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| Thread ID: 58961 | 2005-06-17 09:50:00 | Laptops, invertors, generators, batteries etc | Andrew B (867) | PC World Chat |
| Post ID | Timestamp | Content | User | ||
| 364579 | 2005-06-17 09:50:00 | If I want to use my Compac laptop computer for longer than the laptop battery will last, can I safely use it on a 12v/240v invertor? Is a modifed sinewave invertor suitable, or is a true sinewave one better? What is the difference? The power supply for the laptop is labled: input 100-240v 2.4A output 18.5v 4.9A. Does this mean that the invertor needs to be rated at more than 576 watts (240 x 2.4) ? And looking at invertor specs on DSE website, a 300w invertor draws 28 amps at full load, therefore i guess a 600w one would draw nearly 60 amps. How do I work out the capacity of 12 v battery needed to say watch a dvd on the laptop? And how long would a small generator that rated at 7 A 14.4V output take to recharge the battery? I guess the simple answer is don't take the laptop when you go camping. But hey what if it rains all weekend and we just want sit in the caravan and watch a dvd? | Andrew B (867) | ||
| 364580 | 2005-06-17 10:04:00 | The laptop inverter will be happy on any dirty AC waveform, it converts it to DC and then high speed switches it. It really will not care. The rating needed is not 2.4 amps at 240 volts, the current stated is the highest drawn (100 v) so its really 240 watts. But I happily run an identically rated laptop supply on a 100 watt inverter. 18.5 v at 4.9 amps is only 90 watts output, plus a bit for the losses in the adapter. But the laptop seldom ever draws 4.9 amps so the average is probably more like 70 watts. Thats realistically about 100-120 watts input or 10 amps. A standard 47 Amp-Hour car battery would deliver about half of that 47 AH capacity into such a load, so you would get roughly around half an hour or less at 60 amps/720 watts. But flattening (deep cycling) and recharging a standard car battery will kill it in just a few charge-discharge cycles. You need a deep cycle battery for that. 7 amps charge would take 47/7 = about 7 or 8 hours, plus another couple of hours to overcome losses etc to recharge. Say 10 - 12 hours. |
godfather (25) | ||
| 364581 | 2005-06-17 10:33:00 | Thanks, GF, for your informative reply. So it looks like i need a deepcycle battery that will deliver 10 amps for 2 or 3 hours, that's going be expensive just to use the laptop. A lot more than a setup to run some 12v florescent lights for the evening anyway. And i guess that running the laptop directly off the 240v output of the generator is not going to be wise, when the generator instruction book says don't use it for computerized products and voltage fluctuations will occur at various times when loads change. And who wants to listen to a generator all evening anyway. | Andrew B (867) | ||
| 364582 | 2005-06-17 11:31:00 | Mate of mine is an independant power enthusiast. Goes through Godknowswhat complications with his comp and his food processor et al maybe you can email him at stupot222@yahoo.com. Like, seriously, he has lots of experience of this sort of thing. {Edit gee stu you get barrow loads of spam coz of this tip it on me dude.} |
mark c (247) | ||
| 364583 | 2005-06-17 11:41:00 | Become a Luddite. | godfather (25) | ||
| 364584 | 2005-06-17 12:09:00 | How much fun does a Luddite have? | Andrew B (867) | ||
| 364585 | 2005-06-17 12:43:00 | Odd post from you, GF. oh much honoured and appreciated poster here @ Pressf1. Independent power has nothing to do with Ludditism -exactly the opposite. The current power generation and distribution is Victorian technology. Enormously wastefull and inefficient. Independent power is the way of the future but what I say to my pro-indedendent power enthusiast friends is that the future is too slow in getting here, That's all.......m [Edit : That's why after 15 yrs on solar panels and batteries I have defected to the mains.] |
mark c (247) | ||
| 364586 | 2005-06-17 23:11:00 | Odd post from you, GF. The suggestion to become a luddite was directed to Andrew, to save him the angst of trying to power all those devices when he should be enjoying nature, unencumbered by technology. It has nothng to do with RAPS systems of which I am very familiar, and closely involved with in a regulatory aspect. www.luddite.com |
godfather (25) | ||
| 364587 | 2005-06-17 23:32:00 | Oh OK Right :) | mark c (247) | ||
| 364588 | 2005-06-18 03:05:00 | Why not run it off 230V? There are petrol generators (Chinese copies of Honda ones) selling for ridiculously low prices ($129 at Bunnings). They are nice and quiet (quite unlike the old Briggs and Stratton engined ones, though still not as good as the Panasonic one I "only just" heard a while ago). An 18m power cord and a simple shelter to keep the rain off it and you can watch your DVDs for hours. |
Graham L (2) | ||
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