MY Acer Aspire battery only lasts 20 minutes at most. If only I had one of the various gadgets mentioned here.....!

 

Doug

[Tony Jones]

Acer Aspire is the make of mine Doug, so the people I linked to above (who Zulurita used as well) should be able to fix you up.

[GJH]

snobbyafghan - 2008-10-06 5:50 PM

MY Acer Aspire battery only lasts 20 minutes at most. If only I had one of the various gadgets mentioned here.....!

 

Doug

Doug, it could be that the battery is on its way out. Some laptop batteries, especially older types, can be very fickle about charging regimes. With some older batteries there was something termed (I think) the "memory effect" which resulted in batteries not holding a charge properly if they were charged before being (almost) fully drained.

 

I have an Acer Aspire 1203XV which is several years old and is only used on mains now as the battery refused to hold a charge.

 

I also have a newer Acer Aspire (5612ZWLMi, bought February 2007) which I use when we go away. Before I bought that one I asked in several shops about battery life because 2 to 3 hours was important for various reasons. I've also been careful about charging, allowing the battery to become pretty low before recharging.

 

So far it has behaved itself - but that could well be newer battery technology rather than anything I've done :-D

 

Graham

[snobbyafghan]

Graham

 

Interesting. Actually, I think I may have just got a duff battery on mine. It's never lasted longer than 20 minutes since I bought it (new).

 

Now I'm back in the UK, I'm going to chase down some of the suggestions here because if I could have used the laptop off the the 12v system, I could have used Aires even more than I actually did.

 

Doug

[neillking]

A duff battery can in some circumstances ruin a charger over time so you might want to replace that too. I give my laptop a fair old hammering and I've replaced the battery with a generic that I found at a good price on the web and that has been fine. The original mains charger works fine on a small inverter and also the Maplin 'Universal' Car charger works fine too - at a remakably good price. The worst products have been quite expensive Targus chargers (one 70w one 90w) both of which started to fail after about 18 months.

 

[snobbyafghan]

After reading this thread for about the 4th time, I still can't work out which system is best so I think I'll go with this inverter on offer for £19.99 at Maplins:

http://www.maplin.co.uk/Module.aspx?ModuleNo=218810

Seems s cheap option and should do what I want. What advantages are there in choosing one of the more expensive options?

 

Doug