LCD TV on 12volts
- Thread starter alan_5039787
- Start date
hi, its just the same as 240,never had any problems we always use 12v even when on electric hookup.
Hi Alan - I think you've got to be careful here.I run a LCD off 12V using a "transformer"(???) from the mains, 240V,but apparently I cannot use it off 12V.dc (the battery).Find it very confusing, but I've been told it's a no no.
We have used the Manhattan 15in LCD TV on 12V almost exclusively for 3years with no problem once the 12V supply cable had been uprated and shortened.
www.Leisurepower.co.uk and others do a voltage stabiliser for use with 12V TV's
www.Leisurepower.co.uk and others do a voltage stabiliser for use with 12V TV's
You need a convertor from 12 volt to 240 volts. Eventhough the TV may be 12 volts we were told that it was the ampage that was the problem. Unless your TV has a 12 volt socket don't do it.
Surely the socket on the Tv is 12V if its being fed by a 12V transformer.
You only have to read the rating plate on the transformer/power pack to see what the spec is
You only have to read the rating plate on the transformer/power pack to see what the spec is
Hello Alan, and others
You have some answers above, that seem to contradict each other, and there are elements of truth in all, so I think you may need a bit more explanation. I hope this does not confuse you further.
As you mention 12V power lets consider that first. The "12V" system in a caravan is usually anything but 12V.. when the charger is on the voltage can rise to 13.8V, and when the battery is running down the voltage will fall ultimately to 0V, but in practice a minimum of 10V to 10.5V would be considered a flat battery.
Another factor that also affects the voltage available to the TV, is the total Amps being used by all the appliances which will cause a 'Voltage drop' along the wiring between the battery ad the TV. The more Amps used the greater the voltage drops.
This wide range of voltage can be a problem to some makes of LCD television. Some sets require 12V exactly; others can tolerate a wider range of input voltage. Most sets have a power pack, which you use at home that converts 230V ac to the accurate 12Vdc the set needs.
There is another way that you might resolve this issue, and "John" has alluded to it. There is a device called an 'Inverter' which connects to a 12V dc supply and produces 230V ac (like mains supply). It is the converse of a 12V power supply.
Whilst it is not entirely accurate because of inefficiencies we can for the purposes of this discussion assume that both power supplies and inverters are 100% efficient. This means that Power In (Watts) =Power Out (Watts). In electrical terms power (Watts) can be calculated from Volts and current (Amps):-
Volts X Amps = Watts
If your LCD is rated at 12V at 5A then using the above formula we can see the power rating is 12V x 5A = 60W. At 5A current, a significant voltage drop may be caused in the wiring. Because Power (Watts) is conserved through the power supply then if the input voltage is now 230V then current is given by translating the formula so that Volts DIVIDED by Watts = Current : 230/60= 0.25A (Approx)
This much-reduced current will produce a much smaller voltage drop in the cable,
Incidentally this is why the generating companies distribute power along our pylons at 11,000V or even 230,000V to reduce transmission losses due to cable resistance.
Inverters have limited power capacity (Watts). These will be fine for the TV, but don't expect to run high-powered equipment such as a hair dryer or microwave from them. The sets own power supply can be plugged into the inverter. It does mean you can use some other low powered equipment as well such as a DVD player or a laptop computer. But be warned that they will use up battery power quite quickly at. There are power losses due to inefficiencies these will be about 10% and are usually lost as heat.
Sadly I cannot offer any guidance on the suitability of different models, so it is important to tell you TV supplier of your intended usage, and to ask for a written guarantee that the product will work under such wide operational conditions: then if it does not, the retailer has failed to supply goods fit for purpose, and you would be entitled to your money back.
You have some answers above, that seem to contradict each other, and there are elements of truth in all, so I think you may need a bit more explanation. I hope this does not confuse you further.
As you mention 12V power lets consider that first. The "12V" system in a caravan is usually anything but 12V.. when the charger is on the voltage can rise to 13.8V, and when the battery is running down the voltage will fall ultimately to 0V, but in practice a minimum of 10V to 10.5V would be considered a flat battery.
Another factor that also affects the voltage available to the TV, is the total Amps being used by all the appliances which will cause a 'Voltage drop' along the wiring between the battery ad the TV. The more Amps used the greater the voltage drops.
This wide range of voltage can be a problem to some makes of LCD television. Some sets require 12V exactly; others can tolerate a wider range of input voltage. Most sets have a power pack, which you use at home that converts 230V ac to the accurate 12Vdc the set needs.
There is another way that you might resolve this issue, and "John" has alluded to it. There is a device called an 'Inverter' which connects to a 12V dc supply and produces 230V ac (like mains supply). It is the converse of a 12V power supply.
Whilst it is not entirely accurate because of inefficiencies we can for the purposes of this discussion assume that both power supplies and inverters are 100% efficient. This means that Power In (Watts) =Power Out (Watts). In electrical terms power (Watts) can be calculated from Volts and current (Amps):-
Volts X Amps = Watts
If your LCD is rated at 12V at 5A then using the above formula we can see the power rating is 12V x 5A = 60W. At 5A current, a significant voltage drop may be caused in the wiring. Because Power (Watts) is conserved through the power supply then if the input voltage is now 230V then current is given by translating the formula so that Volts DIVIDED by Watts = Current : 230/60= 0.25A (Approx)
This much-reduced current will produce a much smaller voltage drop in the cable,
Incidentally this is why the generating companies distribute power along our pylons at 11,000V or even 230,000V to reduce transmission losses due to cable resistance.
Inverters have limited power capacity (Watts). These will be fine for the TV, but don't expect to run high-powered equipment such as a hair dryer or microwave from them. The sets own power supply can be plugged into the inverter. It does mean you can use some other low powered equipment as well such as a DVD player or a laptop computer. But be warned that they will use up battery power quite quickly at. There are power losses due to inefficiencies these will be about 10% and are usually lost as heat.
Sadly I cannot offer any guidance on the suitability of different models, so it is important to tell you TV supplier of your intended usage, and to ask for a written guarantee that the product will work under such wide operational conditions: then if it does not, the retailer has failed to supply goods fit for purpose, and you would be entitled to your money back.
John I am confused over your answer how does using a invertor reduce the current taken from the 12volt socket it will increase the current taken from the 12 volt socket due to the losses you mentioned, yes it will reduce the curent along the cable from the invertor to the TV but the curent on the 12 volt side of the invertor will be increased due to said losses.
Or are you advising putting the invertor next to the battery and running the cable to a 230 volt socket, which would be the way to reduce voltage drop.
The wiring in modern caravans defies all understanding at times.
in our 2003 Ace Jubilee Statesman the battery all 4st 3lb of it was placed at the rear offside of the caravan with the TV almost directly above it but 5ft towards the front of the van.
The cable to the TV point then went along the floor and did almost a full lap before arriving at the control panel in the wardrobe from where it went back to the TV completing a full lap and losing some energy through voltage drop on the way.
I shortened the cable by going directly from the battery(via a fuse) with thicker cable and used the original feed to trigger a relay so that the habitation relay still switched off the Tv point when towing.
In our present Bailey the TV aerial is about 3 metres from the TV but the aerial lead goes away from the Tv to the front of the van,drops to the floor .comes back to below the TV and then rises the height of the van before reaching the TV
In these days of computer aided design one can only be amazed !!!
Incidently in later Ace/Swift caravans the brochure proudly proclaimed "uprated TV point"
Perhaps we can look forward to "uprated Tv aerial point" in new Baileys in the future.
You have to smile !!
in our 2003 Ace Jubilee Statesman the battery all 4st 3lb of it was placed at the rear offside of the caravan with the TV almost directly above it but 5ft towards the front of the van.
The cable to the TV point then went along the floor and did almost a full lap before arriving at the control panel in the wardrobe from where it went back to the TV completing a full lap and losing some energy through voltage drop on the way.
I shortened the cable by going directly from the battery(via a fuse) with thicker cable and used the original feed to trigger a relay so that the habitation relay still switched off the Tv point when towing.
In our present Bailey the TV aerial is about 3 metres from the TV but the aerial lead goes away from the Tv to the front of the van,drops to the floor .comes back to below the TV and then rises the height of the van before reaching the TV
In these days of computer aided design one can only be amazed !!!
Incidently in later Ace/Swift caravans the brochure proudly proclaimed "uprated TV point"
Perhaps we can look forward to "uprated Tv aerial point" in new Baileys in the future.
You have to smile !!
Just a point about inverters.
The instructions with mine said that the 12V lead should be as short as possible but that the 230V lead could be longer so plugging into the existing 12V TV point with factory thin cabling would seem not recommended.
I would go the way of thicker cable to the 12V point and try it .
If it is unsatisfactory then get one of the voltage regulators as sold by leisure power.
Incidently trying to get a 12V lead for an LG TV for a friend became an epic search which ended up at Leisure Power.
The LG (as has our Manhattan) works well on 12V direct from the van battery(with thicker cable) without any reguator.
The instructions with mine said that the 12V lead should be as short as possible but that the 230V lead could be longer so plugging into the existing 12V TV point with factory thin cabling would seem not recommended.
I would go the way of thicker cable to the 12V point and try it .
If it is unsatisfactory then get one of the voltage regulators as sold by leisure power.
Incidently trying to get a 12V lead for an LG TV for a friend became an epic search which ended up at Leisure Power.
The LG (as has our Manhattan) works well on 12V direct from the van battery(with thicker cable) without any reguator.
Am I correct therefore in saying that we have three options?
(1) Short/upgrade wire to the battery
(2) Use an Inverter, or
(3) Use a Voltage Regulator.
Am I also correct in saying if we use No.1 method and it isn't successful, it still wont cause any harm to the TV?
Hello PaulA,
Well spotted. I forgot to say where to place the inverter. It should of course be near the battery to minimise cable losses.
However using an inverter at the side of the TV, would also work, because the electronics in the inverter will compensate for voltage drop, and still produce a nominal 230V out put, in addition the TV's own power supply will most likely be a switch mode device which also compensates for supply line variations, so the set would work reliably under these conditions. Sadly the down side of the inverter/power supply combination is that the system draws more current to compensate for the voltage losses.
Well spotted. I forgot to say where to place the inverter. It should of course be near the battery to minimise cable losses.
However using an inverter at the side of the TV, would also work, because the electronics in the inverter will compensate for voltage drop, and still produce a nominal 230V out put, in addition the TV's own power supply will most likely be a switch mode device which also compensates for supply line variations, so the set would work reliably under these conditions. Sadly the down side of the inverter/power supply combination is that the system draws more current to compensate for the voltage losses.
Hello Watson(John G) and Eddie.
John, I follow your logic about the thicker 12V cable, and yes it may work in your case with your set, but other makes may be even less tolerant than yours.
I am not familiar with the "regulator" sold by Leisure Power, however having looked at their web site, their model DCDC-Reg 70, is actually called a stabiliser. This looks as though it uses switch mode technology to produce a stable 12V output for a wide range of input voltages.
This would be simpler to use than an inverter/power supply combination.
Eddie
Note my comment to John about model tolerance; it may work for John's combination but not all. This may invalidate the TV's guarantee.
The inverter method is almost guaranteed to work, because its using the TV's own mains power supply.
The stabiliser should work, but as Leisure Power state, they cannot guarantee correct operation, and it may invalidate the TV's own guarantee.
John, I follow your logic about the thicker 12V cable, and yes it may work in your case with your set, but other makes may be even less tolerant than yours.
I am not familiar with the "regulator" sold by Leisure Power, however having looked at their web site, their model DCDC-Reg 70, is actually called a stabiliser. This looks as though it uses switch mode technology to produce a stable 12V output for a wide range of input voltages.
This would be simpler to use than an inverter/power supply combination.
Eddie
Note my comment to John about model tolerance; it may work for John's combination but not all. This may invalidate the TV's guarantee.
The inverter method is almost guaranteed to work, because its using the TV's own mains power supply.
The stabiliser should work, but as Leisure Power state, they cannot guarantee correct operation, and it may invalidate the TV's own guarantee.
Thanks very much John L.
In Jan.2006 edition of P.C., thay did an article on Power Inverters. Can anyone remember which one they reckoned to be the best value?
In Jan.2006 edition of P.C., thay did an article on Power Inverters. Can anyone remember which one they reckoned to be the best value?
Eddie I would go for option 1 first (uprate cable) but check with dealer/manufacturer as to your TV tolerance.
When I bought the Manhattan the dealer asked how long I would like a 12V cable so he obviously knew that it was OK on 12V.
It was very expensive 3 years ago but is superb so probably worth it in the long run.
When I bought the Manhattan the dealer asked how long I would like a 12V cable so he obviously knew that it was OK on 12V.
It was very expensive 3 years ago but is superb so probably worth it in the long run.
i bought a 15 inch lcd from asda it has is own transfomer with it it was a RELISYS RLT 1520 it was about
TRENDING THREADS
-
-
-
-
-
12v supply to fridge fault after testing voltage !! Help please
- Started by Joggerdude
- Replies: 4
-
-
Facebook
Twitter