Converting lamps to 12/24V?

[Andras]

Hi have quite a few desk lamps, mostly from IKEA employing an E14 socket with 230V LEDs in them. These lamps are plugged into wall sockets that are wired directly to my wiring closet where they are currently hooked up to KNX relays.

It always annoyed me that I am only able to on/off control them and not dim them (yeah, I know...). My idea was to convert the lamps by:

1) switching the bulb to a E14 12/24V LED bulb - no hacking of the lamp body required

2) changing the wall sockets and lamp plugs (eg to UK sockets and plugs - I'm in the other part of Europe) to make sure no one plugs this converted lamp to a 230V socket and no 230V accessories are connected to the converted sockets

3) rewiring the other end of the cable and driving it using a 12/24V dimmer instead of a 230V relay

I immediately got stuck on point 1, didn't find a bulb that would be warm white, E14 and dimmable. Any pointers?

Any thoughts regarding the concept?

[David Wallis]

fwiw - in the uk we use the old style plugs for lighting circuits:

https://www.screwfix.com/p/5a-round-pin-plug-white/22877

edit to add but they are typically mains voltage!

[Techdoctor]

Why not just remove the E14 socket completely and use an LED strip inside the shade. 

[Andras]

Starting to feel that's the most reasonable solution, yeah. Was originally looking for something with an opal bulb to spread the light evenly.

[Duncan]

replace the knx relays in your cabinet with knx dimmers, and swap the sockets to the 5A round pin types illustrated by David - you then have the whole market of dimmable E14 led bulbs to choose from for K, colour rendering, brightness etc

[Andras]

Update on my progress:

For the larger standing lamps, I took your advice and simply wrapped a 24V LED strip around the base of the lamp. Had to make sure some part of the strip is angled towards the top to replicate the upward shining bulbs. Works great. Thanks for the idea.

As for the smaller desk lamps, I took apart an IKEA Solbo "owl" lamp and had a look inside. Turns out it's a 24VDC lamp inside with a GUZ5.3 socket using an external power supply. Now I just need to test how the bulb behaves when dimming through PWM. If dimming works, I'll just buy a couple of these owl lamps for 15€ each and replace socket and bulb with these in the other ordinary desk lamps.

@Duncan, I thought about doing 230V dimming as well, but as I have a lot of spare low voltage dimming channels, I wouldn't want to invest in new gear in the wiring closet.

On Monday, September 9, 2019 at 2:23:24 PM UTC+2, Techdoctor wrote:

[Andras]

The IKEA Solbo lamp with the GUZ5.3 24VDC bulb in it works wonderfully with the Loxone dimmer. Dims nicely, without any sound, whine or buzz, even down to 1%.

Off to IKEA to buy a few more of these :)

[Andras]

Reporting back on this thread.

Meanwhile, I got a few more of these lamps and converted most of my 230V desk lamps. The Solbo lamp has a rather small circular socket that fits quite well with some glue into the regular E14 socket. Wiring was also quite straightforward. Freed up quite a few relay outputs as well.

Now all my lamps in my living space are dimmable and dim up and dim down in sync. Happy now :) 

[David Wallis]

Any chance of a couple of pics of what you have done?

[Andras]

Sure.

These were the original lamps, 230V with E14 sockets.

This is how the "donor" lamp (IKEA Slobo "owl" lamp) looks like in the inside.

The socket is a GUZ5.3 which is a polarity protected GU5.3. The inside round socket can be easily removed from the snap-lock, so you'll get a socket that's around 2cm in diameter.  

The GUZ5.3 socket fits neatly in the original E14 socket with the wires pushed through the holes and soldered to the original lead. I have used a fair bit of hot glue to keep things stable:

I have used the original lamp lead and have replaced the connector with a fused UK plug (our native plugs are type F), so it's not possible to mistakenly connect this lamp to 230V. I have used the two main contacts (neutral and live) but thinking about it more closely, it would have made better sense to use the neutral and ground connectors for this type of hacked usage.

Of course, I have also replaced the socket with a UK socket, put some 24V stickers on it and changed the wiring in the wiring closet so this outlet is not controlled by a 230V KNX relay but a Loxone 24V RGBW Tree dimmer. The light dims nicely without flickering, down to about 8%.

It took about 1.5-2 hours to convert two of these lamps, but most of the time was spent on figuring out a good way to place the socket and glue it.