I am looking for a AC Adaptor

Model: JT-12V3000
Input: 230-240v AC 50Hz
Output: 12VAC 3000mA Max: 36Va

It is for the lights in my garden i have two lots and after switching
it all around it appears one of my AC adaptors is broken. I have google
searched but have no idea where to get one from the connection from the
lights is a small two pin.

Any help/Suggestions greatly appreciated.

wrote:

I am looking for a AC Adaptor

None of the off the shelf ones from Maplin are beefy enough to replace
that, really it looks like all the original adapter is, is a cased
transformer ...

Andy Burns wrote:
wrote:

I am looking for a AC Adaptor

None of the off the shelf ones from Maplin are beefy enough to replace
that, really it looks like all the original adapter is, is a cased
transformer ...

How about hacking up an old car battery charger?

--
Adrian C

I wrote:

How about hacking up an old car battery charger?

ohhhh.... forget that - probably be made to output at a higher voltage....

--
Adrian C

Adrian C wrote:
I wrote:

How about hacking up an old car battery charger?

ohhhh.... forget that - probably be made to output at a higher voltage....

--
Adrian C

Is Adrian C the forum comedian? dont give up the day job eh!?!

wrote:
Adrian C

Is Adrian C the forum comedian? dont give up the day job eh!?!

Ha! Thought that would come upon me one day...

Fame at last ;-)

--
Adrian C

I think its only "AC" as AC adaptors are cheaper than DC - lights work just
as well off AC as DC unless there are things like triacs (dimmers or
electronic switches) involved which is probably not the situation in your
application.... so that opens up the options a bit....

Anyway, to my point....Aldi (maybe Lidl) have a 13 volt 5 amp DC ( 65 watt)
adaptor coming up soon at about a tenner and Ithink this might have been for
low voltage lighting as well and this would give you a tiny bit more voltage
to counter line losses and plenty in reserve.

I am going to get one, even though I haven't a use for one at the moment, as
this seems a useful buy....

Anyone comment about line / load regulation and the AC / DC issue?

Hope that helps,

Nick

Nick wrote:

I think its only "AC" as AC adaptors are cheaper than DC - lights work just
as well off AC as DC unless there are things like triacs (dimmers or
electronic switches) involved which is probably not the situation in your
application.... so that opens up the options a bit....

Anyway, to my point....Aldi (maybe Lidl) have a 13 volt 5 amp DC ( 65 watt)
adaptor coming up soon at about a tenner and Ithink this might have been for
low voltage lighting as well and this would give you a tiny bit more voltage
to counter line losses and plenty in reserve.

I am going to get one, even though I haven't a use for one at the moment, as
this seems a useful buy....

Anyone comment about line / load regulation and the AC / DC issue?

Hope that helps,

Nick

filament lamps dont care what you feed them as long as the rms voltage
is right. 13v or 13.6v on 12v bulbs is too high and will lead to short
bulb life. Filament bulbs are fussy about that.


NT

filament lamps dont care what you feed them as long as the rms voltage
is right. 13v or 13.6v on 12v bulbs is too high and will lead to short
bulb life. Filament bulbs are fussy about that.


NT

Hi,

Thanks for the reply - been trying to find out what voltage car "12 volt"
bulbs are actually designed to work at and
wondered if you knew ?

With alternators producing voltages variously around / between 13.8 and 14.0
V DC (and that is plus or minus tolerances !) which don't seem to blow car
bulbs too often, I wonder if they are actually "nominally 12 volts but
actually designed for 13.8" or the tolerance is actually quite wide.

Thanks,

Nick

"John Weston" wrote in message
.. .
Nick, in article ,
says...

Thanks for the reply - been trying to find out what voltage car "12 volt"
bulbs are actually designed to work at and
wondered if you knew ?

12.0V across a battery indicates there is only around 30%
charge remaining. Fully charged, it is around 12.8V (see:
http://www.adverc.co.uk/technical/technical-soc.asp)


With alternators producing voltages variously around / between 13.8 and
14.0
V DC (and that is plus or minus tolerances !) which don't seem to blow car
bulbs too often, I wonder if they are actually "nominally 12 volts but
actually designed for 13.8" or the tolerance is actually quite wide.

Alternators regulators can control the output to around 14.4V,
or more at low temperatures, to charge the battery in a
reasonable time if it is deep discharged. Car alternator
regulators are designed to clamp the voltage at 14.2V +/-
0.4V. Ordinary filament lamps cope with this (OK, at a reduced
life) whereas, for example, a LED lamp must have something to
accommodate the voltage swing without the battery +
alternator driving too much current through it.
--
John

Hi John,
Thanks for the reply ...

I had thought that around 13.8 to 14.0 was the "target area", and the "12
volt" bulbs were actually designed to work at about 13.0 volts after taking
into account the various losses in the cabling, connectors switches etc.

I do usually fit heavier wiring via heavy duty relays to the headlamps on my
vehicles ( halogen bulbs) and this results in a reduction of the volt drop
of around 1 volt or a bit over - the extra whiter light is quite noticeable
and I don't seem to change bulbs any more often.

I would have thought LED lamps at 12 volts with limiting resistors say for
15 mA, would not worry at all if 14 volts appeared and they then were
getting around 18 mA or so passed through them - just a touch brighter -
many have a max continuous current of 30 mA or more - and some are pulse
driven at much higher currents from a regulated source..

Anyway, it is interesting to read that car voltages are apparently a bit
higher than I had thought..

Thanks for the reply

Nick

In article ,
Nick wrote:
With alternators producing voltages variously around / between 13.8 and
14.0 V DC (and that is plus or minus tolerances !) which don't seem to
blow car bulbs too often, I wonder if they are actually "nominally 12
volts but actually designed for 13.8" or the tolerance is actually
quite wide.

Most car bits are designed to work at 13.8v as this is the voltage that
the alternator 'settles' to.

--
*Bigamy is having one wife too many - monogamy is the same

Dave Plowman London SW
To e-mail, change noise into sound.

In article ,
John Weston writes:

Alternators regulators can control the output to around 14.4V,
or more at low temperatures, to charge the battery in a
reasonable time if it is deep discharged. Car alternator
regulators are designed to clamp the voltage at 14.2V +/-
0.4V. Ordinary filament lamps cope with this (OK, at a reduced
life) whereas, for example, a LED lamp must have something to
accommodate the voltage swing without the battery +
alternator driving too much current through it.

Filament lamps in cars don't need a long life anyway.
The operating life of a car is only around 3000 hours
(that's the figure manufacturers tend to use when specifying
the required life of parts which they don't normally expect
to have to replace during the lifetime of a car). Most lamps
used in cars operate for only some small portion of the time
the car as a whole operates. IME, headlamps are the main
lamps which routinely fail, and even then, I've probably
only gone through about 4 bulbs in nearly 100,000 miles,
which is probably about 3000 hours. However, they are only
used a small part of this, perhaps 25%, so we're looking
at a lamp life of something in the order of 250 hours.
Things like dashboard lamps are probably well underrun
in comparison to headlamps, and if they have a life of
1000 hours, chances are you are not going to see any
failures during the life of the car (and I haven't).

--
Andrew Gabriel

Nick wrote:
"John Weston" wrote in message
.. .
Nick, in article ,

Thanks for the reply - been trying to find out what voltage car "12 volt"
bulbs are actually designed to work at and
wondered if you knew ?

yep, wot e said. They will run at alternator output voltage minus
wiring Vdrop, which is well above 12v. 12v car electrics are not 12v.

NT