breff Posted September 24, 2013 Share Posted September 24, 2013 I'm fed up of the kids leaving the bathroom and kitchen downlighters on all night wasting electric and costing me money, so I saw some 12v Led MR11 bulbs in the CPC catalog and thought I'd give them a try. The existing downlighters in each room are 4x20w halogens already 12v. I started replacxing the bulbs 1 at a time and all seemed good until I removed the last halogen when all the LEDs went dim. I have seen that there are LED Driver Transformers but what is the difference to a normal transformer and why did the LED bulbs work while there was 1 Halogen connected?? The opinions I express are mine and are usually correct! (Except when I'm wrong)(which I'm not) Link to comment Share on other sites More sharing options...
datadiffusion Posted September 24, 2013 Share Posted September 24, 2013 Suspect you have an electronic transformer and it sees the new LED bulbs as 'no load' and is throttling its output. Also I'm assuming the lamps do have built in regulators (most, but not all 'replacement' types do). With one incandescent lamp left it was still providing the output. Most (but not all) other 'pure' LED lamps require a constant current or constant voltage source, like the 1W readings ones we've got on our bed. Replacement styles don't usually. However most existing 'low voltage' lamps are simpy 12VAC as I'm sure you know. This might solve your problem; http://www.tlc-direct.co.uk/Products/TLT50slash1.html Or whatever driver they recommend for the lamp. Whats the P/N for your lamps? p.s its the way to go, we used to have 6 x 50W in our kitchen, now 6 x 5W LED supplemented with some LED strips under the cabinets = its da bomb! So, I've decided to take my work back underground.... to stop it falling into the wrong hands Link to comment Share on other sites More sharing options...
goncall Posted September 24, 2013 Share Posted September 24, 2013 Suspect you have an electronic transformer and it sees the new LED bulbs as 'no load' and is throttling its output. Also I'm assuming the lamps do have built in regulators (most, but not all 'replacement' types do). With one incandescent lamp left it was still providing the output. Most (but not all) other 'pure' LED lamps require a constant current or constant voltage source, like the 1W readings ones we've got on our bed. Replacement styles don't usually. However most existing 'low voltage' lamps are simpy 12VAC as I'm sure you know. This might solve your problem; http://www.tlc-direct.co.uk/Products/TLT50slash1.html Or whatever driver they recommend for the lamp. Whats the P/N for your lamps? p.s its the way to go, we used to have 6 x 50W in our kitchen, now 6 x 5W LED supplemented with some LED strips under the cabinets = its da bomb! as data says,some t/f need a minimum load hence the last halo you took out,agree on the led strips,kids have them on day and all night for background lighting cost nowt to run Link to comment Share on other sites More sharing options...
sixwheeledbeast Posted September 24, 2013 Share Posted September 24, 2013 Are the lamps series or parallel? It's to do with the load as above. The resistive load of the one bulb is keeping the voltage/current at the correct value for the LED lamps. If you don't have the correct transformer constant current or constant voltage, it will only damage the LED's quicker; due to the higher forward voltage on the diode. Link to comment Share on other sites More sharing options...
breff Posted September 24, 2013 Author Share Posted September 24, 2013 They are all in parallel, anyway of lashing something like adding a resistor in parallel or will it have to be such a high wattage resistor that I wont be saving any energy The opinions I express are mine and are usually correct! (Except when I'm wrong)(which I'm not) Link to comment Share on other sites More sharing options...
datadiffusion Posted September 24, 2013 Share Posted September 24, 2013 Are the lamps series or parallel? It's to do with the load as above. The resistive load of the one bulb is keeping the voltage/current at the correct value for the LED lamps. If you don't have the correct transformer constant current or constant voltage, it will only damage the LED's quicker; due to the higher forward voltage on the diode. Not if they are replacement types - they have built in ballast. But still not enough load for the transformer... They are all in parallel, anyway of lashing something like adding a resistor in parallel or will it have to be such a high wattage resistor that I wont be saving any energy Don't do that, if they are replacement types they have built in ballast/rectifier. You only need to change the trafo for a normal non electronic type, but if you let me know the CPC part number I can have a look? So, I've decided to take my work back underground.... to stop it falling into the wrong hands Link to comment Share on other sites More sharing options...
breff Posted September 24, 2013 Author Share Posted September 24, 2013 LP0463805 The opinions I express are mine and are usually correct! (Except when I'm wrong)(which I'm not) Link to comment Share on other sites More sharing options...
MrHappy Posted September 24, 2013 Share Posted September 24, 2013 not fancy an occupancy switch ? Mr Veritas God Link to comment Share on other sites More sharing options...
datadiffusion Posted September 24, 2013 Share Posted September 24, 2013 Ah, I take it all back. A LOT of these repalcement types have built in rectifier to work off AC/DC. All the ones on my narrowboat do cos of spackers hiring it that put them into DC sockets the wrong way for a start... But this one is def DC... Voltage: 12V DC 40 Lumens Average life time: 30,000 - 50,000 hours Available in daylight white or warm white Please note: Must be used with a led driver transformer e.g. LP02591 So, I've decided to take my work back underground.... to stop it falling into the wrong hands Link to comment Share on other sites More sharing options...
MrHappy Posted September 24, 2013 Share Posted September 24, 2013 All the ones on my narrowboat BTW I'm thinking snorkel & a cordless drill... Mr Veritas God Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.