MORE HELP NEEDED ON TRANSFORMERS !?!?!

[respec24]

I am installing 6 sofit lights across my front roofline, but i am having problems working out whats what with the transformer i have bought (PRI:220~240vac 50Hz 25VA SEC:12vdc 1.67A Max.20VA) with its funny block connctor for each individual light ?!

I just want to run from the first to last light with no 'loop or return wire, just like the 2 packs of LED garden lights i have just discovered in my garage ! 2 packs of 3 LED mini posts & each with a 12V 840 mA 10.08va transformer. So if one transformer will feed all 6 garden light posts then i have 1 spare transformer for this project !! And it simply plugs in & has a 2 pin output port ! Wow please say this transformer will work !!! Is it the solution to all my problems !?

Like most people Amps, Ohms, Volts etc etc are another language !

I have also found a transformer marked - "12~3A 36va" ??

Also i do have a fair run, furthest light is 15 feet up & then 25 feet across i think, will this mean i need an LED driver or more Amps, current, flow or something ? Is 1.5mm2 lighting cable too heavy ? If the above transformers are no good & i return my origional "funny" transformer, what transformer do i need or should i just revert to mains !? I have forgotton now why i bothered with 12v in the first place !!

 

[Taylortwocities]

In your case you can regard "VA" to be the same as watts (W).
You do not say what wattage your soffit lights are, please tell us and that will help greatly!

The 25VA transformer that you have will drive only one 20W halogen light.
Basically, add up all of the light wattage (eg 6 x 20 watt lights = 120 watts) then go buy a transformer that is at least as big as the total.

Use heavy guage wire if you are wiring the lights up as a chain otherwise the last light will be a lot dimmer than the first one.

Hope this helps

 

[respec24]

My 6 lights are just 1w LED GU10 spot lights, & i would like them all as bright & equal as possible ! I have bought in 1.5mm2 lighting cable ?

 

[Taylortwocities]

Have a look at your lamps. If they are GU10 then they should say 230v on them. If so then you do not need a transformer at all.
AFAIK GU10 is a 230v lamp.

 

[Steve]

Given such a light load, voltage drop wouldnt really be an issue would it? (respec has just personally emailed me with the problem too)

The connector block is the type that comes on kit tx's, with about 6 sockets on it for pre-formed leads. Advised him to snip this off if he has no other use for it.

 

[Taylortwocities]

Yes but he didnt reveal the 1watt (and GU10) bit until later in the thread.

I also got a PM but my filter bunged it straight into junk email - where it belongs. I'll only respond on the forum else my inbox is full with what i dont want.

 

[breezer]

I dont think its fair / polite to ask members directly via email a question that should be asked / debated on the forum

 

[respec24]

Sorry lads no offence intended, just my old post went cold & you know whats what, I won't do it again

 

[Taylortwocities]

None taken.

Are you sorted wrt the lights now then? What was the solution?

 

[respec24]

Hi, thanks for your help & patience & sorry for e-mailing any personal accounts. I am still confused but getting there ! -

My bulbs are 6 x 12v, 1w LEDs & GU10 casings 12v. It does not say if they are AC or DC ??? So i need a 12v, 6 VA minimum transformer, but what about Ampage ??? These are the 3 Transformers i have at the moment -

1 - 12v DC 1.67A max 20va
2 - 12v "AC adapter" 840 mA 10.08va
3 - 12v 3A 35va (& 3 funny symbols) - How can i determine if AC or DC ??

So i guess all would easily supply the required 6W power at 12v. But there is a huge difference in Ampage. Is 1MA one thousanth of 1A ???
Also does AC adapter mean is supplies AC current ?
What is the perfect dream match ? 6VA ? What A ? Does a higher VA or A mean brighter LEDs or life ? Can anyone unlock the meaning ?!

What guage wire should I use ? I don't want any fire risk & was going to mount the transformer in side the garage in the 100% dry. If i use a plug in transformer then i would have to use the photocell sensor switch to make to actual socket turn on & off ??

 

[electronicsuk]

My bulbs are 6 x 12v, 1w LEDs & GU10 casings 12v. It does not say if they are AC or DC ???

If they don't claim to be either than nobody can give you an answer for sure, my assumption would be that they contain a bridge rectifier and will run off either AC or DC. If you want to be safe then run them on 12v DC, if that doesn't work then switch to an AC supply.

So i need a 12v, 6 VA minimum transformer, but what about Ampage ??? These are the 3 Transformers i have at the moment -

1 - 12v DC 1.67A max 20va
2 - 12v "AC adapter" 840 mA 10.08va
3 - 12v 3A 35va (& 3 funny symbols) - How can i determine if AC or DC ??

Yes, all these transformers will supply more than enough power for the fixtures you have. Out of those you have listed I would choose #1 on account of it being the only confirmed DC supply on the list. You can test #3 by getting a multimeter set on the 20v AC (or thereabouts) range and then putting the test probes across the transformer output. On a DC supply the meter will read briefly and then show nothing, on AC you'll get a constant reading of ~12v.

So i guess all would easily supply the required 6W power at 12v. But there is a huge difference in Ampage. Is 1MA one thousanth of 1A ???
Also does AC adapter mean is supplies AC current ?
What is the perfect dream match ? 6VA ? What A ? Does a higher VA or A mean brighter LEDs or life ? Can anyone unlock the meaning ?!

Yes, 1mA = 1/1000th of an Amp. The term AC adaptor is quite widely used and in my experience refers to any power adaptor that runs off the mains supply.

There is no 'perfect' match for your lamps, as long as the transformer is >6VA then there will be no merit in using a larger transformer. Just so you know, 6VA / 12v = 0.5 Amps.

Transformer selection CAN be important in some circumstances when using LEDs, as some types are designed to be driven from a constant current supply and will simply draw all available power and destroy themselves if run off the wrong transformer. I assume these aren't the type you have, as it would be clearly stated on the instructions if that were the case, not to mention I've never seen this type in GU10.

What guage wire should I use ? I don't want any fire risk & was going to mount the transformer in side the garage in the 100% dry. If i use a plug in transformer then i would have to use the photocell sensor switch to make to actual socket turn on & off ??

Even bellwire will do the job in this case, it's only 500mA after all. I'd use 3A lamp flex to try and keep volt drop as low as possible How the photocell is fitted depends on the type you purchased.