Guest Posted November 30, 2011 Share Posted November 30, 2011 ok, so I'm going to do a bit of cruising over summer and need to take a couple of laptops with me - netbook for nav and my work laptop that has all the stuff I need to do a bit of work every day via vodafone connection. Question is - am I better to buy bespoke 12v chargers for them both (different voltages) or just invest in a smallish inverter to step up to the 240v chargers and charge from there. Power is not so much of a concern, the solar and a very techie regulator keeps that up but what is the deal with losses stepping up to 240v then back down to say 19v for one of the chargers? Wheels - any idea? Is that an efficient way to make it happen or better to spend the couple of hundred bucks to buy the bespoke chargers? Link to post Share on other sites
Farrari 4 Posted November 30, 2011 Share Posted November 30, 2011 I have a generic 12v-19v dc:dc inverter for charging my laptop. It has a number of different tips and a selectable output voltages. It is much more efficient than using a 230v inverter. From memory I got it from Dick Smith for approx $100 but next time I'm down on the boat I'll get the model number if you are interested. Link to post Share on other sites
Changed 10 Posted November 30, 2011 Share Posted November 30, 2011 I just use the 12 volt cigarette plugged charger that came with the LT. Efficient and easy to manage. Have never used it for sustained long-term running though. Link to post Share on other sites
Fogg 427 Posted November 30, 2011 Share Posted November 30, 2011 I went the bespoke route i.e. 12V to 17-19V for my HP laptop. Partly for losses but mainly to avoid having mains voltage anywhere on my boat. Link to post Share on other sites
Guest Posted November 30, 2011 Share Posted November 30, 2011 hmmm - seems to be familiar theme developing here! Looks like it might be the bespoke version for all the reasons I thought... Cheers Guys. EE Link to post Share on other sites
tuffyluffy 76 Posted November 30, 2011 Share Posted November 30, 2011 Im in the same boat as the guys above. Bought a 12v cigarette charger for an HP laptop on Trademe - $30 IIRC Link to post Share on other sites
Fusion 0 Posted November 30, 2011 Share Posted November 30, 2011 Lind is the product http://www.lindelectronics.com/ Link to post Share on other sites
Fogg 427 Posted December 1, 2011 Share Posted December 1, 2011 Lind is the product http://www.lindelectronics.com/ Can you still supply these, Fusion? If so, can you get Mac extension leads or do they run direct of ciggie lighters? Link to post Share on other sites
John B 106 Posted December 1, 2011 Share Posted December 1, 2011 Taking this for what its worth , IE from someone with a total electrical/ electronic knowledge of don't let the red wire touch the black one, I'm told that all inverters are not created equal and that some will not charge some laptops. Something about sine waves IIRC. Link to post Share on other sites
Absolution 7 Posted December 1, 2011 Share Posted December 1, 2011 I got one from PBtech although it looks like they are out of stock. Works great! http://www.pbtech.co.nz/index.php?z=p&p=NBATAU8040 Link to post Share on other sites
Farrari 4 Posted December 1, 2011 Share Posted December 1, 2011 Taking this for what its worth , IE from someone with a total electrical/ electronic knowledge of don't let the red wire touch the black one, I'm told that all inverters are not created equal and that some will not charge some laptops. Something about sine waves IIRC. John, that only applies to DC to AC inverters. The ones we are talking about here are DC to DC specifically designed for charging laptops from a cigarette lighter. FYI You are right with the DC to AC inverters in that some produce an approximate sine wave that looks a little more like a square wave and some/most electronic equipment doesn't like this. See the picture below. Link to post Share on other sites
John B 106 Posted December 1, 2011 Share Posted December 1, 2011 Thanks Farrari, I'll attempt to lock that information in. Inverter=curve good, square bad. Link to post Share on other sites
Fogg 427 Posted December 1, 2011 Share Posted December 1, 2011 FYI You are right with the DC to AC inverters in that some produce an approximate sine wave that looks a little more like a square wave and some/most electronic equipment doesn't like this. See the picture below. How do you know which is which? I doubt they put a pic like that in the brochure esp if it's that bad! Link to post Share on other sites
wheels 543 Posted December 1, 2011 Share Posted December 1, 2011 Square wave is better known as "Modified Sine Wave". They are not exactly square wave, but stepped Square wave. The number of steps used to make the Square look more like a sine is what sets the expensive inverters apart from the cheapies and why a pure sine wave inverter is expensive. A good Modified sine wave inverter can run most equipment these days, p[lus most electronic equipment have a SMP or Switch Mode Power supply to drive them. This is because an SMP is able to automaticaly run on any voltage and frequency and thus electronics can all be made the same for world wide shipping, which saves costs. All laptop power supplies are SMP devices and will run on pretty much anything. A good rule of electrics to keep in mind is that when ever you change power from one Voltage to another, you will get a loss. How much of a loss does depend on the circuit and it's quality, but you can usually bet on about an 80% efficiency for an Inverter. Some Laptop PS's are very inefficient. You just have to put your hand on the thing and feel the heat. The heat is the wasted power. I have never run a laptop from a 12V source, but as it has to take DC, turn it into AC, upscale it, then turn it back to DC, it is probably not a lot different to plugging into an inverter, which is taking DC, turning it into AC, upscaling it, supp[lying your Laptop Power supply which then turns it into DC, downscales it and then feeds the laptop. Link to post Share on other sites
Guest Posted December 1, 2011 Share Posted December 1, 2011 Thanks Farrari, I'll attempt to lock that information in. Inverter=curve good, square bad. 99% of the ones I've seen are called 'Inverters' or 'Pure sine wave inverters' so it's pretty easy to tell which is which. You can also tell by price, pure sine wave are usually a lot more expensive. In the sussing of D1's micro eco-dwelling, being solar powered, a lot of the info did suggest that electrical equipment i.e. flat screens, computers and the like, are far far happier and safer on pure sine wave than just the std option. But I have also been told recently that much of that equipment is now coming out with something technical worded built in. That whatever it is make the gear fine on std inverters. How this relates to AC/DC I don't really know so be-careful or you may Blow up your Video at The Flick of a Switch which would be a total Ballbreaker possibly due to High Voltage. If you did that you probably would be on The Razors edge and need a Stiff upper lip or maybe some Black Ice and most likely someone who could do Dirty Deeds done dirt cheap. I wouldn't want to be a Fly on the Wall when you did that so I'd slide Back in Black or jump on the Highway to hell instead Yeap, couldn't hep myself Link to post Share on other sites
Island Time 1,239 Posted December 1, 2011 Share Posted December 1, 2011 OK guys, here is the deal. If you use your standard laptop power (mains) adapter with a inverter from your 12v system you are wasting power. Sometimes a lot (in the region of 40%) Buy a good 12v laptop supply (Belkin are good). The best ones will do almost any laptop, and switch voltage when required, often automatically. I do this, and in one case I've seen, the current draw for the laptop went from 4.5a (12v, DC) down to 2.2a! That is a lot.... The cheap ones are often pretty inefficient. It is ALLWAYS inefficient to go 12-230-18v or whatever... Modified sine wave inverters are cheap, but often won't run appliances. esp microwaves and TV's, although new LCD or LED tv's are better. Link to post Share on other sites
hphcrew 0 Posted December 1, 2011 Share Posted December 1, 2011 This is the $ 35.00 12V LapTop charger I'm using on my Yacht:http://admiral.net.nz/shopping/pgm-more_information.php?id=7&=SID (It will work as long as the LapTop plug is industrial standard) Link to post Share on other sites
PaulR 3 Posted December 1, 2011 Share Posted December 1, 2011 good to see you get at least 8 "standard" adapters for your laptop "SOCKET" knot a plug IMHO. Thanks for all the good info. Link to post Share on other sites
NevP 0 Posted December 1, 2011 Share Posted December 1, 2011 So what happens to your laptop if you set the wrong voltage or attach the adapter plug around the wrong way so that it has a -ve centre pin instead of +ve (or vice versa)? Puff of smoke and dead laptop? Or is there some sort of protection circuit in the laptop? I'm sure if it was me it would be bound to happen at least once. Link to post Share on other sites
hphcrew 0 Posted December 2, 2011 Share Posted December 2, 2011 I did not find it to difficult to set the Volatage (the details are on the LapTop's 220V power adapter)... and if the plug fits than that is it..... Link to post Share on other sites
Recommended Posts
Archived
This topic is now archived and is closed to further replies.