Laptop om 12 volts

Discussion in 'Computers' started by Figaro, Feb 24, 2018.

  1. Figaro

    Figaro Funster

    Joined:
    Feb 22, 2011
    Messages:
    2,123
    Location:
    Newcastle under Lyme Staffordshire
    Ratings:
    +2,704
    I recently bought an adapter to up the 12 v to 19 v required by the laptop and have it plugged into a Hella socket, all works fine. I then bought an extension lead so I can position the lappy where I need it.
    It lights up the battery light ok but shuts down a couple of seconds after switching on, I should add the lappy battery is knackered so it needs the external power source.
    Seems like there is insufficient power getting to it with the extension lead ?
    Does anyone know a why the extension lead seems to loose this much power to stop it working ?
    Edit, extension lead is about 2 metres
     
    Last edited: Feb 24, 2018
  2. vin0114

    vin0114 Funster

    Joined:
    Feb 8, 2014
    Messages:
    1,200
    Location:
    Sheffield
    Ratings:
    +1,570
    Maybe the extension lead is not heavy enough so a voltage drop may be the problem?
     
    • Thanks Thanks x 1
  3. pappajohn

    pappajohn Funster Life Member

    Joined:
    Aug 26, 2007
    Messages:
    33,498
    Location:
    YO11 2BD
    Ratings:
    +28,944
    Poor quality (price means nothing) or too long/thin causing volt drop.
     
    • Thanks Thanks x 1
  4. magicsurfbus

    magicsurfbus

    Joined:
    Oct 11, 2010
    Messages:
    4,685
    Location:
    NW England
    Ratings:
    +14,761
    When I use my 12v Chinese knock-off Mac laptop charger it takes a lot of oomph out of the leisure battery, I think because it's stepping up the voltage. In my last MH the leisure battery voltage (normally healthy) dropped some way below 12v whenever the laptop was charging.

    If your leisure battery is already in demand from other items a laptop charger might not get enough power.

    We had a similar thing with our old F&H 12v TV - we had to plug its power pack into the 12v socket then plug it into the TV set, otherwise it wouldn't work. You couldn't just leave them connected up overnight and switch on at the set.
     
    • Informative Informative x 1
  5. Reallyretired

    Reallyretired Funster

    Joined:
    Apr 27, 2008
    Messages:
    7,113
    Location:
    Eastbourne East Sussex
    Ratings:
    +5,860
    If it works without the extension then the extension must have too high a resistance. You can get high wattage extension from ebay but they are usually long ones or make up your own.
     
  6. Figaro

    Figaro Funster

    Joined:
    Feb 22, 2011
    Messages:
    2,123
    Location:
    Newcastle under Lyme Staffordshire
    Ratings:
    +2,704
    I put the multimeter on this extension lead when I got home and the voltage shown was the same as that at the Hella socket.
    Could it be that it`s the current it won`t handle ? The cable does look a bit lightweight.
    The plug and socket on the extension lead do look like they will dismantle so I might try and wire it with different cable.
    Should I order 0.5 mm, 0.75 mm or 1.0 mm ?
     
  7. tonyidle

    tonyidle Funster

    Joined:
    Aug 6, 2013
    Messages:
    6,012
    Location:
    Kendal, Cumbria
    Ratings:
    +8,148
    2.5 sq mm
     
    • Thanks Thanks x 1
  8. Guigsy

    Guigsy Funster

    Joined:
    Sep 17, 2017
    Messages:
    269
    Location:
    Birmingham, UK
    Ratings:
    +674
    Depending on the model, the laptop is probably pulling 60w (and maybe up to 90w, check the PSU) as you power it up. That's 5A on 12v before considering losses in the transformer... Quite a lot of current to be pulling.
     
    • Thanks Thanks x 1
  9. jockaneezer

    jockaneezer Funster

    Joined:
    Dec 12, 2010
    Messages:
    2,573
    Location:
    Cumbria
    Ratings:
    +8,694
    I've just bought a 12 volt step up to 24 volt 12 amp adaptor to power a small 24 volt external fuel transfer pump rated at 7 amps. Under no load the adaptor outputs 24 volts on my multi meter, connect it to the pump and it drops back to 12 volt. Out of curiosity, I connected a 12 volt 21 watt bulb to it and the voltage dropped to 14 volts. Requested some action from the seller on ebay before I post feedback. There are lots of identical units listed, mostly coming from China, but I bought from a UK based seller for a few quid extra for piece of mind. :rolleyes:
     

Share This Page

  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.
    Dismiss Notice