12v television

[markallday]

Hi,

I've read in many forums that buying a LCD TV that was 12v would be ok to run off the battery in my caravan with the right lead.

I bought the tv and on the adaptor it says 12v 5 amp, will a normal car lead with the same wattage work, for example, I've found one on ebay:

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=350248598803&ssPageName=ADME:X:AAQ:GB:1123

 

[TonyH1]

Hi Reecea, I don't think the item you've found on ebay is suitable. The description states it is unregulated and a direct connection from battery to appliance.

You really do need a regulated supply as the battery voltage will vary from a possible 14+ volts when on charge down to less than 11 volts if allowed to go flat.

If you take a look at http://www.maplin.co.uk/Module.aspx?ModuleNo=44736 This is more appropriate but I would check in store to be completely sure.

 

[donb]

I run my standard (

 

[AlanJ]

I run my 12v LCD tv direct from the 12v battery supply along with my 12v sky digibox without any issues at all.

Just like 240v TV supplies which can be anything from 210 - 250v then a proper 12v TV will be engineered to work on a supply between 10.5v and 14.2ish).

This topic has come up many times on various forums and there are an awful lot of people running them direct from 12v without any issues.

 

[markallday]

I've been to Maplin's and they are saying I should use an inverter is this the way to go?

It seems a bit excessive

 

[markallday]

Hi,

I think this is the route to go, but how did you get a cable to go direct from the battery and fit the tv

thanks for your help

 

[JTQ]

Maplin's advice to use an inverter converting the batteries supply to a pseudo mains voltage and using the adaptor that came with the TV is a sound way of doing it that effectively does away with the risk of damaging your TV. This has advantages in that you only need to buy a 150 Watt inverter and that is a handy bit of kit to have anyway.

However its going to drain the battery quite a bit more than if you have a lead that connected the TV to the battery. [ About 40% more I suggest as a guidance figure]

If you do the latter and connect to the battery then discipline yourself to only use that lead whilst your are off EHU an use the supplied adaptor if you are on EHU.

This way you will virtually eliminate over voltage issues. Whilst many get away without problems with a direct supply all the while, they are simply being lucky.

If you have a diy adept friend they can easily make up the required lead. If you take your TVs mains adaptor into Maplins the counter staff will find you a suitable plug like on the lead; you will also need to buy a Car 12 plug and a couple of metres of twin core 5-10 amp DC wire, all from Maplins. Then take them to that friend with a couple of cans of beer; simple?

 

[JTQ]

Maplin's advice to use an inverter converting the batteries supply to a pseudo mains voltage and using the adaptor that came with the TV is a sound way of doing it that effectively does away with the risk of damaging your TV. This has advantages in that you only need to buy a 150 Watt inverter and that is a handy bit of kit to have anyway.

However its going to drain the battery quite a bit more than if you have a lead that connected the TV to the battery. [ About 40% more I suggest as a guidance figure]

If you do the latter and connect to the battery then discipline yourself to only use that lead whilst your are off EHU an use the supplied adaptor if you are on EHU.

This way you will virtually eliminate over voltage issues. Whilst many get away without problems with a direct supply all the while, they are simply being lucky.

If you have a diy adept friend they can easily make up the required lead. If you take your TVs mains adaptor into Maplins the counter staff will find you a suitable plug like on the lead; you will also need to buy a Car 12 plug and a couple of metres of twin core 5-10 amp DC wire, all from Maplins. Then take them to that friend with a couple of cans of beer; simple?

If you go the inverter route tell the supplier what you intend doing. This is because there is a slight possibility some very cheap inverter might give you a less than perfect TV picture; if so you can return the inverter and try a different one. I have four inverters and none of mine have given such interference.

 

[xtrailman]

Reecea

You need to check the tv manuel and establish the required input range for that particular product.

My old non LCD tv could work down to 10 volts, i am not sure what the tolerance of LCD tv's are, but i would check out the tv manuel.

All i did with our old tv was replace the dc lead plug so i could fit it to the van 12v supply.

We only use EU sites,so only have a mains tv, but i carry an 150 watt inverter which is for emergency use only, having twice two years ago had a site wide power cut.

 

[Chris_374413356]

I think you will find that the TV will have a regulating voltage capability, so plus or minus 2 volts will not harm the TV.

Don't go down the inverter route, they are extremely inefficient, tend to be noisy and of course extra weight to carry and very expensive for a good one.

 

[colin-yorkshire]

Reecea

I noticed this thread this morning and was going to reply but thought better of it untill I consulted with a tv engineer friend of mine, his first question was will the tv run on 240v as well as 12v or is the unit 12v only. and which lead did it come supplied with. neither question I could answer.

but basicaly if it runs with either 240 and 12v it does not need a regulated lead. as the set will be self regulating if the tv is 12v only it depends on the type of lead supplied with it however he could not see why you would need a new lead in this case as it is only the supply end of the lead that would be different, in which case you would simply attach the appropriate plug to that end to the lead.

colin

 

[ProfJohnL]

Hi Rebecca

There is a lot of well intentioned advice in the above replies. Some of it seems to be conflicting, and yet it may all be true. The problem is it might be true for the models the correspondents have but wrong for yours, as we don't know what make of model it is.

If the set was sold as being suitable to run direct from a car or caravan battery, the designers will have made it voltage tolerant.

We do know that your set is supplied with a 12Vdc 5A power supply unit (PSU). This will be a regulated PSU and will keep its output voltage tightly controlled. It is very unlikely to alter more than +/-0.5V (11.5 to 12.5V). Some electronics are particularly sensitive to voltage which is why 'regulated' PSU's are often necessary.

The caravan '12V' supply will have enough current, but its voltage may vary between 10.5 to 13.8V. This is obviously a much wider variation.

What we don't know is how your TV will respond to the wider range of voltages. It is almost certain the set will not be damaged if the voltage falls below 11.5, but it may stop working until the voltage rises.

The problem may be if the voltage goes above 12.5V we just don't know if there are any voltage sensitive devices in your set that might be damaged by the excess voltage.

Using an inverter is certainly one way, and if that is what you decide to do I suggest you look out for one that provides a true sine wave output. Most will offer a pseudo sine wave output, and these may not work with the TV sets PSU. Any inverter should be connected as close to the battery with the shorted 12V leads as possible. It is better to use a standard 13A mains extension to get the inverters output to where you want to use it.

The alternative may be the following item form Maplin.

http://www.maplin.co.uk/Module.aspx?ModuleNo=225739#Faq
This is a laptop power supply that can set to a variety of output voltages including 12V. It has a capacity of 4.5A (which should be enough for your tv) This is a DC to DC switching regulator and should provide the necessary power and supply stability for your set.

 

[Woody3]

For the record the laptop PSU is a mains AC to multi-volt DC switched mode power supply (SMPS.)

You can get 12V-12V switching convertors for isolation purposes which will take quite a wide input voltage range and provide a regulated nominal 12V out (in practice 13.8V but there is usually an externally accessible adjustment.

Alfatronics at Thurcroft near Rotherham used to make such but I don't know as of now. Their products carry a lifetime guarantee.

 

[TonyH1]

Hi Reecea, I still stand by my advice. The product I suggested is less than

 

[ProfJohnL]

Please re-read the item specification and look at the components supplied.

It clearly states "Power your laptop from home, in the car or on a plane"

Part of the kit of bits includes the 12Vdc cigarette lighter connection.

This will do the job!