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Tv on a boat.

Discussion in 'General Electronics Discussion' started by Feeling346, Apr 10, 2016.

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  1. Feeling346

    Feeling346

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    Apr 10, 2016
    Hi all. I'm a new member and know little about electronics but need help. I have a sailing boat that has a 12volt electrical system. I wish to run a TV on it and current consumption is very important. I have a brand new Samsung LED TV that would normally run from a transformer plugged into household mains. The TV requires 14volts DC. So I bought a DC-DC boost converter plugged it into the boat electrical system and carefully adjusted the output to 14volts. It destroyed the TV instantly. I then some how came to the conclusion that it needed a regulated supply so I bought a new DC-DC converter but this one had two pots to control both the current and the voltage. I had previously measured the current draw when I plugged it into the house and it drew between 1.2 - 1.6 amps. Fortunately the retailer swapped the now dead tv for a new one and I started again. Carefully adjusted the the outputs to 1.6 amps @ 14volts and plugged in. The TV worked perfectly!. Problem solved. Switched it off and switched it on again 5 minutes later and it's dead and a nasty smell of burning from the TV. Retailer swapped TV again. This time I bought a new Dc-DC converter with a digital readout so not only could you set the parameters for the volts and amps without using a seperate meter you could see what the TV was drawing in real time. Wired it up and switched on. Perfect. Ran the TV for a couple of hours and was very happy. Switched off and went and had a coffee. Came back switched it on again and the TV died instantly accompanied by the now familiar smell of burnt electrics from the TV. Clearly I'm doing something really stupid and the first people that read this will be laughing their heads off. However, once you've stopped laughing please tell what the stupid thing that I'm doing is and maybe the solution to my very frustrating problem.
     
  2. AnalogKid

    AnalogKid

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    Jun 10, 2015
    "Switched it off..." three times. - What is "it"? Was the TV turned of with the converter still connected and powered up? If so, what was the converter output voltage with no load?

    And, do you really think anyone can help with no more tech detail than "smell of burning..."?

    Make and model number of the TV?
    Clear close up photo of the model number/power requirements label on the back of the TV AND on the mains power supply?
    Photo of the mains power supply with both connectors?

    ak
     
  3. Feeling346

    Feeling346

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    Apr 10, 2016
    Hi. My mistake for not making myself clear in the posting. "Switched it off" refers to me switching off the TV. This I did by cutting the power supply to the DC-DC converter. The converter voltage was adjusted and set without load. I have no more technical detail than a "smell of burning". The TV is a Samsung 24 inch LED model number T24E310EX. The power and load requirements on the back of the TV are 14 volts DC/ 2.5 amps. The transformer that was supplied with the TV says on the back. Input 100-240 volts AC 50/60hz 1.0Amp. Output 14volts DC 2.5Amps.
    Kind regards. Feeling346
     
  4. AnalogKid

    AnalogKid

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    Jun 10, 2015
    Why? Why not turn the TV off the normal way, by pressing the power button on the remote? This maintains a small load on your power converter at all times, and could be critical in keeping things working correctly. What is the DC/DC boost converter you are using to turn 12 V into 14 V?

    ak
     
  5. Alec_t

    Alec_t

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    Jul 7, 2015
    If you switched off the input of the converter without switching off the set itself first that might have been a problem. This is what the manual says :-
    Caution.PNG
     
  6. duke37

    duke37

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    Jan 9, 2011
    Try the TV without the convertor, it may be quite happy on 12V.
     
  7. Feeling346

    Feeling346

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    Apr 10, 2016
    I don't think that's a viable option. My very first attempt at getting this TV to work was to plug in a DC-DC converter supplying 14 volts { what the data on the set said is required} and that destroyed the TV instantly. It killed the TV before I had the chance to even turn it on.
     
  8. AnalogKid

    AnalogKid

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    Jun 10, 2015
    Polarity?
     
  9. Feeling346

    Feeling346

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    Apr 10, 2016
    It seems you are suggesting that turning off the power at source may be instrumental in destroying the the TV. I have to say I find that almost impossible to accept. I live in an area where power cuts are not infrequent and no other electrical equipment in my house appears to suffer as a result of this. As to "what is the DC-DC converter" I'm using. It's exactly as described. If supplied with 12volts DC the output can be adjusted from 12volts to about 35volts. The current can also be adjusted as required. Regards Feeling346
     
  10. Feeling346

    Feeling346

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    Apr 10, 2016
    Good question. Checked it, checked it and checked it again. Compared the polarity with the original transformer just to make sure I got it right. Please keep coming back to me. I'm convinced I'm doing something wrong Regards Feeling346
     
  11. debe

    debe

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    Oct 15, 2011
    Here in Australia lots of people who holiday in caravans use TVs like you have straight of there 12V DC battery system. They don't seem to have any problems with there voltage. It will be about 12V & then 14V when the battery is being charged. You don't need a DC-DC supply.
     
  12. AnalogKid

    AnalogKid

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    Jun 10, 2015
    The "not infrequent power cuts" are to the Samsung power supply that came with the TV, one designed to protect this TV from power dropouts. The DC/DC converter on the boat has no such pedigree. Since there are at least 5 different circuit topologies for such a converter, several of which have no short circuit protection or soft start current limiting, the description you have given so far contributes nothing to solving the problem.

    In its most basic form, a non-isolated boost converter power path is input connector > inductor > diode > output connector. There is no series pass element to ramp things up slowly, limit current, etc.

    Since the TV works fine when operating with its intended power supply and intended power source, by definition ***all*** of your problems are with the DC/DC converter. My vision is not good enough to see it from six time zones away, plus there's that whole-curvature-of-the-earth thing. No details, no answers.

    Link to seller's website where you bought it
    manufacturer
    model number
    photo

    ak
     
    davenn likes this.
  13. Feeling346

    Feeling346

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    Apr 10, 2016
    This is why I need help. As I said in my first post I know little about electronics. Both of the two converters I used in the last attempts do have current limiters and they were set to a maximum of 1.6amps. Both initially worked perfectly and the unit with the built in digital readout ran th TV for a couple of hours. It was only after I had switched the TV off and then back on again that they fried the TV. I bought these converters after seeing the reviews posted by Julien Illett and Jim Connor on Youtube. The unit with the digital readout built in came from Ellieshang on Ebay and was described as a DC-DC 400w 6-40v to 8-80v led boost converter. The other converter came from Earthshoptop also on Ebay and was described as a 10A DC-DC 600W 10-60V to12-80V Boost converter power supply ET. I found the the reviews by the 2 guys on Youtube very useful and it was those that prompted me to buy these units. Regards Feeling346
     
  14. duke37

    duke37

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    These convertors use an inductor to pass the energy to the output and are quite capable of producing a very high voltage if not smoothed properly or not loaded. You could use it to float charge a battery - set it to 13.8V - and use the battery to drive to TV. Any spikes would be greatly attenuated.

    If you insist on using the convertor without the battery, then put a powerful 14 or 15V Zener diode across the output.

    The TV is intended to run on 12V with the capability to withstand 14V which is the voltage of a 12V battery on charge.

    Where do you get a TV supplier that will replace a series of TVs that you have bust?
     
  15. Alec_t

    Alec_t

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    Jul 7, 2015
    So do I, but that's what the CAUTION in the user manual suggests (see post 5)! Converters contain a substantial inductor, so switching them off is likely to generate a voltage spike. A poorly designed converter might let this get through to the load.
     
  16. AnalogKid

    AnalogKid

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    Jun 10, 2015
    What we have here is 'failure to communicate.'
    Strother Martin to Paul Newman

    With a high-power non-isolated boost converter as the power supply for a low-power load, turning off its power source is the direct cause of all of your problems. I recommend that you accept that.

    According to Samsung's support site, the TV model number you posted is not valid.

    ak
     
    Last edited: Apr 11, 2016
  17. Feeling346

    Feeling346

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    Apr 10, 2016
    Thank you duke37. At last someone coming up with a sensible logical constructive response backed up with reasoning. You're the person I've been looking for all along. Even with my limited knowledge it makes absolute sense. I think based on what you have said I shall try connecting it straight to the 12volt battery with nothing in between. Regards Feeling346. PS Currys
     
  18. duke37

    duke37

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    Jan 9, 2011
    If you start an engine with an electric starter, then high voltage pulses can be generated. A zener voltage limiter would be good.
     
  19. Gryd3

    Gryd3

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    Jun 25, 2014
    Please note that the boost converters you have are not magic, and setting the current *and* voltage will not always produce nice results.
    When the current limit is reached, the boost converter will decrease the output voltage to compensate. This should not have been a problem in any of the situations. It does most certainly sound like the problem is caused by excessive noise and/or spikes from the DC-DC converter directly, or by how you turn-off the converter.
    Using a zener diode will help clamp the voltage as a pre-determined level and using a capacitor will help smooth out ripple and spikes. These DC-DC converters are not meant to be as accurate and smooth as the OEM AC-DC adaptor. Additional care should always be considered when wiring a 'DIY' style power supply.
    As mentioned above as well, the engine+alternator or other 12V accessories can cause the output from the boat's battery to be anywhere from 14.4V when charging to a little under 12V when the engine is off. You will also need to put up with a lot of noise generated by the alternator.
    There's been a number of suggestions on here, but nothing that anyone can say with 100% certainty due to missing details of the DC-DC converters, but the suggestions here should help you mitigate any of the problems we *think* is killing the TV.
     
    Last edited: Apr 11, 2016
    duke37 likes this.
  20. Feeling346

    Feeling346

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    Apr 10, 2016
    Thanks. I think with all these helpful suggestions I'm getting some where at last. I shall be testing the TV again on Wednesday. I'll keep you posted. Regards Feeling346
     
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