# Running a laptop when not on EHU



## uncleswede (Apr 16, 2010)

Assuming I don't want to run a 12v input laptop charger from my engine battery via the cigarette lighter socket, is fitting an inverter the only sensible way to run/charge our laptops when not on EHU?

TIA

Rgds
CD


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## peedee (May 10, 2005)

Well I don't know of any other way! You will need a pure sine wave inverter though.

peedee


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## AndrewandShirley (Oct 13, 2007)

We have two ways that we charge our laptop up:

12v charger via our solar panel (during day time)

Take the lap top to a cafe / bar and charge it up whilst eating/drinking


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## Penquin (Oct 15, 2007)

Running an inverter uses MORE current from the battery as far as I know, you would be taking it from 12 to 240v, then down to 19v (which I think is what many laptops have as an input), there are losses at each stage of that process.

If you use a 12 to 19v charger the losses are reduced as there is only one link in the chain. I got a suitable one from Maplins for less than £20.

Each time you change the voltage some excess power is used to generate heat (that cannot be prevented) - hence why transformers get hot, so you are taking more out than you need.

The inverter also would need to be sufficiently powerful to cope with the start up surge - hence more than you need to run it once started.

I believe that is correct but am sure someone will correct my thinking if I am wrong. :lol: 

Dave


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## stevec195 (Jul 1, 2007)

We use the same method as penguin, uses less power than an inverter, although I am happy to be corrected.


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## wakk44 (Jun 15, 2006)

An inverter is my choice,I also have a couple of solar panels and 2 heavy duty leisure batteries so do not need an ehu.

There are other ways to recharge your batteries,a standard generator or an expensive gasperini automatic generator being other options.


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## wakk44 (Jun 15, 2006)

peedee said:


> ........... You will need a pure sine wave inverter though.
> 
> peedee


My netbook works fine with a modified sinewave inverter :wink:


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## Techno100 (May 8, 2010)

Mine did too Steve but I use a 12 volt one these days. Even my lowly netbook uses a 40 watt charger so is more efficient and the 17" samsung needed near double that 8O


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## Addie (Aug 5, 2008)

Can I ask why you don't want to use a 12v Laptop Charger?

I can understand if you are looking at some of the multi-tip and multi-voltage adapters available from Maplins and eBay. We've used this for years, but they seem to (physically) wear out over time.

More recently on eBay there are laptop specific totally sealed chargers with fixed voltage and tips, I've got 2 now and these are superb and have been in use every day (some times several times a day or all day) for 9 months. 

I have in the past used modified sine inverters which are fine but can sometimes cause Laptop power supplies to buzz, overheat and fail. I've experienced all three and it all depends how often you use it as to if you would have experienced this.

We're so happy with our 12v charger that we never bother getting the 240v one out of the box when we rarely have hook up.


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## Techno100 (May 8, 2010)

Always best to charge it in daylight too! why waste the excess solar charge.


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## spatz1 (May 19, 2011)

my old modified sine inverter made the mouse arrow jump around when charging on the toshiba nb2 , but the toshiba netbook was fine .... now fitted another modified and both are fine ... i measured the amps drawn while charging and it seems to pulse between 2 and 5a and is my bigest power drain..


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## Scattycat (Mar 29, 2011)

Probably like most vans, ours has 12v sockets that run off the leisure battery so we usually charge via one of these during daylight hours hoping that our solar panel keeps up with our charging requirements.

So far so good as they say :wink:


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## geraldandannie (Jun 4, 2006)

I know that, in theory, a direct 12C - 19V converter should be more efficient, but I sit firmly in he inverter camp.

We used to have a cheap Ebay 150W device, but that kept tripping out on my MacBook Pro. We bought a 300W unit from a show (£40), and it charges my computer without any problems. As a beneficial side effect, I also use it to charge Kindles, shaver, GPS, camera batteries, mobile phones - all using the mains chargers we got with the devices.

Gerald


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## mr2 (Feb 26, 2009)

wakk44 said:


> An inverter is my choice,I also have a couple of solar panels and 2 heavy duty leisure batteries so do not need an ehu.
> 
> There are other ways to recharge your batteries,a standard generator or an expensive gasperini automatic generator being other options.


Agree with above. We have a 130w solar panel plus 2 x 96Ah leisure batteries with 1800 inverter and use our laptops when off EHU


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## tulsehillboys (Jul 22, 2010)

Addie 
We are here again! 
12v charger all the way 
cheap - easily available on line 
no loopy conversions 

It is a bit like going to the states, exchanging pounds to euros to then buying dollars when you get there - desperately inefficient!!!!


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## uncleswede (Apr 16, 2010)

Addie said:


> Can I ask why you don't want to use a 12v Laptop Charger?


Hi.

One reason is that the only 12v outlets I have on my van are connected to the vehicle battery only and I'm worried about draining that (although we have a split-reg solar).

Also I've read about some reliability concerns with 12v chargers for HP dual-core laptops.

Cheers


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## uncleswede (Apr 16, 2010)

mr2 said:


> Agree with above. We have a 130w solar panel plus 2 x 96Ah leisure batteries with 1800 inverter and use our laptops when off EHU


Aah ... that's interesting as that more or less matches our set-up (130w solar plus 2x110Ah leisure batteries). Given that we'll have a laptop and a netbook (plus MP3 players, phones, Kindle) I'm edging towards a small inverter. I think I'll still get a 12v charger for the netbook however so we can charge that whilst driving.

Any other opinions/experiences re: running laptops, specifically, on _pure_ or _modified_ sine wave inverters?

Thanks to everyone that has responded so far 

Rgds
CD


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## jedi (Nov 22, 2007)

400w modified sine inverter, 2 x 110 ah batteries.

Use extensively with my laptop with no problems. Spend maybe 2 -3 hours on line each evening this way over 3 - 4 days parked up. Batteries cope comfortably with this. So unless you intend to surf the net all night and not drive for days don't worry.

However, reading this thread, I may also try the 12v option as I'm always open to different ways of doing things :wink: 

Jed


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## jhelm (Feb 9, 2008)

We run our laptop all the time on a modified sine wave inverter, that is the cheap kind. It's 600 watts. I have a shortened extension chord attached to it with 5 outlets and we charge all our stuff off of it and run the dvd player. We use the laptop also for navigation when driving so it is on a lot.


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## Oscarmax (Mar 3, 2011)

Addie said:


> Can I ask why you don't want to use a 12v Laptop Charger?
> 
> I can understand if you are looking at some of the multi-tip and multi-voltage adapters available from Maplins and eBay. We've used this for years, but they seem to (physically) wear out over time.
> 
> ...


Hi following the above I brought one for HP laptop £8.95 inc postage on ebay


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## jhelm (Feb 9, 2008)

Oscarmax said:


> Addie said:
> 
> 
> > Can I ask why you don't want to use a 12v Laptop Charger?
> ...


Three cell phones, tablet computer, laptop computer, dvd player, 2 camera batteries = 8 12v chargers or one inverter.


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## bigtwin (May 24, 2008)

jhelm said:


> Three cell phones, tablet computer, laptop computer, dvd player, 2 camera batteries = 8 12v chargers or one inverter.


Exactly! While the efficiency arguments (conversion losses) mentioned in other posts are true (although, in reality, are insignificant), there are other reasons to support the inverter case.

As has been recognised in many other threads, where there are weight (or space) limitations, any item that has more than one use (or can be used by more than one device!), is easier to justify a space for!!


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