Powering our new TV

[Ange]

Was this TV sold as a 230v/12v or is it just a TV that has a psu in its supply.

 

Check that the psu output is 12v DC and not 12vAC, if its output is AC then I do not think the TV will like 12vDC

 

If the TV is not a dual voltage then the warranty will be null and void if run from the incorrect supply (how they will prove that I do not know but pre warned is pre armed.)

 

Bottle - thank you! We just spotted this post (despite the large font!), checked the TV and it's only AC!!!

 

So we need a psu that'll take 12v DC to 12v ACif such a thing is available.

 

We're buying batteries this week so hopefully will be able to run off the invertor without engine - though after deliberately buying a 12v TV it does seem a shame to use an invertor to ramp it up to 240v and then back down to 12v.

 

We're still getting our heads round this stuff, learning by our mistakes most of the time

[Keeping Up]

So we need a psu that'll take 12v DC to 12v ACif such a thing is available.

The correct technical term for that is "an inverter"

[Ange]

The correct technical term for that is "an inverter"

 

 

(/me whispers quietly - do invertors take from 12v DC to 12v AC?)

[Keeping Up]

 

(/me whispers quietly - do invertors take from 12v DC to 12v AC?)

(replies quietly) Yes, the term generally refers to devices that take a dc supply such as 12v, and convert it to an ac supply such as 12vac or 240v ac.

 

Your problem is that 12vdc-240vac inverters are very common, 12vdc-12vac inverters are much less so.

 

Both types are probably of similar efficiency, although of course if you could get a 12v one it would eliminate the inefficiency of the 240v-12v transformer (which I assume it is) that came with the TV. All the same, do not assume that your existing inverter is necessarily inefficient (unless you actually know otherwise).

[Ange]

(replies quietly) Yes, the term generally refers to devices that take a dc supply such as 12v, and convert it to an ac supply such as 12vac or 240v ac.

 

Your problem is that 12vdc-240vac inverters are very common, 12vdc-12vac inverters are much less so.

 

Both types are probably of similar efficiency, although of course if you could get a 12v one it would eliminate the inefficiency of the 240v-12v transformer (which I assume it is) that came with the TV. All the same, do not assume that your existing inverter is necessarily inefficient (unless you actually know otherwise).

 

Thanks Allan - my steep learning curve continues with more than a little help from my friends

[Nickhlx]

(replies quietly) Yes, the term generally refers to devices that take a dc supply such as 12v, and convert it to an ac supply such as 12vac or 240v ac.

 

Your problem is that 12vdc-240vac inverters are very common, 12vdc-12vac inverters are much less so.

 

Both types are probably of similar efficiency, although of course if you could get a 12v one it would eliminate the inefficiency of the 240v-12v transformer (which I assume it is) that came with the TV. All the same, do not assume that your existing inverter is necessarily inefficient (unless you actually know otherwise).

 

 

Well, at the risk of possibly placing a cat amongst the proverbial pigeons... I would dare to suggest that the device requiring a.c. may actually work fine on a diet of d.c. -- this is because the first thing that it may do with the input is pass it through a bridge rectifier and turn it into d.c. so it can work with it....

 

However, I couldn't recommend you try it without looking at the circuit diagram ( if available - unlikely - or the circuit board itself and seeing what the path is that it follows, and going through what components. One slight advantage of something saying it requires 12 volts a.c. is that it actually needs only about 9.6 volts after a bridge rectifier pack, and the polarity " doesn't matter " as the diode pack will cope with that by presenting the electronics with the correct polarity after the rectifier pack. Only a couple of days ago did I need to find another psu for a failed one powering a hub here at home, and this was just the scenario, so I gave it 7.5 volts d.c. instead of 7.5 volts a.c. and all was working a few mins later - it actually worked on 6 volts d.c after the bridge rectifier pack.

 

Nick

[Chris Pink]

Fed up after missing the end of yet another TV program because of the lappy with its TV dongle dying on us, we bought a TV yesterday. For those that don't know, our boat batteries are knackered (soon to be replaced hopefully - the funds are nearly in place). We tried running the TV via our 150 watt inverter yesterday, within about a minute the inverter started squealing, then shut down, so we know that's not going to work without the engine running.

 

Dave went to Maplins today to see if he could get a regulated DC power supply unit, similar to the one we use for the laptop (we'd been very careful to buy a 12 volt TV). The one we use for the lappy only goes down as far as 15 volt, so that's no good. The only 12 volt to 12 volt unit he could find was 4.5 amps, the TV is 5 amps.

 

Can't be bothered to read the whole thread so apologies if someone has said this;

 

the overhead for the inverter will be around 10%, the overhead for the DC PSU though less will still be there and it is not the PSU or inverter that is causing the stress on your batteries it is the TV.

 

Whereas a 12V PSU is going to be a bit more efficient (maybe) the improvement worthwhile in the longer term is not your current problem.

 

While the TV is on warranty, try plugging it straight into your boat's electric - if it goes pop take it back. I really cannot see the point of 12V to 12V converters unless you have very sensitive and expensive equipment.

[Pretty Funked Up]

Well, at the risk of possibly placing a cat amongst the proverbial pigeons... I would dare to suggest that the device requiring a.c. may actually work fine on a diet of d.c. -- this is because the first thing that it may do with the input is pass it through a bridge rectifier and turn it into d.c. so it can work with it....

 

Nick

 

I'll 2nd this, 12vdc will be fine. The psu putting out 12vac is a cost cutting thing springing up more n more now.

 

diff note- gotta say thats one hungry tv!! perhaps shopping around for better screen might be wise

[Ange]

Wow - new batteries!

 

Watched "A Passionate Woman" on our TV without the engine running - no shrieks or wails from the invertor!

 

It seemed like a little piece of magic waching an hour of TV tonight

 

(Thanks to Vince1969 who supplied the batteries at £25 each)

[churchward]

Alan - thanks for the suggestion - we'll definitely look into that (I'll follow the linky when I next borrow someone's wifi - my dongle is behaving badly today!) We only watch about an hour of TV per day so we're definitely not heavy users.

 

Ditchcrawler - I wish the TV had come with a 12volt lead to plug into the cigarette lighter connection! The TV is 12 volt but we bought it from Currys and it's only designed for house use, so only has a 240 volt lead, with a 12 volt psu. Unfortunately our batteries / invertor can't cope (I had the same problem with my laptop when we first moved aboard)

 

Nick - thanks for the offer. I've got Dave helping me now cos this has gone way over my head! We've got a 70 watt adaptor which ranges from 15 - 24 volt, do you think this would be powerful enough with your modification, or should we buy a 120 watt adaptor?

 

Is there a chance of damaging the TV? (It's an JVC LCD).

 

I'm fighting with a wayward dongle tonight so may have to pick this up again tomorrow (I can feel a night of Wetherspoons wifi and cheap beer looking very attractive tomorrow!)

 

Edit for double post - bah!

 

 

We use the Amperor power regulator and it works just fine for us. As Alan says some folk seem to be able to get away with using the 12V supply direct but I am happier using the device as it is good insurance against damaging the TV.

[cheshire~rose]

Wow - new batteries!

 

It is a wonderful feeling isn't it Ange?

 

I know the batteries on Carrie~Lou had been kaput (probably on their last legs for at least a year ) and we had got used to being really frugal with power and yet wake up every morning knowing there was no power left to even run the fridge until the engine had been run. Since we replaced them last autumn we don't know we are born!

 

Remember to check the water levels on those new batteries at least once a month - ours took some topping up to start with but it seems to have settled down now.

[Gibbo]

Well, at the risk of possibly placing a cat amongst the proverbial pigeons... I would dare to suggest that the device requiring a.c. may actually work fine on a diet of d.c. -- this is because the first thing that it may do with the input is pass it through a bridge rectifier and turn it into d.c. so it can work with it....

 

However, I couldn't recommend you try it without looking at the circuit diagram ( if available - unlikely - or the circuit board itself and seeing what the path is that it follows, and going through what components. One slight advantage of something saying it requires 12 volts a.c. is that it actually needs only about 9.6 volts after a bridge rectifier pack, and the polarity " doesn't matter " as the diode pack will cope with that by presenting the electronics with the correct polarity after the rectifier pack. Only a couple of days ago did I need to find another psu for a failed one powering a hub here at home, and this was just the scenario, so I gave it 7.5 volts d.c. instead of 7.5 volts a.c. and all was working a few mins later - it actually worked on 6 volts d.c after the bridge rectifier pack.

 

Nick

 

Wrong way round Nick.

 

An item that requires 12 volt AC would be relying on that 12 volts AC being internally rectifed which would give about 16 to 17 volts DC. So it would need 16 to 17 volts DC to be plugged into it.

[WotEver]

An item that requires 12 volt AC would be relying on that 12 volts AC being internally rectifed which would give about 16 to 17 volts DC. So it would need 16 to 17 volts DC to be plugged into it.

Assuming full wave rectification

[Gibbo]

Assuming full wave rectification

 

 

Think about that again. Then look for the "whoops" smiley

[Nickhlx]

Wrong way round Nick.

 

An item that requires 12 volt AC would be relying on that 12 volts AC being internally rectifed which would give about 16 to 17 volts DC. So it would need 16 to 17 volts DC to be plugged into it.

 

 

Course it is - these drugs are doing my head in ! For some reason I was thinking that the first device would be a bridge rectifier so input was not polarity sensitive and it was DC being supplied - I've just been repairing a "7.5V a.c. input" hub where this is the case - the wall wart is an "unregulated 7.5 v a.c." device putting out around 10 V with no load and dropping as the load increases - it actually works from 6 V dc - presumably TTL devices within...

 

Nick

[WotEver]

 

Think about that again. Then look for the "whoops" smiley

Guess this one will have to do

[Gibbo]

Guess this one will have to do

 

We're all human.

 

Well.... most of us

 

Course it is - these drugs are doing my head in ! For some reason I was thinking that the first device would be a bridge rectifier so input was not polarity sensitive and it was DC being supplied - I've just been repairing a "7.5V a.c. input" hub where this is the case - the wall wart is an "unregulated 7.5 v a.c." device putting out around 10 V with no load and dropping as the load increases - it actually works from 6 V dc - presumably TTL devices within...

 

Nick

 

Ditto.