robdav Posted October 8, 2018 Share Posted October 8, 2018 Hi I've read a lot of threads on this forum about LED lights and dimmers. We have some in our van that are too bright and I would like to know if we can install a dimmer or not? I will attach a photo of the back of one of the LED lights. This is what the label has printed on the back but how on earth do you find out if they are dimmable and if they are, what dimmer to use? 200 SMB1-18CRD, DC9-14V AC9-12V Max: 1,5W 18SMD Any advice appreciated. Thanks Rob Link to comment Share on other sites More sharing options...
hallii Posted October 8, 2018 Share Posted October 8, 2018 Dimming as in using a dimmer switch will blow the leds unless they are marked "dimmable". The one in your photo can be dimmed by simply adding a series resistor thus dropping the voltage a bit. To do it properly you need to use ohms law and do some simple sums, or just select a low value resistor by trial and error. H Link to comment Share on other sites More sharing options...
plwsm2000 Posted October 8, 2018 Share Posted October 8, 2018 Most LED modules powered from12VDC will be dimmable unless they contain any other electronics apart from the actual Light Emitting Diodes and current limiting resistors. (The same thing cannot be said for 240VAC LEDs as these always have some built in electronics to drop the main voltage down to a few volts for the LE Diodes). I have come across one or two modules that have some extra electronics to give a constant current draw. These have a constant brightness even when the 12V is nearer 14.5V during battery charging. Some modules also have extra electronics to give a "touch on/off" function. I doubt if either of these types will be dimmable. If your LED module doesn't have these features (i.e it doesn't switch on & off when you touch it, or it gets noticably brighter when you are on EHU), you can probably dim it with a high power resistor to drop a couple of volts or use a dimmer unit suitable for 12V DC. (Note the resistor will get quite warm as it will be dissipating some power). These types of dimmers work by switching the LEDS on and off many times a second. The ratio of "on" to "off" time affects how bright they are.The human eye doesn't respond fast enough to see the switching, but if you look at them through a digital camera you should see them flicker. Most cheap dimmers tend to switch the 0V rather than the 12V feed. These work well in most situations but won't work if the LED lights have been wired directly to 0V rather via a common 0V wire back to the dimmer. Link to comment Share on other sites More sharing options...
Derek Uzzell Posted October 8, 2018 Share Posted October 8, 2018 I’m guessing that the lights are made by the Chinese company Dimatec Spa (example in attached photo) and some of these are advertised as having ‘touch’ On/Off switching. Assuming that the lights are original rather than retro-fitted, it might be useful to know what make/model/age of (French) motorhome Rob owns. Link to comment Share on other sites More sharing options...
robdav Posted October 8, 2018 Author Share Posted October 8, 2018 Thanks for the replies so far. Any recommendations on a suitable dimmer would be helpful. I'm not an electrician but can cope with most things. It's a Pilote panel van conversion 2018 model. The LEDs came fitted a standard but are very bright. They have a simple mechanical on off switch, not a touch switch as such. Link to comment Share on other sites More sharing options...
Derek Uzzell Posted October 9, 2018 Share Posted October 9, 2018 The standard specification of some recent Pilote motorhomes includes a dimmer switch for the indirect lighting, so a Pilote dealership might be able to tell you the make/model of switch Pilote employs and/or whether the LED lights on your vehicle are suitable for dimming. This March 2018 discussion related to adjusting the brightness of an awning LED strip https://forums.outandaboutlive.co.uk/forums/Motorhomes/Motorhome-Matters/Fitting-a-dimmer-switch-Query-/48893/ but there seems to be an element of suck-it-and-see regarding which switches will work with which LED lights. Link to comment Share on other sites More sharing options...
747 Posted October 9, 2018 Share Posted October 9, 2018 I bought some variable resistors from China to reduce the voltage to some COB LEDs that were melting my light fittings. I reduced the voltage and it reduces the brightness somewhat also. A bag of 5 cost very little. Link to comment Share on other sites More sharing options...
Charles Posted October 10, 2018 Share Posted October 10, 2018 747 - 2018-10-09 12:56 PM I bought some variable resistors from China to reduce the voltage to some COB LEDs that were melting my light fittings. I reduced the voltage and it reduces the brightness somewhat also. A bag of 5 cost very little. I'm surprised variable resistors can handle the power dissipation, perhaps they're big ones? Ideally you need a buck converter type of circuit. I bought one of the controllers below but it was DOA from China. Still, it gets good reviews. https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.co.uk%2Fulk%2Fitm%2F222966511010 I ended up building my own pwm circuit that works very well. Link to comment Share on other sites More sharing options...
Derek Uzzell Posted October 10, 2018 Share Posted October 10, 2018 It would be interesting to know how much the Dimatec light could be bought for in the UK, as this Italian advert quotes a price of €7.11 https://www.camperonsale.it/index.asp?divleft=accessori&divcenter=accscheda&id=ACC1262&divbottom=vuoto At that sort of expenditure, before altering the present electrical system of Rob’s Pilote motorhome, he could experiment separately and, if the light would not dim properly or became damaged, it would not break the bank. (I bet Pilote’s parts-list has a mite higher price for a replacement light...) Link to comment Share on other sites More sharing options...
robdav Posted October 10, 2018 Author Share Posted October 10, 2018 If I'm honest it would be great if the van builders who are installing LED lights by default could include a dimmer. I think I'll try covering one of the lights with a transparent coloured piece of material (making sure it doesn't get too hot) and see how it goes. Thanks for the replies. Link to comment Share on other sites More sharing options...
Derek Uzzell Posted October 10, 2018 Share Posted October 10, 2018 There’s a long ‘technical’ discussion here https://www.caravantalk.co.uk/community/topic/124432-led-light-dimmer/ (Best of luck!) Link to comment Share on other sites More sharing options...
plwsm2000 Posted October 10, 2018 Share Posted October 10, 2018 robdav - 2018-10-10 3:34 PM If I'm honest it would be great if the van builders who are installing LED lights by default could include a dimmer. I think I'll try covering one of the lights with a transparent coloured piece of material (making sure it doesn't get too hot) and see how it goes. Thanks for the replies. Some manufactures do include dimmers but they just add to the cost. My van uses a Schaudt LIS101 dimmer unit and CBE/Berker push button to control my spotlights. I know an extra £50 or so (plus labour) on top of something costing 10's of thousands doesn't seem alot, but I guess every penny counts these days. The parts that are contained in the thread in Derek's link do work for these LEDs and they should significantly reduce the power consumption of your lighting. My van also has lots of strip lighting that initially did not have a dimmer. These took nearly 4 Amps and were too bright. I fitted the same item as Charles linked to (above). My only problem with it is that it switches the 0V line so all lights need to have a common 0V rather than being connected locally to chassis 0V. Once I sorted this out, the striplight drops from 4A to less than 1A when dimmed to "mood" lighting. Link to comment Share on other sites More sharing options...
robdav Posted October 10, 2018 Author Share Posted October 10, 2018 plwsm2000 - 2018-10-10 4:23 PM robdav - 2018-10-10 3:34 PM If I'm honest it would be great if the van builders who are installing LED lights by default could include a dimmer. I think I'll try covering one of the lights with a transparent coloured piece of material (making sure it doesn't get too hot) and see how it goes. Thanks for the replies. Some manufactures do include dimmers but they just add to the cost. My van uses a Schaudt LIS101 dimmer unit and CBE/Berker push button to control my spotlights. I know an extra £50 or so (plus labour) on top of something costing 10's of thousands doesn't seem alot, but I guess every penny counts these days. The parts that are contained in the thread in Derek's link do work for these LEDs and they should significantly reduce the power consumption of your lighting. My van also has lots of strip lighting that initially did not have a dimmer. These took nearly 4 Amps and were too bright. I fitted the same item as Charles linked to (above). My only problem with it is that it switches the 0V line so all lights need to have a common 0V rather than being connected locally to chassis 0V. Once I sorted this out, the striplight drops from 4A to less than 1A when dimmed to "mood" lighting. Whereabouts in Somerset are you? I'm near Cheddar, perhaps I can come and have a chat? Link to comment Share on other sites More sharing options...
747 Posted October 10, 2018 Share Posted October 10, 2018 Charles - 2018-10-10 12:28 AM 747 - 2018-10-09 12:56 PM I bought some variable resistors from China to reduce the voltage to some COB LEDs that were melting my light fittings. I reduced the voltage and it reduces the brightness somewhat also. A bag of 5 cost very little. I'm surprised variable resistors can handle the power dissipation, perhaps they're big ones? Ideally you need a buck converter type of circuit. I bought one of the controllers below but it was DOA from China. Still, it gets good reviews. https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.co.uk%2Fulk%2Fitm%2F222966511010 I ended up building my own pwm circuit that works very well. The ones I bought are shown on this thread. https://forums.outandaboutlive.co.uk/forums/Motorhomes/Motorhome-Matters/21w-Flourescent-modified-to-2w-LED-1-50-How-to/45945/ I fitted one per COB LED in my fluorescent fittings. They are the ones shown at the start of the thread. It was a simple soldering job. Link to comment Share on other sites More sharing options...
plwsm2000 Posted October 10, 2018 Share Posted October 10, 2018 robdav - 2018-10-10 4:34 PM Whereabouts in Somerset are you? I'm near Cheddar, perhaps I can come and have a chat? Sure. Just sent you a PM with my contact details. Phil P.S. The PM I sent is still in my outbox. Have you set up your account properly as I can send to others ok? Link to comment Share on other sites More sharing options...
robdav Posted October 10, 2018 Author Share Posted October 10, 2018 plwsm2000 - 2018-10-10 5:04 PM robdav - 2018-10-10 4:34 PM Whereabouts in Somerset are you? I'm near Cheddar, perhaps I can come and have a chat? Sure. Just sent you a PM with my contact details. Phil P.S. The PM I sent is still in my outbox. Have you set up your account properly as I can send to others ok? Hi Phil, have replied to you PM but mine also still sitting in my Outbox but assuming you'll get mine if I got yours. Thanks. Link to comment Share on other sites More sharing options...
Derek Uzzell Posted October 10, 2018 Share Posted October 10, 2018 A PM will stay in the sender’s Outbox until the recipient it’s being sent to opens the message. When that happens the PM should move from the sender’s Outbox to the sender’s “Sent Items” box. Link to comment Share on other sites More sharing options...
robdav Posted January 15, 2019 Author Share Posted January 15, 2019 robdav - 2018-10-08 1:35 PM Hi I've read a lot of threads on this forum about LED lights and dimmers. We have some in our van that are too bright and I would like to know if we can install a dimmer or not? I will attach a photo of the back of one of the LED lights. This is what the label has printed on the back but how on earth do you find out if they are dimmable and if they are, what dimmer to use? 200 SMB1-18CRD, DC9-14V AC9-12V Max: 1,5W 18SMD Any advice appreciated. Thanks Rob In case anyone is interested, I ended up fitting a couple of these and they work great. You need to leave the main switch on all the time as they can only be switched on and off via touch control on the rim but they are much softer than the factory fitted lights and can be dimmed and controlled independently. https://www.atenlighting.co.uk/led-recess-touchdim.html Link to comment Share on other sites More sharing options...
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