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Thread: Stable 240V output from inverter for Satellite box

  1. #1

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    Stable 240V output from inverter for Satellite box



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    We have a satellite dish and 12V satellite receiver which work well.
    However, when we want to watch encrypted programmes, we need to use our ĎSky plus HDí box, which requires a 240V input.
    Our old Sky box worked well powered by one of two inverters. One is high power (300W), the other small (50W). However, the new box seems to be more sensitive to the input voltage (I assume) as it works erratically, and when I checked with a DVM both of the inverters had an output voltage (little or no current flowing) well over 240V - over 300V!!! I guess it is tripping out when the voltage gets too high. The work-round has been to use a generator which provides the required 240V +/- much less than the inverters. But this is far from ideal. Don't like disturbing the countryside when we have found a good 'wild' place!

    I have seen various voltage protective devices but the problem can be that they cut the connection if the voltage exceeds a certain value. What I require is a device that will limit the voltage, constraining the output rather than disconnecting. If it cuts, the box goes off and takes time to reboot. As I see it, it needs a well-regulated power supply, like the ones used by laptop computers that provide a stable output regardless of input voltage from 100-250V. Would a surge/spike protector sold by computer shops do the job?

    Or can I break into the Sky+HD box, by-pass the power supply board and connect 12V directly to the main electronics?
    Keep them wheels turning,

    Henry
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    Quote Originally Posted by Henrym View Post
    We have a satellite dish and 12V satellite receiver which work well.
    However, when we want to watch encrypted programmes, we need to use our ĎSky plus HDí box, which requires a 240V input.
    Our old Sky box worked well powered by one of two inverters. One is high power (300W), the other small (50W). However, the new box seems to be more sensitive to the input voltage (I assume) as it works erratically, and when I checked with a DVM both of the inverters had an output voltage (little or no current flowing) well over 240V - over 300V!!! I guess it is tripping out when the voltage gets too high. The work-round has been to use a generator which provides the required 240V +/- much less than the inverters. But this is far from ideal. Don't like disturbing the countryside when we have found a good 'wild' place!

    I have seen various voltage protective devices but the problem can be that they cut the connection if the voltage exceeds a certain value. What I require is a device that will limit the voltage, constraining the output rather than disconnecting. If it cuts, the box goes off and takes time to reboot. As I see it, it needs a well-regulated power supply, like the ones used by laptop computers that provide a stable output regardless of input voltage from 100-250V. Would a surge/spike protector sold by computer shops do the job?

    Or can I break into the Sky+HD box, by-pass the power supply board and connect 12V directly to the main electronics?
    I would be surprised if both inverters were outputing such a high value. a genuine 300+ V would probably damage devices plugged into them. I would be suspicous of the DVM.
    Are the Inverters Pure Sine Wave or Modified Sine Wave? Also try the DVM on a home socket in the house and see what that reads as a control.
    This is very unlikely to be over 250V. Nominally UK mains is 230V +/- 10%
    I've checked the outout on the Inverters I have and they are all within an acceptable range
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    Cannot help you regarding inverter output voltage, complete numpty with most things electrical. Iím just curious as to why you use a sky plus hd box in your motorhome.
    Unless you are wanting the record and pause / rewind facilities just use a sky multi room box, thatís what I am using at present.
    It is physically smaller and uses under 1/2 the amps the sky plus box uses, in the depths of winter when wilding that can make your batteries last longer. I had a spare multi room box but they can be found on fleabay for next to nought.
    The most important thing is to enjoy your life - to be happy - its all that matters.

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    Buy a pure sinewave inverter.

    Some meters measure the peak value of the waveform and multiply it by a factor to give an RMS value. Works perfectly well for a pure sine wave because that ratio is fixed.
    However for a modified square wave inverter the waveform has a much higher peak voltage to RMS ratio so simple meters will/may read high.
    A good meter will actually calculate the correct value over the whole cycle.

    Even then, many electronic devices just won't work well unless they are being supplied by true sinewave supply
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    Yes have to agree with the last comments!
    To run sensitive electrical equipment like your Sky box or laptops, you most definitely require a pure sine wave inverter. If not, in time you will damage the components and in the short term will cause interference with the device e.g. humming with audio equipment.

    Gregor.
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    Like the others I think you need to check your DVM in a household socket to start with, make sure that is reading correctly. Once you have done that I would check the voltages from both invertors and your generator, is your generator a 240v inverter type?


    I have 2 inverters one is modified sine wave and the other is pure sine wave. I have tested them with a Lidl / Aldi DVM and a I have a Digital Storage Oscilloscope MT8206 Intelligent Multimeter Diode Tester. The modified sine wave inverter read 180v, (from memory), on both meters and is square wave. The pure sine wave inverter reads 220/230v and show as multi stepped sine wave, it almost as good as from the mains but not quite the same. You would need a better scope to get a clearer picture.


    Also try you system on mains, if it's all right there, and I suspect it will be as it works on your generator it may be that your inverters a square wave, there is about 4 or 5 different types of wave forms put out by different inverters, not all electrical items will work on them as they require a pure sine wave or as near to it as you can get. Of course the manufacturers tell you its pure sine wave, or modified sine wave and it just basic square wave.

    Your old sky box might have been ok and you new one isn't.
    Last edited by chas142; 06-02-2019 at 22:07.
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    Surely wild camping is not about fretting whether satellite tv is available or not, it's more about enjoying where you are . We had a system that we got when we were tuggers, so much of a faff, so we didn't use it, when we joined this group I offered it but no responce so it got chucked, which led me to believe that wild campers, like us, are content to maybe watch telly if it's available, otherwise just enjoy each others company and do stuff like we used to do before technology kicked in.
    When life gives you lemons, add them to your gin & tonic
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    Quote Originally Posted by oppy View Post
    Surely wild camping is not about fretting whether satellite tv is available or not, it's more about enjoying where you are . We had a system that we got when we were tuggers, so much of a faff, so we didn't use it, when we joined this group I offered it but no responce so it got chucked, which led me to believe that wild campers, like us, are content to maybe watch telly if it's available, otherwise just enjoy each others company and do stuff like we used to do before technology kicked in.
    I am only trying to answer the technical side, I have a tv and a satellite dish but never fitted it / used it in 15 years.

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    Quote Originally Posted by wildebus View Post
    I would be surprised if both inverters were outputing such a high value. a genuine 300+ V would probably damage devices plugged into them. I would be suspicous of the DVM.
    Are the Inverters Pure Sine Wave or Modified Sine Wave? Also try the DVM on a home socket in the house and see what that reads as a control.
    This is very unlikely to be over 250V. Nominally UK mains is 230V +/- 10%
    I've checked the outout on the Inverters I have and they are all within an acceptable range
    The big one is a solidly built older model, the smaller one Ring brand, so probably neither Pure Sine Wave. The DVM shows a fluctuating 240-250V. A bit high, but acceptable for guidance. What well-behaved inverters do you have? Presumably pure sine wave; do they have over/under voltage protection? I guess I need a quality inverter with these features, but an output power of 50-100W so that the no-load current is small - not 3000W (for example).
    Keep them wheels turning,

    Henry

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    Quote Originally Posted by Obanboy666 View Post
    Cannot help you regarding inverter output voltage, complete numpty with most things electrical. Iím just curious as to why you use a sky plus hd box in your motorhome.
    Unless you are wanting the record and pause / rewind facilities just use a sky multi room box, thatís what I am using at present.
    It is physically smaller and uses under 1/2 the amps the sky plus box uses, in the depths of winter when wilding that can make your batteries last longer. I had a spare multi room box but they can be found on fleabay for next to nought.
    In the past, I had various items that required the inverter; not now, even the computer has its solid state 19V output device that plugs into the 12V supply. Now it's just the Sky+HD box, when my wife wants to watch football when we are on the road (I have to keep her happy when I drag her out). For other programmes, the 12V Icecrypt receiver (supplied and set up by Robert Jackson) draws minimal current, and gives us the option of getting certain programmes from Hispersat. Good if there is a hill to the SE, and it also covers most of Western Europe. But, the Sky card will only unlock sports programmes (for example) when it is in the Sky+HD box - it does not work in the Icecrypt and not now (after reassignment) in the old Sky box. The evil empire is afraid of n're-do-wells infringing their monopoly! We were forced to upgrade because one footy channel went from SD/HD to HD only!
    Keep them wheels turning,

    Henry

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