12 v 230 volt spot lights

[ericmark]

Looking at Steve and RF Lighting post over energy used to power down lights has got me thinking and I did not want to confuse xspurt (Is that a drip under pressure!).

So if we compare 12 volt and 230 volt small spot lights each seems to have a few advantages.

In theory when powering 12 volt units from an inverter it should be able to correct any voltage fluctuations and give a constant voltage. But this would only be true with inverters and with transformers there would be no advantage. Also with inverters if they were designed to correct any voltage fluctuations then they would not work with dimmer units and many do.

Maybe the inverters can read the difference between a chopped supply and a low peak voltage but I am not convinced!

Also I know with many positive and negative chopping and post and pre peak chopping of wave form need to be matched so it is hard to fit dimming units latter because one needs to find matching dimmer.

Yes I know you should never dim quartz lights as they will have much reduced life but never the less many people do fit them.

Unlike the 230 volt version both dichroic fit into same holder and also there is a problem with overload where 50W lamps can be fitted into systems only designed for 10W and either this will cause the inverter/transformer to shut down or burn out.

However the GZ10 and GU10 are not perfect either being reliant on correct voltage and there seems to be loads of low quality units on the market which means they need changing far too often.

They do however have a better electrical connection.

Both extra low and low voltage have LED versions but with extra low voltage some of the inverters will not allow them to be used as below min volts and with low voltage (230) they tend to be longer and stick out of the holder.

Cold cathode or florescent versions seem to be limited to the 230 volt version again physical longer.

The quartz halogen because of the hotter light and reflector in theory they are suppose to be more energy efficient than normal bulb. This of course relies on correct fitment and replacement. With angles of 10°, 24°, 36°, 60° and wattages from 10 to 75 even if originally selected with care once a few bulbs have been replaced it is unlikely to still be set up correctly.

With all these, variation I still cannot see how anyone with hand on heart can say using a transformer and extra low voltage lamps with loses can be better than the 230-volt low voltage lamps.

However where we need low voltage because of safety then of course the 12 volt SELV lamps have a distinct advantage. Also because some low voltage inverters/transformers will auto shut down if the bulb is too big where heat is a problem they also have some advantages but this is not so good as there is no SELV equivalent of the selective properties of the GZ10 and GU10 where dichroic lamps will to physical fit the GU10 holders.

If we were to take a single make of both lamps I am sure we could show some advantages with the SELV 12 volt versions but once fitted the chances of only a like for like replacement is slim. The same goes for the Low voltage 230 volt versions I have heard many complain about how quickly the lamps blow but when you inquire they bought the cheapest of cheap replacements and don’t seem to understand why a £5 lamp lasts longer than a £1 for 3 lamp. Yes I know not 15 times longer but to replace every couple of weeks is a pain but once every 6 months is acceptable.

There will be the odd premises who suffer from over voltage and need good quality inverters to smooth out these and as a result will find 12 volt lighting better and also bathrooms where 12 volt lighting must be an advantage but in the main I see no real advantage in using a 12 volt system.

So gauntlet is down show me I am wrong.

 

[Steve]

The only real "advantage" is that ELV lights produce better quality light, but to we humans, its not noticeable.

LV however, can be fitted with CFLs, have one less component to go wrong, and four less terminations to go wrong.

 

[seasickstevie]

Over our breakfast table, we've got three ELVs on one switch, and four GU10s on a second switch (all 50w).

It's fairly obvious (to me, although no-one else notices) that the ELVs are brighter.

 

[sparkyspike]

It's obvious to me that ELVs are brighter and whiter. At the moment I have ELVs on one side of my kitchen and LVs on the other (I've just extended the kitchen and haven't taken down the old LV spotlights yet). The difference is really easy to see.

 

[RF Lighting]

The only real "advantage" is that ELV lights produce better quality light, but to we humans, its not noticeable.

Should've gone to specsavers


But seriously, I can tell the difference immediately. Maybe I've spent too long working in the trade?

If installed properly, you will get a very long life from ELV lamps. I've had some in two rooms at home (11 in total) for about 7 or 8 years now, and never had so much as a failed lamp.

 

[blondini]

The filaments in 12v lamps are thicker and more robust than their 230v equivalents. This makes them last longer.

If the transformer supplying 12v lamps has a soft start, this will also make them last longer.

When a 12v lamp does fail it is less likely to trip the MCB as the transformer will mask the surge.

 

[ericmark]

It's obvious to me that ELVs are brighter and whiter. At the moment I have ELVs on one side of my kitchen and LVs on the other (I've just extended the kitchen and haven't taken down the old LV spotlights yet). The difference is really easy to see.

Are the lamps of same make? Are they claimed to be same colour temperature. If so interesting. My camera will register light and colour and I will try to compare some tomorrow

 

[ban-all-sheds]

But basically it all comes down to the equivalent of saying that a Landcruiser Amazon is better than a Range Rover Vogue because it does 17mpg whereas the RR only does 15....

 

[blondini]

This is enlightening http://www.wiki.diyfaq.org.uk/index.php?title=Halogen_Lighting

 

[ericmark]

I took 4 pictures of spot lights through a old VCR box to reduce and defuse light.
The 50W SELV Was 1/750 second at F9.5 and showed as being very much a spot lamp the colour balance being very much to the left of graph.
The 50W GU10 Was 1/180 second at F8 so no where near as bright but also the spread of light was far greater and colour balance more to the centre of graph.

This as BAS said really means one can not compare very well.

While at it I also checked 11W cold cathode lamp 1/90 second at F5.6 soon after switch on it was also tight to left on light spectrum graph and quite a tight spot even 5 minutes latter not much better.

So the SELV was brighter but because it was more of a spot and the camera is centre weighted when I backed away from the lamp to get same spread as GU10 I got 1/90 at F5.6 so to illuminate for example a picture the GU10 would be better than the SELV as better colour and better spread when close. Even with SELV lamps on ceiling one can still see defined spot on the floor if over 2 meters apart where the GU10 has to be double that distance before you can see spot of light on floor so even for general lighting better.

However for lighting the dart board then SELV would be far better being able to mount well out of the way of the darts.

The wikipedia entry was interesting but since it talks about inverter supplies those like me with a plain transformer are not likely to get same benefits.

I think a lamp manufactures web site would be more reliable but as yet not found one.

 

[ericmark]

To left Technical Data for Osram Decostar 51 IRC 50W Energy Saving Halogen Light Bulb
To right Technical Data for Osram Halopar 16 50W GU10 Flood Halogen Light Bulb
Average Life ----------5000h------------1000h
Beam Angle -----------36 °--------------Not given
Cap Type---------------MR16(GU5.3)---GU10
Colour Temperature---3000K-----------2900K
Diameter----------------50 mm----------50 mm
Dimmable---------------Yes--------------Yes
Lamp Type--------------Halogen---------Halogen
Length-------------------45 mm----------55mm
Standard Wattage
Equivalent---------------65W------=------Not given
Voltage------------------12V--------------240V
Wattage Max------------50W-------------50W
WEEE-------------------- No-------------- No
Price---------------------£3.21-----------£1.53
So it seems by time you add transformer price the MR16 is far more expensive but last longer and are whiter than the GU10 all info from Osram web site.