Fitting a dimmer switch - Query.

[Berniea]

Have fitted Thule LED strip ( ribbon type) to our awning and it look fantastic apart from the fact that they are very bright. I have to drop out a couple of feet of awning to dim the light a bit!

So, I thought it make sense to fit a dimmer switch. The van currently has a rocker switch fitted and I think this might be important.

I bought a Berker switch that I know works on other vans with the same arrangement.

The rocker switch has two wires going into it and when I remove the wires from the switch I can simulate what the rocker switch does by touching the two wires together. When they touch the light comes, on and will stay on even when the two wires are not touching, when I touch them together again, the light goes off and stays off.

When I wire the dimmer according to the instructions ( I'll post a pic when Im able of simple wiring diagram) it just doesnt work at all ...... nothing!

I'm thinking the switch might be damaged and to test it I tried a continuity test - I'm not getting anything through the switch which suggests the dimmer might not be working at all. Should I be abel to test a dimmer using a continuity test or is this not possible with this type of switch?

Any help would be appreciated.

 

[Grumblewagon]

Not all LEDs are dimmable. Check if your ones are.

[Derek Uzzell]

I agree.

 

There’s nothing in the documentation for the Thule LED strip

 

https://www.thule.com/en-gb/gb/motorhome-accessories/awning-accessories/thule-led-strip-_-307134

 

that suggests that it can be dimmed or states that it cannot, but the chances are that the product is not dimmable.

 

Check with Thule or the supplier.

 

 

[plwsm2000]

Most 12V LED strip lights are just a bunch of LEDs with current limiting resistors. If this is the case with the Thule strip lights, then they will be dimmable.

It is not clear if you have a standard on/off rocker switch and a separate dimmer module or a complete dimmer unit all in one. If you have a standard rocker switch, then you should be able to test it with a continuity tester. If it is an integrated unit, a standard continuity tester will not work (and you may get different results just be swapping the polarity of the meter leads).

Note that most 12V LEDs are DC (polarized) so make sure you connect + & - the correct way round.

 

[Grumblewagon]

While the LED itself is polarised, most light fittings are not. For a simple indicator light, and LED and a resistor is fine but for illumination, the LEDs are generally driven by electronics which regulate the current through the LED. Using a resistor would be very wasteful and generate a lot of heat. I replaced the halogen bulbs in my van with LEDs which are not polarised.

[ColinM50]

cut and pasted from Google;

The complex circuitry in these new bulbs makes them difficult to dim. In many cases, a typical dimmer switch (now called a legacy dimmer in the electrical industry) won't work properly, if at all, with CFL or LED bulbs.

 

Legacy dimmers were designed to work with incandescents, and CFL and LED bulbs bear no electrical resemblance to these types of bulbs. Comparing them is like equating an electric heating element and a television set. Both use electricity and both give off light, but that's where the similarity ends.

 

The solution is to buy a dimmer switch rated for both CFL and LED bulbs. Two reputable manufacturers of CFL/LED dimmers are Leviton and Lutron; both provide lists of bulbs they've verified will work with their dimmers. Next, buy dimmable CFL and LED bulbs that you know will function with your switch. Though these bulbs may also work with the older legacy dimmers, it's likely you'll experience some of the problems you mentioned. It's worth noting that in 2011 the National Electrical Code was changed specifically to require a neutral wire at all switch locations. But don't worry you can install most new switches in an older house so long as you carefully follow the manufacturer's instructions. If you have any questions about whether a specific switch is compatible with your wiring or a specific bulb or light fixture, contact the manufacturer's technical service department.

[plwsm2000]

I think people may be confusing domestic 230V AC LED units with 12V (DC) strip lights.

The 230VAC units wil have some built in electronics to rectifiy the AC and drop it down to the 2-3V needed for the actual light emitting diode (while the actual LED is inherently dimmable, the electronics that drive it may not be). The 12V strip lights are usually made up of 3 LEDs connected in series with a small resistor to limit the current. This sequence is repeated along the entire strip every 3cm or so (about 60 LEDs per meter) all connected in parallel. I agree that the resistors wastes power, but it is relatively small.

There is no information about the Thule strip light, but looking at the photo, you can see the 3 LED + resistor arrangement I mentioned above. This type of strip light IS dimmable and IS polarized. I have LED strip lights in my van and also have similar LED lights at home with 12V DC dimmers.

 

[747]

I fitted COB LED lights but they ran very hot. I fitted 12 volt regukators bought from China before each one and it not only solved the problem, it made the brightness adjustable. They only cost pennies and once you are happy with the brightness, you will not need a dimmer switch.

[Keithl]

Berniea - 2018-03-08 9:59 PM

 

The rocker switch has two wires going into it and when I remove the wires from the switch I can simulate what the rocker switch does by touching the two wires together. When they touch the light comes, on and will stay on even when the two wires are not touching, when I touch them together again, the light goes off and stays off.

 

 

Bernie,

 

Unfortunately you will not be able to replace your switch with a dimmer as it is not an On/Off switch.

 

From the above comment about touching the wires once to turn on, and again to turn off, your switch must be a 'Momentary' click and release type.

 

There will then have to a 'Latching relay' style of unit somewhere between the switch and light. If you could locate and remove this unit you might be able to wire in your dimmer.

 

Keith.

[Derek Uzzell]

Aten Lighting markets dimmer devices

 

https://www.atenlighting.co.uk/caravan-motorhome-lighting/flexible-led-strip-lighting/accessories

 

but they are generally advised as being "Only suitable for use with our range of flexible LED strip."

[Berniea]

Been away a couple of day hence no response from me.

 

When the two wires are touched together I can indeed hear a click from somewhere (hidden), which suggests that there is a relay in the circuitry.

That said, I've done a bit more research and it appears that the dimmer switch I've bought is not suitable for LED's! (£70 down the pan!). Berker do make a switch that is designed for dimming LED's and I reckon this will have to be my next purchase.

I take on board the comment regarding Thule not stating if they are dimmable but I do know that at least one manufacturer that fit these lights at the factory - I really want to come up with a solution to this so may ask their technical dept for advice.

 

 

 

[Charles]

After seeing all the cheap rubbish on ebay I made a dimmer circuit for my 12v LED downlighters. It's an efficient PWM type with 555 chip and power transistor. Works very well. I know it's not for everyone mind. Circuit available upon request :-)

[Derek Uzzell]

This German advert

 

https://www.frankana.de/en/thule-omnistor-led-lichtstreifen-59951.html#v_89_797

 

says "Using a suitable dimmer (Item no. 321/277) the brightness can be adjusted”.

 

Item no. 321/277 refers to this Berker product

 

https://www.frankana.de/en/integro-touch-slide-led-dimmer-74601.html#v_321_277

[Deneb]

I have two of these fitted in my van by Vantage for the overhead LED strip lights.

 

http://www.rainbow-conversions.co.uk/cbe-motorhome-caravan/electronic-dimmer-12v-3a-753-p.html

[Berniea]

Thanks for this link - This switch does appear to be suitable (indeed it must be because you have two fitted already), the only issue I can see with this is

1. The colour. (it might look a bit odd alongside two other chrome switches)

2. I would need to make modifcations to the current wirning because I dont have a load, earth and 12v supply.

[Berniea]

Sorry to keep banging on with this but Im a man on a mission!! :-D

 

I contacted the manufacturer and they have advised me that the LED’s are indeed dimmable( as several people on here have already stated) and when they fit these lights, they incorporate a remote control dimmer into the circuit, which I can buy for a mere £160.00!

 

If an LED strip is made up in the same way as the Thule LED ribbon, and I believe they all are, couldn’t I use a cheap eBay remote control kit (and discard the LED ribbon), for a fraction of the cost?

 

I'm thinking I would leave the existing rocker switch in place, and switch the lights on and off at this rocker switch, only using the remote control dimmer to do just that .........dim and brighten the lights.

 

Is this too simplistic?

[Berniea]

Would this work?

https://www.amazon.co.uk/niceeshop-Controller-Dimmer-Wireless-Control/dp/B00GUBNDI4/ref=pd_cp_147_3?_encoding=UTF8&psc=1&refRID=YEQX4AWW47EXAWCP83AT

 

Using the principle that I leave the rocker switch in place and incoporate this simple unit into the led feed?

[Charles]

Yes it would work in theory, the rocker switch would in effect be an isolator so there's no small current drain when they're off.

 

BUT I bought one of those dimmers and it didn't work, did absolutely nothing. I suppose some will be alright but how long will it last? The components will probably all be underrated and get hot.

 

You can buy multy colour strips that come complete with a remote, maybe a better way to go although I don't know if they dim from the remote.

[Charles]

These German ones look good

 

https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.de%2Fulk%2Fitm%2F272286216316

 

They've got dimming buttons on the (radio frequency) remote and there are 60 LEDs per metre rather than the cheap Chinese ones with just 30. There's also a nice wall controller available.

[Derek Uzzell]

The following link has a good deal of advice on methods of dimming LED ’tape’

 

https://www.instyleled.co.uk/support/how-do-i-dim-led-tape/

 

This is the dimmer marketed by Aten Lighting for £8.99

 

http://www.farnell.com/datasheets/2058688.pdf

 

The specification suggests that a voltage regulator (Aten Lighting price £11.49) might also be needed.

 

Aten Lighting also advertise an in-line LED dimmer for £4.99

 

https://www.atenlighting.co.uk/led-dimmer-inline.html

 

My experience of dealing with Aten Lighting is that they are well clued-up and - as their advice will be free - it would be worth asking their opinion before spending money on devices that might or might not work with the Thule strip.

[plwsm2000]

Berniea, the dimmer that you linked to should work ok but you should check what it does when first switched on. Does it go to full on, full off, some random level or (hopefully) its last setting? Since you are going to remove power from it using your rocker switch, it may not "remember" its last setting. I guess you don't want to keep resetting the dimming level every time you switch on the awning light?

The manual dimmer that Derek linked to may be a safer option as the manual control means it always will come on in the same position.

I have used these Wireless-Dimmer-Remote-Control-Dimmable before in my house and they do remember their last setting. The only problem I would have is that the connectors are the spring type contacts that you often get with loudspeakers and I am not sure if they will withstand the shock and vibrations in a motorhome.

 

Having a separate inline switch to the dimmer is a good option as these dimmers usually take around 6mA even when the output is off. If power is applied 24/7, the drain on your battery starts to add up.

 

One other point - the Thule strip has a current of 340-380mA per meter (about 1.5A for a 4m length) but this is at 12V. Unless your battery is completely flat, the supply voltage will be a fair bit higher. Depending on your battery and charger types and where it is in its charging state, you could see voltages close to 15V. Although this is only a 25% increase in voltage, the current in these LED strips will almost DOUBLE at 15V and they will get even brighter (but not twice as bright). Under these conditions, the life of the LEDs will be drastically reduced. For this reason alone, I would always use a dimmer or reduce the supply voltage somehow.

 

[Berniea]

Thnks all for the great advice.

in addition to the dimmer I previoulsy linked Ive also bought this one:

 

https://www.amazon.co.uk/Dimmer-Brightness-Control-Controller-12V-24V/dp/B01081JRDQ/ref=sr_1_22?ie=UTF8&qid=1520956595&sr=8-22&keywords=12v+led+dimmer+switch

 

I should receive it tomorow - so I'll soon see if it works.

 

plwsm2000 - I tried to buy the dimmer you suggested but when I looked yesterday evening the suppliers I tried couldnt deliver for several weeks - I'm impatient!

I didnt relaise that dimmers will draw a cuurent so the rocker switch in the circuit is actually a bit of a bonus.

Once dimmed, the redcution of voltage should ancourage an extended life on the Thule (expensive) lights.

 

 

 

 

[Derek Uzzell]

This device is widely advertised on-line at a price as low as just over a quid and, consequently, there are lots of reviews commenting on performace and build-quality.

 

I happened to be talking to Aten Lighting (who offer this dimmer) and gained the impression that it uses pulse-width modulation. So you might notice flickering when your led strip is dimmed. Given the price, it’s a risk worth taking.

[Berniea]

Just to conclude ...... fitted this dimmer today and it works great.

 

https://www.amazon.co.uk/dp/B01EJ75Q3U/ref=cfb_at_prodpg

 

The fact that it uses radio frequency is a bonus because the dimmer unit is hidden behind a panel and can't be seen. The dimming is linear and from bright to it's dimest and vice vera and when switched on and off at the rocker switch it "remembers" the last setting.

Thanks All.