Regulated power supply for 12V TV

Discussion in 'TV & Satellite' started by Kitbag, Apr 16, 2010.

  1. Kitbag

    Kitbag Read Only Funster

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    Would this item work as a regulated power supply for a 12V TV? The regulated power supplies that I have seen to date have been in the region on £40 to £50. Also, what are the general views on whether a regulated supply is required? Are there measures you can take to protect the TV if you don't have a regulated power supply?

    http://cgi.ebay.co.uk/12v-Regulated...arts_Vehicles_CarParts_SM?hash=item2a0151d163

    Cheers
     
  2. scotjimland

    scotjimland Funster Life Member

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    I've never used a regulated supply for a 12v TV and never had any problems..

    What wattage is your TV ?

    This particular unit is only rated at 2 amp / 24watt ..
     
  3. gazz

    gazz Formerly "gazznhelz"

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    Those things usually only regulate the voltages below 12 volts, i.e. the 9, 6, 4.5 etc, the 12 volts seting pases straiht through, so is unregulated,

    some tv's can run without a regulator, some cant, basicaly they are made to run on the supplied mains psu only, which usually has an output of 12.3 volts, hence inside the tv they e components spec'd for that voltage to save money, no point fitting more expensive components with higher tollerances when the tv ws designed to be used with the supplied psu.

    when you connect to the motorhomes 12 volt system, you dont get '12' volts, you get anything from 10.8 upto 16 volts, and a lot of spikes, ripple, transients and so on,
    the voltage will depend on wether the batteries are flat (10.8 volts is not a good voltage to go down to, but that's what most inverters cut out at), or you are on shore powe and hence the battry harger is on line, (13.6 volts on float, 14.8 volts on boost and absorbtion stages of the charge)
    or you have solar panels, depending on the regulator used you'll vary from 13.6 volts when charged fully, 14.8 when charging, and 15.8 volts when doing an equlization charge (mine does this once a month, it's to balance the cels in the battery bank)

    the tv i have in my van is one of them that blows the backlight inverter if fed with more than 12.7 volts, so i use a regulator, 40 quid was cheaper than a new tv (which was over 300 quid when i bough it 8 years ago, and it's only a 15 incher, but that was bg back then)

    i also run the dvd player and the sky box off the regulator, so i know they are protected as well.
     
  4. Kitbag

    Kitbag Read Only Funster

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    Cheers guys for both responses. Jim, your observation on the rating was spot on. My TV is 36W so that item wont work.

    My thoughts on the voltage regulators were that if I wasn't charginging the battery then I wouldn't require one. Now I'm not so sure what the right answer is.

    It would be interesting to hear more views.
     
  5. scotjimland

    scotjimland Funster Life Member

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    Hi

    Does your TV have a 230v / 12v power supply unit or is it only 12v DC ?
    If it has a power supply unit, use it when on EHU .. problem solved.

    If only 12v , do the specs, give a working range .. ?
    You could also test your 12v supply with a digital multimeter meter (DMM) under different charge stages to establish whether there is any likelihood of damaging the TV.

    The battery bank acts a voltage stabiliser, any transients or spikes from a charger are effectively smoothed and don't affect 12v equipment.. also, depending on cable size and distance from the battery there is a small volt drop, you can test this with a DMM by measuring the voltage at the battery terminals then at the socket ..

    Another point, many vans don't have all singing all dancing multistage chargers, but quite basic power supply units that never put out more than 13.8v .. check yours and do some testing before deciding.
     
  6. Terry

    Terry Funster

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    Hi we have been running various tv's / dvd and on digi freeview boxes for the last 9 years wired straight to the Ariel plug which in turn is wired direct to the l/battery without any problems at all.It is used while connected up to the EHU so is charging all the time,again no problem :thumb: My mate who mends tvs etc, says the battery works as a pretty good regulator ironing out spikes to keep a constant supply
    terry
     
  7. gazz

    gazz Formerly "gazznhelz"

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    Meh, each to their own,

    i've seen a few lcd tv's with blown backlight psu's, they were used in motorhomes and were fine untill the battery charger was used, 13.8 volts is still well over the spec for some lcd tv's, start the engine up and you'll get 14.8 volts and lots of spikes and hash on the power wires, as the alternator is an AC devise, using a rectifier to chop the 3 phases into DC, fine for charging the battery and running bulbs, but owt computer related in a vehicle has it's own built in regulators,

    tv's made for home use supplied with a mains psu dont, the regulating is done in the psu, that's why the manual will say no warrenty if used with anything other than the supplied psu.

    the battery can smooth a supply out, but it does not keep all the bad stuff away from electronics, ask anyone who's used a radio transmitter off a battery whilst on charge,
     
  8. andyman

    andyman Read Only Funster

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