inverter question

Discussion in 'Tech/Mech General' started by Mags52, Jul 18, 2012.

  1. Mags52

    Mags52 Funster

    Joined:
    Jun 2, 2010
    Messages:
    1,059
    Likes Received:
    1,106
    Location:
    Bathgate West Lothian
    We have a 12v 150w inverter. Twice I have tried to plug in my macbook and each time it has fused the 12v socket. This is a major pain as I have to go into all kinds of contortions to change the fuse (kneel on step, bum out the door, twist arm where it shouldn't go, can't see through varifocals, swear ...).
    I thought that 150w would be ample for a wee laptop.
    I'm wondering whether to go for a 200w inverter but I can't see anything on the macbook to tell me the watts required.
    Also, we want to be able to charge our cordless drill driver when away. How do I work out the watts required for that?
    As you can tell I know nothing about these things so any advice would be really helpful.
    Thanks
    Mags
     
  2. scotjimland

    scotjimland Funster Life Member

    Joined:
    Jul 25, 2007
    Messages:
    28,934
    Likes Received:
    25,574
    Location:
    .
    The 150watt inverter should be more than adequate for the mac.. On full load the inverter will pull 12.5 amps

    what size fuse is blowing ?
     
  3. Mags52

    Mags52 Funster

    Joined:
    Jun 2, 2010
    Messages:
    1,059
    Likes Received:
    1,106
    Location:
    Bathgate West Lothian
    I think its 10a (it's on the TV fuse)
    I was wondering whether I could put a bigger fuse in the TV slot?
     
  4. scotjimland

    scotjimland Funster Life Member

    Joined:
    Jul 25, 2007
    Messages:
    28,934
    Likes Received:
    25,574
    Location:
    .
    Generally speaking it's not advisable to increase a fuse size, it is sized to suite the cable, increasing may overload it and cause a fire..

    Try a lower power accessory first.. , a camera or phone charger, if that's ok then It's probably the initial surge when you plug in that mac that blows the 10A fuse.. try a 15A fuse.. but no bigger.. if the 15A blows then it may well be a faulty inverter , so proceed with caution!

    Edit

    I meant to say, check the mac power consumption.. it should be on the back, on the battery and also marked on the power adaptor.
     
    Last edited: Jul 18, 2012
  5. cbrookson

    cbrookson Funster

    Joined:
    May 5, 2011
    Messages:
    243
    Likes Received:
    120
    Location:
    Suffolk
    You may be better off getting a 12V supply for your MAC and leaving out the inverter. Amazon has a selection - for example: [ame]http://www.amazon.co.uk/12V-Car-Charger-Apple-Macbook/dp/B006CF8BAI/ref=pd_sim_sbs_computers_1[/ame]


    This will take much less of a load than an inverter off your battery .... or should do!

    Cheers
     
    • Like Like x 1
  6. Mags52

    Mags52 Funster

    Joined:
    Jun 2, 2010
    Messages:
    1,059
    Likes Received:
    1,106
    Location:
    Bathgate West Lothian
    The charger is 60w but I was using the mac and charging it at the same time. I don't know if that makes a difference.
    I suspect it is a faulty inverter but will follow your advice to test it.
    Thanks for your help Jim.
    Mags
     
  7. JeanLuc

    JeanLuc Funster

    Joined:
    Nov 17, 2008
    Messages:
    2,782
    Likes Received:
    1,859
    Location:
    Warwickshire
    A 150W inverter should be ample for a MacBook. I charge mine from a 150W model with no problem - the MacBook Pro's charging unit is rated at 85W and most good quality inverters can handle more than their rated output anyway for short bursts. I suspect your problem is caused by voltage drop resulting in the inverter drawing a higher current than the circuit can stand. Despite yours being a small inverter, voltage drop can still be a major problem and a good reason to connect it directly to the batteries.
    Read my article describing how I carried out the installation to overcome the problem.
    http://www.motorhomefun.co.uk/downloads/miscellaneous/13/instal-small-inverter-pdf-102/

    p.s. using the Mac whilst charging increases the demand, but that still should not be a problem for a good 150W inverter - I do it all the time with a bigger Mac power pack.
     
    Last edited: Jul 18, 2012
  8. motorhomer

    motorhomer Read Only Funster

    Joined:
    May 17, 2008
    Messages:
    578
    Likes Received:
    317
    Location:
    South Shropshire
    As someone else said, get a 12v power supply for the computer.

    An inverter is an extremely inefficient way of powering computers. It converts 12v dc to 230v ac and then the computer power supply converts it back to dc, probably 19v. Far better (and kinder on the battery) to get a power supply that just adjusts the voltage. Another possible supplier of one of these is Maplin.

    I have a 300watt inverter, which at first I tried to use from a 12v socket to power my laptop. Basically it didn't work because the cable in the van is rated at about 90 watt which proved to be not enough through the inverter. But a 12v to 19v converter works fine.

    Some TV's (eg my Avtex) are also 12 volt dc so powering them through an inverter and then the mains TV power supply is also not efficient. If the TV is 12 v far better to power it directly from a 12v socket and bypass the mains connection (but make sure first!)
     
  9. JeanLuc

    JeanLuc Funster

    Joined:
    Nov 17, 2008
    Messages:
    2,782
    Likes Received:
    1,859
    Location:
    Warwickshire
    This may not be an easy option as Macs have a proprietary magnetic connecter between the power supply and the laptop, not a simple push-in plug.
     
  10. motorhomer

    motorhomer Read Only Funster

    Joined:
    May 17, 2008
    Messages:
    578
    Likes Received:
    317
    Location:
    South Shropshire
    OK I'm not too familiar with the mac. Personally I stear clear of Apple products because there is a lot that is proprietary about them, but thats me.

    What I said otherwise holds true, an inverter is not efficient especially if the power has to be converted back to dc at a similar voltage from where it started. sorry if I misled you because of the proprietary socket.

    From a brief scan on the internet I think it could possibly still be done (I think the mac is 19v) but someone would need to make up the cable to connect the mac to the power supply, unless one has been made for this purpose. But this is getting harder and possibly not worth the trouble.
     
    • Like Like x 1
  11. JeanLuc

    JeanLuc Funster

    Joined:
    Nov 17, 2008
    Messages:
    2,782
    Likes Received:
    1,859
    Location:
    Warwickshire
    The standard 60W 13" MacBook charger outputs 16.5V. The 85W MacBookPro charger outputs between 16.5V and 18.5V depending on the application. So in my view, it's easier to use a small inverter.
     
  12. hilldweller

    hilldweller Funster Life Member

    Joined:
    Dec 5, 2008
    Messages:
    26,447
    Likes Received:
    25,125
    Location:
    Macclesfield
    Ridiculous, like phones were. At least the micro USB is becoming a default charger for small gadgets.

    Is it too much to standardise on one for bigger gadgets ?

    Just imagine a house where the kettle was 110V with round pin plug, the toaster 240V with square pins, the fridge 90V with triangular pins.

    Says a man with a supermarket bag full of differing wall warts.
     
  13. JeanLuc

    JeanLuc Funster

    Joined:
    Nov 17, 2008
    Messages:
    2,782
    Likes Received:
    1,859
    Location:
    Warwickshire
    Not ridiculous at all. The Mac charger connection fits any recent MacBook and the other end has this odd 3-pin plug that seems to fit any 230V socket in the UK - that seems to be standardised from my point of view.
    As for the actual voltage delivered, like pretty much anything to do with a Mac, the user doesn't have to bother about it - it just works - it's a Mac-thing. (Unless you want to try and beat the system by using a non-standard charging converter instead of a simple small inverter that provides the 230V AC the Mac charger is expecting).
    :thumb::thumb::thumb:
     
  14. Mags52

    Mags52 Funster

    Joined:
    Jun 2, 2010
    Messages:
    1,059
    Likes Received:
    1,106
    Location:
    Bathgate West Lothian
    Hi Guys, You can get a cigarette plug type charger for the mac but I want the power socket for a rechargeable drill driver as well (screw in pegs for utility tent). It's therefore simpler to go for one bit of kit that does both jobs.
    I took the inverter to Maplin today and asked them if they could tell me whether it was faulty. Very cheeky as I didn't buy it from them. The guy plugged it in and told me it was completely dead (which was a bit embarrassing as I hadn't checked before I left). :Blush:
    So my guess is that I had a faulty inverter all along. Had it two years now so no point trying to complain.
    He advised me to check the wattage on the drill driver charger before I bought another so I'll do that and probably buy one from maplin. Impressed with their customer service after today.
    Thanks all.
    Didn't mean to start a for and against Apple discussion :Wink:
    Mags
     
  15. motorhomer

    motorhomer Read Only Funster

    Joined:
    May 17, 2008
    Messages:
    578
    Likes Received:
    317
    Location:
    South Shropshire
    I agree with Hilldweller, it is ridiculous. There may be a degree of standardisation across some mac products, but there is none between apple products and anyone else's. I am not saying apple products are not good, they are. But , for example, try to use windows explorer to look at the contents of ipod, (ie without apple's itunes) and then try with sony walkman and you will see the difference. I think its predictable that Apple would use a wholly non standard connection for the mac. Its possibly one of many bees I have in my bonnet (!) but this alone would stop me buying their products as it makes you buy apple accessories such as power supplies.
    And "a non standard charging converter" is not non standard at all, it works with pretty much any make of PC and is far better than an inverter that converts from 12v dc to 230v ac so that the mac can convert it back again. its the mac thats non standard, however good it is otherwise.

    Jeff O
     
  16. Gromett

    Gromett Funster

    Joined:
    Feb 27, 2011
    Messages:
    7,941
    Likes Received:
    14,007
    Location:
    UK
    I do think the idea of the magnetic connectors is a good one for high value devices that are portable. The fact that I trip over my laptop cable and come close to dragging it to the floor once a year makes me appreciate that the mag lock idea is excellent. It hold the connector firmly in place but will disconnect if the cable is tripped over.

    The downside is Apple will have patented the connection and won't allow third party manufacturers a license to use them....

    I think possibly the only way round this would be to be a DC/DC converter of the correct voltage and plunder the connector off an official apple power pack.

    There are a couple of macbook air car chargers on ebay. But I don't know which macbook you have or which model....
     
Loading...

Share This Page