How about inverters......

This is related to operating a laptop remotely to watch movies etc. So 2 to 4 hrs of operation. The battery in the laptop only gives me about 1.5 hrs max...so I will need to supply more power. What quality inverter do I need to go from 12v to 120ac in order to use the std computer home power unit. Or should I get a car cig lighter inverter. they cost 92 bucks. It seems that maybe if I need to get an inverter for 12vdc to 120vac anyways, that should be the way to go. I hope this is follow-able here.

The bottom line here is this: What quality inverter (12vdc to 120vac) do I need to run a laptop. Any suggestions?

Comments

  • Roderick
    Roderick Solar Expert Posts: 253 ✭✭
    Re: How about inverters......

    I believe the first thing a laptop power supply is going to do is rectify the AC into DC, then highly filter it, so it really doesn't matter what quality of inverter you use.

    A cigarette lighter inverter can be found for significantly less than $92, I would think. I see them on sale at Fry's (in California) for $15 - $20. That kind of inverter is probably inefficient, but a laptop is - what - 50 watts (?) so who cares. Also, I've had a car lighter inverter burn out after a few weeks - I don't think they're meant for continuous use.

    If you have 12V DC, you might look into whether there is an adapter that can power your laptop directly from that.
  • System2
    System2 Posts: 6,290 admin
    Re: How about inverters......

    Sorry....the cig lighter iverter for 92 bucks was a Fujitsu (laptop mfgr accessory) and it did go straight to the laptop.  That is probably the most efficient.....but like you said...who cares.  There are so many inverters sold these days...it's a b*tch to figure out which one to buy.  I guess my needs will be a 12dc to 120ac inverter that can handle 200 watts MAX for other stuff later....and I guess I don't need a "pure sine wave". I guess my biggest fear would be an inferior inverter screwing up my batteries or worse...the laptop.  I don't know if inverters can do damage. if they faulter.
  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: How about inverters......
    pmaru77 wrote:
    ..and I guess I don't need a "pure sine wave". I guess my biggest fear would be an inferior inverter screwing up my batteries or worse...the laptop. I don't know if inverters can do damage. if they faulter.

    It's a question of if the 120V - Laptop adapter/charger, can handle the square wave output by the inverter. The lightweight ones, that feel nearly empty, are transformerless, and * usually * do a better job with square wave inverters (I know, all the companies call them "modified sine wave" and it looks more like a square wave in actuality)
    The transformer type will often work, but run much hotter on the inverter (more losses in the transformer). If it runs fairly cool at home, it may work OK on the inverter. If it runs hot at home, I'd think about what a replacement would cost. Usually, when they die, they are supposed to fail OPEN, and not apply 120V to the DC output.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
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  • System2
    System2 Posts: 6,290 admin
    Re: How about inverters......

    Another thing to think about is the battery charging aspect of your laptop power supply. Many smaller chargers, as used with cordless power tools and I presume laptops, do not always work properly on modified square wave. They won't properly complete the charge and may even be damaged, as in smoke. Some of the problems (smoke) are caused by the sharp voltage changes at the corners of the square wave, which causes capacitors to "conduct" more current than the design called for, thus overloading other components, while other problems (not completing the charge) are a result of the lower overall peak voltage produced by the Modified Square Wave inverters, vs the RMS peak voltage of the pure sine inverters.. If you're only wanting to run the laptop, the MSW will likely do OK, but may not be OK for recharging the laptop battery.
    We've all heard about laptop batteries bursting into flames, but I don't know the exact cause.
    Good luck.
    Wayne
  • SolarJohn
    SolarJohn Solar Expert Posts: 202 ✭✭
    Re: How about inverters......

    For about a year I used an $85.00 modified sinewave inverter with my solar photovoltaic system. I was always afraid to plug stuff into it for fear that it may cause damage. I finally broke down and spent $574.00 for an 1100-watt true sine wave inverter, and I'm extremely pleased with it. My modified sine wave inverter put so much audio noise and streaks in the picture of a tv that it wasn't fun watching. Motors ran at the wrong speed, and it put noise over the audio on my radio.

    You don't need as big of an inveter as I bought. To just power your laptop you might find a good true sinewave inverter for a couple hundred bucks. It will be well worth the extra cost over a modified sine wave type.

    John
  • mwilsonnm
    mwilsonnm Solar Expert Posts: 26
    Re: How about inverters......

    You may want to consider buying a 12 volt power supply for your laptop. I use one for my Toshiba laptop and it plugs into a cigarette lighter type plug. The supply will convert the 12 volt to 120 for you. Mark
  • System2
    System2 Posts: 6,290 admin
    Re: How about inverters......
    mwilsonnm wrote:
    The supply will convert the 12 volt to 120 for you. Mark


    Hummm - that makes it an inverter.

    Wayne
  • System2
    System2 Posts: 6,290 admin
    Re: How about inverters......

    Why is the focus on going from dc-ac and then back to dc? Why not just go DC-DC?
  • Brock
    Brock Solar Expert Posts: 639 ✭✭✭✭
    Re: How about inverters......

    It depends on if yourn trying to run just the laptop or other misc 120vac items as well. If it were just the laptop I would just do a dc-dc conversion, but if you might need to run other loads as well, then go with a small inverter. I would double the size of the inverter you think you need though. Say you laptop calls for 100w, I would get a minimum of a 200w inverter.
    3kw solar PV, 4 LiFePO4 100a, xw 6048, Honda eu2000i, iota DLS-54-13, Tesla 3, Leaf, Volt, 4 ton horizontal geothermal, grid tied - Green Bay, WI
  • System2
    System2 Posts: 6,290 admin
    Re: How about inverters......

    i'm useing by lap top now with a xantrex 1000w inverter msw. don't need that much power but i haven't had any problems with it (yet). But it does beg another question... would you have problems running a 30" lcd tv with a msw inverter?? Pure sine and digital inverters are pricey but so is the tv i guess.
  • System2
    System2 Posts: 6,290 admin
    Re: How about inverters......
    bibion2 wrote:
    question... would you have problems running a 30" lcd tv with a msw inverter??


    That totally depends on how the power supply in the LCD TV was designed. If designed to handle almost anything thrown at it, which in my opinion it should be, you will have no problems. However, if the designers assumed that the TV would only ever receive top quality power and designed it for that, well, you could see some smoke if you run it longer than a minute or two on MSW.
    There is no simple yes or no answer. Sorry.
    Wayne
  • SolarJohn
    SolarJohn Solar Expert Posts: 202 ✭✭
    Re: How about inverters......
    would you have problems running a 30" lcd tv with a msw inverter??

    I used a small color tv with a msw inverter. the picture was streaky, and the sound had noise in it. These problems went away when I switched to a pure sine wave inverter. I wouldn't plug my expensive flat-panel tv into the msw inverter for fear of damage.

    John