How hot?

[bag 'o' bones]

Wired the TV up for 12 volt today.

 

I've run a cable from the spare switch on the distribution board to a fag lighter socket behind the tv. Plugged into this is a 12 volt regulator brick which then plugs into the TV.

 

Thing is the brick is getting VERY hot even after a few minutes to the point it would probabally ment if left for a long period.

 

I havn't tested the voltage at the socket with a test meter as yet but according to the distribution dial it was showing just over 12 volt which I beleive is a normal for an unregulated circhuit.

 

Any thoughts? Duff regulator brick or fault with the wiring?

[Nickhlx]

Wired the TV up for 12 volt today.

 

I've run a cable from the spare switch on the distribution board to a fag lighter socket behind the tv. Plugged into this is a 12 volt regulator brick which then plugs into the TV.

 

Thing is the brick is getting VERY hot even after a few minutes to the point it would probabally ment if left for a long period.

 

I havn't tested the voltage at the socket with a test meter as yet but according to the distribution dial it was showing just over 12 volt which I beleive is a normal for an unregulated circhuit.

 

Any thoughts? Duff regulator brick or fault with the wiring?

 

 

To me, it definitely shouldn't be getting that hot - is the consumption being drawn within the rating of the brick ? I.e. are you trying to e.g. draw 4 amps from a 3 amp rated device ?...

 

But what does this "brick" do ? Does it convert 12 volts from the cigar socket to mains for the TV ( same query... is the rating of the "brick" ( invertor) adequate for the power being demanded).

 

 

Nick

Edited May 21, 2011 by Nickhlx

[by'eck]

Not sure why you need a regulator brick. Have never run any "12 volt" device other than direct from battery system (via switches breakers etc.). They all seem to cope with anything between 11.5 & 14 volts being designed to run from car or truck systems.

[Nickhlx]

Not sure why you need a regulator brick. Have never run any "12 volt" device other than direct from battery system (via switches breakers etc.). They all seem to cope with anything between 11.5 & 14 volts being designed to run from car or truck systems.

 

 

That was my thinking - only device I have used between the "12 volt" boat supply and the "12 volt" input of e.g. the TV, is spike arresting gizmos, but they don't alter the voltage of the supply ...

 

So what is this "brick" device supposed to be doing ? I can't think it is a 240 volt a.c to 12 volt DC converter

 

 

Nick

[dor]

I presume this is an Amperor-type voltage stabiliser.

 

It certainly shouldn't be getting that hot.

 

If you are only measuring just over 12V at the distribution panel, then you are likely to be well below 12V at the socket. Perhaps the 'brick' can't cope with the low input voltage and is trying too hard to stabilise the voltage.

 

"Just over 12V" at the battery is effectively flat.

[bag 'o' bones]

I presume this is an Amperor-type voltage stabiliser.

 

It certainly shouldn't be getting that hot.

 

If you are only measuring just over 12V at the distribution panel, then you are likely to be well below 12V at the socket. Perhaps the 'brick' can't cope with the low input voltage and is trying too hard to stabilise the voltage.

 

"Just over 12V" at the battery is effectively flat.

 

Yes its a an Amperor style brick designed to stabilise the 12 volt power supply and prevent damaging spikes. It can cope with inputs between 10 and 30 volt according to the specifications.

 

The brick is rated up to 5amp the TV is 4 amp.

 

I think you could right about the batteries being a bit flat but even then I wouldn't have though it would cause the brick to heat up excessively.

 

Think i'm going to send them an e-mail before I do anything else.

[ditchcrawler]

Are you suffering from excessive volt drop on your new wiring and ciggy lighter plug/socket?

[bag 'o' bones]

Are you suffering from excessive volt drop on your new wiring and ciggy lighter plug/socket?

 

I used 27amp wire to match the heaviest gauge wire on the boat which is supposed to prevent voltage drop. The circuit is so simple it would be hard to get something wrong.

Edited May 22, 2011 by bag 'o' bones

[Josh]

Is this a cheap unit? i.e a cheap Chinese and crap or, recently; cheap Indian and crap.

 

5A could be right on the thermal limits of the design; just how hot is it? Can you keep your hand on it for 45 seconds or so?

 

 

Josh

[Gibbo]

I used 27amp wire to match the heaviest gauge wire on the boat which is supposed to prevent voltage drop. The circuit is so simple it would be hard to get something wrong.

 

This could be the root of the problem. How long is the cable run?

[WotEver]

I used 27amp wire...

What does that mean? 2.5mm? For any length of run I'd be using at least 6mm cable for this.

 

Tony

[Nickhlx]

What does that mean? 2.5mm? For any length of run I'd be using at least 6mm cable for this.

 

Tony

 

 

Our boatbuilder, from the rear / engine bay where the batteries are, to the fridge/galley area about half way up ( 25 feet or so) used 25mm^2.. In fact all the wiring was done in a very "non-skimping" way - most impressed...

 

Nick

[WotEver]

Our boatbuilder, from the rear / engine bay where the batteries are, to the fridge/galley area about half way up ( 25 feet or so) used 25mm^2.. In fact all the wiring was done in a very "non-skimping" way - most impressed...

 

Nick

Excellent practice

 

Tony

[Gibbo]

What does that mean? 2.5mm? For any length of run I'd be using at least 6mm cable for this.

 

This was my thinking. The poor little power pack could be straining its nads off trying to get 8 volts or something up to 12.

[WotEver]

I was actually thinking about my 6mm as a minimum and wondering if I should have said 10mm...

[pistnbroke]

DOR where does this " if its only 12v ist effectively flat" come from ? If its under load then its not flat till it reads 10.8v but if its been charge and stood 24 hrs below 12.5 means its suspect .... I understand but do 98 % of forum readers understand your misleading comment ....

[Nickhlx]

DOR where does this " if its only 12v ist effectively flat" come from ? If its under load then its not flat till it reads 10.8v but if its been charge and stood 24 hrs below 12.5 means its suspect .... I understand but do 98 % of forum readers understand your misleading comment ....

 

 

I assumed he meant "at rest" voltage - voltage on load or on charge is fairly meaningless if you are trying to ascertain SOC

 

Nick

[bag 'o' bones]

27amp wire =

 

44/0.3

 

3mm core.

 

I think voltage drop might be an issue.

[Gibbo]

How long is the cable run?

[bag 'o' bones]

How long is the cable run?

 

18 metres to the tv and back.

 

according to Tony Bookes voltage drop table:

 

the voltage drop for 27amp (44/0.3)wire is 0.0062 volts per metre

 

therefore:

 

0.0062 x 4.5 amps (TV) x 18 metres = 0.522

 

= a drop of .5 volts rounded

 

Hopefully that right!

[Gibbo]

Hopefully that right!

 

Yep that's right. So I don't think it's that. So we got nowhere

[Sir Nibble]

In a faglighter socket. Crap connectors them, get hot.

[Nickhlx]

In a faglighter socket. Crap connectors them, get hot.

 

 

Certainly do with a cigar lighter in them !!

 

Nick

[bag 'o' bones]

Is this a cheap unit? i.e a cheap Chinese and crap or, recently; cheap Indian and crap.

 

5A could be right on the thermal limits of the design; just how hot is it? Can you keep your hand on it for 45 seconds or so?

 

 

Josh

No idea. bought it for 25 quid from a 12 Volt TV supplier. Temperature could be described as 'uncomfortable' if you were to hold the brick for any length of time.

 

Yep that's right. So I don't think it's that. So we got nowhere

 

Thats what I though. Reading the blurb it appears that 3mm wire is at the limit and the next wire size up would have been more ideal. But even then I wouldn't have thought a .5 volt drop would cause a switch mode (I assume) converter to heat up to such an extent. Assuming that the brick is of resonable quality from what I have read switch mode supplies are in the 90's% for efficiency so one would expect the unit to run as least as cool as a lap-top mains power brick?

 

In a faglighter socket. Crap connectors them, get hot.

 

The faglighter socket is a Maplin jobbie. Its meant to be a temporary until decide on what 12 volt sockets to use.

[WotEver]

Assuming that the brick is of resonable quality from what I have read switch mode supplies are in the 90's% for efficiency so one would expect the unit to run as least as cool as a lap-top mains power brick?

Can you get at the back of the socket with a multimeter to read what voltage is actually going into the thing?

 

Tony