PowerSwitch Main Page
PowerSwitch
The UK's Peak Oil Discussion Forum & Community
 
 FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 

Domestic 12V lighting

 
Post new topic   Reply to topic    PowerSwitch Forum Index -> Electrical, Theory and Practice
View previous topic :: View next topic  
Author Message
clv101
Site Admin


Joined: 24 Nov 2005
Posts: 7636

PostPosted: Fri Nov 25, 2016 8:59 pm    Post subject: Domestic 12V lighting Reply with quote

LEDs are clearly superior to compact fluorescence bulbs, producing more lumens per watt, having a longer life and not containing hazardous materials. However, LEDs are low voltage, DC devices so LED bulbs designed for regular 230V fittings have little transformers in them - adding cost and reducing reliability. It seems more sensible to run a 12V lighting circuit in a house.

Looking at professional LED lighting designs though there seems to be a lot of 'rebound effect' going on. Their efficiency being squandered by using multiple, often obscured lighting 'features'.

In my small wearedodgy I have a single 6W LED filament bulb (the filament bulbs are a special case of many LEDs in series along the 'filament' so they need high voltages). This is a perfectly good enough light. However it's not obvious that such practical and efficient solutions are available from 12V DC bulbs. There are lots of halogen replacement spots... but at 2-3W a piece, by the time you've lit a decent sized room you might be looking at 20W at least and when thinking about several rooms, voltage drop / cable cost becomes an issue.

Any ideas for efficient 12V LED lighting solutions for domestic setting?
_________________
PowerSwitch on Facebook | The Oil Drum | Twitter | Blog
Back to top
View user's profile Send private message Visit poster's website
adam2
Site Admin


Joined: 02 Jul 2007
Posts: 6220
Location: North Somerset

PostPosted: Fri Nov 25, 2016 10:55 pm    Post subject: Reply with quote

There are now some very good LED "filament" lamps in 12 volts.

I have several, and they seem to be good quality. Unfortunately the supplier I used has no stock at present.

I also purchased from the well known tax avoiding outlet Embarassed but these seemed to be of lower quality and appear to flicker at about mains frequency, which is clever of a lamp with a DC supply.

Numerous suppliers offer low power non directional LED lamps for 12 volt DC supplies.
_________________
"Installers and owners of emergency diesels must assume that they will have to run for a week or more"
Back to top
View user's profile Send private message
kenneal - lagger
Site Admin


Joined: 20 Sep 2006
Posts: 9822
Location: Newbury, Berkshire

PostPosted: Sat Nov 26, 2016 5:33 am    Post subject: Re: Domestic 12V lighting Reply with quote

clv101 wrote:
....................There are lots of halogen replacement spots... but at 2-3W a piece, by the time you've lit a decent sized room you might be looking at 20W at least and when thinking about several rooms, voltage drop / cable cost becomes an issue. ......


This just highlights the stupidity of using a dozen or more spotlights to area light a room. The sooner this ridiculous architectural fashion bites the dust the better!

Why use a dozen spots when a couple of pendant lights will do. We use a couple of pendants for every day use in our living and dining rooms and then we have, on a separate switch, four up lighters for occasional mood lighting. The four up lighters have the same bulbs in as the pendants but give about half the useful light! We don't use them very often.
_________________
"When the last tree is cut down, and the last river has been poisoned, and the last fish has been caught, Only then will you find out that you cannot eat money". --The Cree Indians
Back to top
View user's profile Send private message Send e-mail Visit poster's website
adam2
Site Admin


Joined: 02 Jul 2007
Posts: 6220
Location: North Somerset

PostPosted: Sat Nov 26, 2016 12:30 pm    Post subject: Reply with quote

This fleabay supplier have sold 12 volt LED "filament" lamps.
Out of stock at present, but presumably they will get more in ?

Note that they have a complex multi listing and that most of the lamps are either mains voltage, or narrow beam spotlights.

The ones that I purchased are 4 watts, claimed 400 lumens, E27 base, warm white, and work from supplies of 10 volts up to 30 volts, DC only.
Replacement stock may be of a different specification.

The wide voltage range permits of operation from 12 volt or 24 volt nominal systems, or indeed from 16 volt systems if anyone still uses 16 volts.

http://www.ebay.co.uk/itm/12V-24V-230V-LED-Lightbulb-E14-E27-G4-MR16-GU5-3-Spotlight-220V-/112113676020?var=&hash=item1a1a7eeef4:m:m3zNZd6rlwl72crEueKfvsQ
_________________
"Installers and owners of emergency diesels must assume that they will have to run for a week or more"
Back to top
View user's profile Send private message
kenneal - lagger
Site Admin


Joined: 20 Sep 2006
Posts: 9822
Location: Newbury, Berkshire

PostPosted: Sat Nov 26, 2016 5:26 pm    Post subject: Reply with quote

Would the light output from those lamps be less from 12V than from a 24V system, Adam?
_________________
"When the last tree is cut down, and the last river has been poisoned, and the last fish has been caught, Only then will you find out that you cannot eat money". --The Cree Indians
Back to top
View user's profile Send private message Send e-mail Visit poster's website
adam2
Site Admin


Joined: 02 Jul 2007
Posts: 6220
Location: North Somerset

PostPosted: Sat Nov 26, 2016 5:40 pm    Post subject: Reply with quote

I don't have means of measuring the light output but to the naked eye it looks unchanged over the range of 10 volts to 30 volts.

Below 10 volts they dim noticeably, and go out entirely below about 8 volts.

The light output of a single lamp is fine for standby lighting of a reasonable size room but rather meagre as the only or main lighting for a living room.

It should be noted that this style of lamp is new to the market and that future batches from the same supplier may have different specifications.
_________________
"Installers and owners of emergency diesels must assume that they will have to run for a week or more"
Back to top
View user's profile Send private message
Mr. Fox



Joined: 24 Nov 2005
Posts: 491
Location: In the Dark

PostPosted: Sun Nov 27, 2016 1:52 pm    Post subject: Reply with quote

We tend to use multiple downlights in I<eetshin and Bathrooms as they help to avoid shadows on work areas/sinks (compared to single central area lights).

A nice solution for ambient area lighting I've used before is to have the LED tape (3528 warm) stuck along the tops of picture rail, facing upwards (so the light bounces off the ceiling). Also perfect for 'under cupboard' use in I<eetshins.

Another nice package I've used is the little 4.8W COB strip - again, best to bounce it off a white surface, as they're ridiculously bright (ideal for uplighters, etc).

With all 12v LED lighting, I've always found it beneficial to use some sort of driver (rather than running off straight 12v DC). This not only gives you 'dimming' ability, but saves a lot of power (for no discernible loss of light output) due to the non-constant current.

The cheap 2A per channel 24 key 3-channel RGB controllers work fine, plus you get a remote control! Very Happy
Back to top
View user's profile Send private message
woodburner



Joined: 06 Apr 2009
Posts: 3384

PostPosted: Sun Nov 27, 2016 9:14 pm    Post subject: Reply with quote

Those controllers seem a tad complex.
_________________
If you think the economy is more important than the environment, try holding your breath while you count your money.
Back to top
View user's profile Send private message
adam2
Site Admin


Joined: 02 Jul 2007
Posts: 6220
Location: North Somerset

PostPosted: Sun Nov 27, 2016 10:31 pm    Post subject: Reply with quote

woodburner wrote:
Those controllers seem a tad complex.


Yes, but they can be useful if you want various added features such as controlling the colour of multi colour LED lighting tape, or cordless remote control.

No such controller is needed for the 12 volt LED light bulbs to which I linked, these simply need inserting into a lampholder wired onto a 12 volt, 16 volt, or 24 volt circuit. Just like inserting a 240 volt lamp into a lampholder on a 240 volt circuit.
_________________
"Installers and owners of emergency diesels must assume that they will have to run for a week or more"
Back to top
View user's profile Send private message
Mr. Fox



Joined: 24 Nov 2005
Posts: 491
Location: In the Dark

PostPosted: Mon Nov 28, 2016 11:47 am    Post subject: Reply with quote

The controllers I've used 'remember' their settings when powered off, so you can just use them to set the levels and then just use power switch to turn them on and off in the usual way, putting the remote control away in a drawer.

Setting them to 'full' still saves energy over running off direct 12vdc, with no apparent decrease in brightness.

You can use these RGB controllers to run three separate channels (strips) of warm white, not just the coloured strips.

I must admit that I'm a little concerned that you appear to be able to get 12vdc LED lamps that fit into standard E14/E27 fittings... there's a potential for disaster from inadvertently placing onto a 230vac supply. Shocked
Back to top
View user's profile Send private message
clv101
Site Admin


Joined: 24 Nov 2005
Posts: 7636

PostPosted: Mon Nov 28, 2016 12:14 pm    Post subject: Reply with quote

Mr. Fox wrote:
A nice solution for ambient area lighting I've used before is to have the LED tape (3528 warm) stuck along the tops of picture rail, facing upwards (so the light bounces off the ceiling). Also perfect for 'under cupboard' use in I<eetshins.


This is what I meant about the rebound effect. I've got some of these strips and while they can be make a great effect they are a very inefficient way of lighting a space!

As adam2 points out, the 'filament' style bulbs are now available in 12V versions. I think these, together with some targeted work area lighting might be the ideal domestic solution.
_________________
PowerSwitch on Facebook | The Oil Drum | Twitter | Blog
Back to top
View user's profile Send private message Visit poster's website
Mr. Fox



Joined: 24 Nov 2005
Posts: 491
Location: In the Dark

PostPosted: Tue Nov 29, 2016 12:56 am    Post subject: Reply with quote

Personal preference, I guess. Smile Many people don't much like the 'glare' from single high output sources - hence lampshades.

We have the filament type (6W 240vac) as main room lights and a variety of smaller task lights (e.g. these) dotted around. The main light only ever gets switched on when I can't find something. Very Happy

In my last place I had the strips ('rebound') along the picture rails and found them fine for general use - that was all 100% 12vdc with automatic battery backup (I was on a prepaid meter).

The new place I rewired from scratch, but didn't bother with the 12vdc system (no room for picture rails, for a start). I'll probably come to regret it one day, but only for as long as the battery would have held out. Wink
Back to top
View user's profile Send private message
Pepperman



Joined: 10 Oct 2010
Posts: 759

PostPosted: Wed Nov 30, 2016 9:02 am    Post subject: Reply with quote

What do you mean by filament? I understand those to be the retro, low output lamps favoured by coffee shops in Hackney. You can get very good quality LED replacements for those but they give a (deliberately) very low light output.

Do you mean conventional GLS style lamps? I have seen 12V GLS style LED lamps on sale but not seen anything with a decent colour rendering index.
Back to top
View user's profile Send private message
adam2
Site Admin


Joined: 02 Jul 2007
Posts: 6220
Location: North Somerset

PostPosted: Wed Nov 30, 2016 10:09 am    Post subject: Reply with quote

The lamps in question make use of LEDs in long very thin strips that are arranged so as to somewhat resemble the filament of an old fashioned lamp.

These have been sold in 240 volts for a couple of years, but the 12 volt ones are much more recent.

The decorative 240 volt lamps come in various designer or trendy shaped bulbs.

The 12 volt ones come in GLS, golfball, and candle shapes, and possibly others.

I have tried some 6 watt lamps, regrettably from a tax avoiding on line retailer, and also some 4 watt lamps from a German fleabay seller.

Both claim to produce 100 lumens per watt, which may be a bit exaggerated, but was still subjectively impressive for the wattage consumed.

The 4 watt/400 claimed lumens lamps are similar in output to a 40 watt mains voltage incandescent lamp. Ample for emergency or standby lighting of a large room, but a bit meagre for the main or normal lighting, unless multiple lamps are used.

The 6 watt lamps are brighter but had a slight flicker.
_________________
"Installers and owners of emergency diesels must assume that they will have to run for a week or more"
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic    PowerSwitch Forum Index -> Electrical, Theory and Practice All times are GMT + 1 Hour
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum


Powered by phpBB © 2001, 2005 phpBB Group