Inverter

Discussion in 'The Beginner' started by RS SPIKE, Jun 9, 2016.

  1. RS SPIKE

    RS SPIKE Funster

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    Can anyone advise me on what size inverter i require to power a sky box please :)
     
  2. funflair

    funflair Funster Life Member

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    What watts does it say on the back of the Sky box? Then I would say twice that for the inverter.

    Martin
     
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  3. Don Quixote

    Don Quixote Funster

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    A 300 watt will do the job.
     
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  4. autorouter

    autorouter Funster

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    Note carefully that there are two types of inverter.

    An inverter changes 12V DC into 240 volts AC, but changing the voltage level is not the whole story. AC means the voltage changes from positive to negative and back, 50 times per second. The designer chooses whether to just switch it crudely or to make it nicely increase and decrease like a smooth water wave. The smooth wave type is called 'Pure Sine Wave' (PSW), the other type is called Modified Sine Wave (MSW) or Quasi Sine Wave. The domestic mains electric supply is always Pure Sine Wave.

    Some things like lights, heaters, drills etc can use MSW with no problem. Other things, typically those with electronics and digital controls, can have problems. I have a Nespresso automatic coffee machine (1250 watts) that just won't work on a 2000W MSW inverter.

    Unfortunately your Sky box sounds like exactly the kind of thing that will have problems with an MSW inverter. If you can try before you buy, then by all means give an MSW inverter a go. But I'd bet that you need a PSW inverter for this. It's more expensive, but for small wattages not massively so.

    Pure Sine Wave inverters are usually clearly labelled on the box/web site. MSW inverters often have this property missing or hidden down in the small print of the specification. Usually if you have to ask, it's not PSW.
     
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  5. scotjimland

    scotjimland Funster Life Member

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    Last edited: Jun 10, 2016
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  6. DavidG58

    DavidG58 Funster

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    @scotjimland

    Morning Jim, thanks for the link, I have been planning to upgrade mine, the answer may simply be the larger unit was not available when you bought yours, but from my quick scan of the spec the 800W for £7 more looks a much better option

    Will it simply take more out of the battery?

    http://www.sp-shop.co.uk/Power-Inverters/


    EDIT ignore me, didn't read properly, the 800W is the Q (quasi not sine) o_O
     
  7. scotjimland

    scotjimland Funster Life Member

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    Hi David..

    No inverter is 100% efficient.. there are losses in converting 12vdc to 240vac .. so there is a very small power loss with all inverters.. and the bigger they are the more power lost.. but in relative terms it is quite small .. a few percent of the full load.

    The power used from the battery depends on the connected load.. not the inverter rating..

    as a general rule of thumb.. buy an inverter that is about 25% bigger than you need.. the reason being, inverters are at their most efficient when used at or near full load.. a big inverter only being used at 10% of it's max load is inefficient .. it's wasting energy...

    for example.. you have a 500watt max load .. then buy a 750watt inverter.. this leaves spare power for start up loads which can be 3 or 4 times the continuous load.. but inverters can generally cope with this.. usually stated as 'continuous power' and 'peak power.'

    Quality PSW inverters deal with this by having a 40%-100% surge capacity.


    hope that helps and doesn't confuse...
     
    Last edited: Jun 10, 2016
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  8. Speve

    Speve Funster

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    I have a Maplins 300w modified sine wave inverter that runs the Sky box without any trouble the box is 45w as I recall
     
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  9. ****

    **** Read Only Funster

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  10. OwnedbyCollies

    OwnedbyCollies Funster

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    I run my Sky box with a 150w modified wave inverter - it was a very cheap one from Aldi / Lidl.

    Unfortunately my Macbook pro doesn't like the modified supply so I have just ordered a 150 pure sine wave. I will leave the Sky box on the 'cheapo' unit and use the 'good' one for charging laptop, iPads etc.
     
  11. ****

    **** Read Only Funster

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    Why not just charge from USB in the van power sockets while on the go?
     
  12. scotjimland

    scotjimland Funster Life Member

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    how do you charge a MacBook Pro from a usb ?
     
  13. ****

    **** Read Only Funster

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    I dont know. I was presuming the ipads and etc would be mobile phones.
     
  14. scotjimland

    scotjimland Funster Life Member

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    yes.. you can charge an iPad and mobile phone from a USB .. but not a laptop..

    however.. you can charge most laptops from a 12v adapter.. but there isn't an Apple approved one to charge a MacBook Pro .. I believe there are third party adapters.. but I won't risk damaging an expensive laptop .. hence buying the PSW Sterling Inverter
     
  15. Rob Turner

    Rob Turner Funster

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    You could buy a 12v sky box
     
  16. RS SPIKE

    RS SPIKE Funster

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    Yes then I need another sky card and can't view programs from the planner
     
  17. Rob Turner

    Rob Turner Funster

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    Sorry, didn't realise you were taking the one out of the house.
    My 12v sky box is set up as multi room and get everything including the planner just as if I were at home.
     
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  18. Lot lover

    Lot lover Funster

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    Am I correct in suspecting that somewhere on my little black box will be a label telling make, model no, output and all sorts of other things that I will not understand?

    And am I correct in guessing that it will be behind or underneath something seemingly welded in place?

    And other than the label they all look the same?
     
  19. Speve

    Speve Funster

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    You can get a sky pace box which are no longer made but they are not HD and hard to find but you can use the card out of your home Sky box in it.
    Just search pace javelin on eBay
     
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  20. Squeezy

    Squeezy Funster

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    Would this charge an electric bike battery, @scotjimland?
     

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