# 12v LEDs DC or AC



## Whiskeymac (Jul 20, 2005)

In links from a club article on replacing 12v conventional lights to LEDs,
I discovered that some are rated for DC and some (most) for AC and yet others don't state anything. Is this a problem or are AC LEDs different from DC LEDs?


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## Penquin (Oct 15, 2007)

I have just replaced some using *Aten Lighting* who have been most helpful and are a company that I would recommend. Their prices were good and they were happy to post direct to me in France - good service IMO.

http://www.atenlighting.co.uk/caravan-motorhome-lighting.html

Replacing the bulbs with LED units is very simple - literally as hard as replacing a bulb as that is all you have to do, unplug the halogen one and plug in the replacement LED unit.......

as a certain TV ad says (repeatedly)...........

simples....... :lol:

Dave


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## mr2 (Feb 26, 2009)

Penquin said:


> I have just replaced some using *Aten Lighting* who have been most helpful and are a company that I would recommend. Their prices were good and they were happy to post direct to me in France - good service IMO.
> 
> http://www.atenlighting.co.uk/caravan-motorhome-lighting.html
> 
> ...


Agree with Dave. Have purchased replacements for all halogen bulbs in my Rapido apart from the extractor. Anyone fitted these as they are not side fitting but need an extra long bayonet?


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## emmbeedee (Oct 31, 2008)

Whiskeymac said:


> In links from a club article on replacing 12v conventional lights to LEDs,
> I discovered that some are rated for DC and some (most) for AC and yet others don't state anything. Is this a problem or are AC LEDs different from DC LEDs?


Well, a diode will only pass current flowing in one direction (LED = Light Emitting Diode). So if you wire them backwards in your motorhome they won't work. Bulbs, of course, will work with current flowing either way. 
I don't see how a standard LED could work on AC. I do, however, have two LED's in our house kitchen (from LIDL) which work fine, so presumably they have some type of rectifier built in to enable them to work on AC. No doubt one of our electrical experts will be along soon to elaborate.

Edited to add:

Most lamps in your motorhome will be wired in the conventional way, i.e. with the lamp body connected to earth. If, however, you have a type where the lamp is fed by two wires, it is possible that they will be connected the "wrong" way for your LED to operate. If this is the case, it will just be the simple job of swapping the two wires over to enable your LED to work.


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## Morphology (Jul 23, 2010)

The first two answers didn't really address your question, so I'll have a go.

First-off, the 12v in your 'van will be DC, so you'll need LEDs that work on DC, but I believe AC ones will also work.

halogens are a filament bulb, so they don't care which way round they are plugged in, and work equally well on DC and AC supplies (though presumably with slightly different light levels?)

The issue with AC vs DC LEDs is (I think) more to do with their use in a domestic situation. Most 12v transformers used for low voltage halogen lighting output 12v AC you if you are replacing the Halogens you'll need LEDs that will operate on AC and also supply sufficient load to the transformer.

When I replaced the Halogens in my 'van, I noticed that although the circuit is DC, the LED bulbs didn't care which way round they were plugged, which leads me to presume that they will also work on a 12v AC supply.

I bought one. made sure it worked, fitted and was the right colour, then splashed out on the rest  

Morph.


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## Addie (Aug 5, 2008)

Whiskeymac said:


> In links from a club article on replacing 12v conventional lights to LEDs,
> I discovered that some are rated for DC and some (most) for AC and yet others don't state anything. Is this a problem or are AC LEDs different from DC LEDs?


AC Current is Mains Voltage and thus not suitable for the 12v lights you have in your motorhome. You can get LED lighting suitable for home use, for example I just replaced 10x 40W spotlights in a kitchen with 10x 4W LED's which provide the same amount of light! http://www.ebay.co.uk/itm/10x6W-GU1...ht_Bulbs&var=510089447402&hash=item4abeb7319f

If you are looking for LED's I would recommend:

1.) Only get 5050 LED bulbs. The others (3258 and 1210) are just not bright enough.

2.) Get as many LED's as your fitting will allow for maximum brightness. You can get 10 for £5.09 delivered if you are prepared to wait 3-4 weeks: http://www.ebay.co.uk/itm/221147748003

That being said there is a new "High Power" type of LED which hasn't yet filtered down but starting to appear on eBay like this:
http://www.ebay.co.uk/itm/190703135983

But just directional at this moment, so probably no good for ambient light.


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## Whiskeymac (Jul 20, 2005)

Yes I know how easy it is to replace them as I've done it before.

Here are 3 links, quoting DC, AC and AC/DC.

DC

AC

AC/DC

Note that the last link states 25v rating but others show a voltage range. Are the 25v ones good for 12v as they are all rated so on this link which came from this website?

Question is, are all these OK for a 12v motorhome, or just some of them?


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## Morphology (Jul 23, 2010)

Addie said:


> AC Current is Mains Voltage and thus not suitable for the 12v lights you have in your motorhome.


Mains voltage is AC. That doesn't mean that AC is mains :!: My Kitchen light transformers step down 240v AC (Mains) to 12v AC.


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## Addie (Aug 5, 2008)

Morphology said:


> Mains voltage is AC. That doesn't mean that AC is mains :!: My Kitchen light transformers step down 240v AC (Mains) to 12v AC.


This is true, of course, but the point I was making is that 12v AC is not suitable for use in a motorhome. You need DC bulbs.


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## Whiskeymac (Jul 20, 2005)

Could we PLEASE stick to the subject of the question posed!


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## Addie (Aug 5, 2008)

Whiskeymac said:


> Could we PLEASE stick to the subject of the question posed!


The answer in several posts - You need DC LED's :lol:


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## gaspode (May 9, 2005)

Whiskeymac said:


> Question is, are all these OK for a 12v motorhome, or just some of them?


I think the easy answer is that they would probably all work OK on 12v DC, the worrying things are:
1) the price you 're considering paying - far too high
2) the diversity - do you want MR16s or MR11s? Or maybe you need some of both?
3) what power output, beam angle and colour do you want?

Any LED lamp with a MR11, MR16 or G4 base will usually have a working voltage of 12v. Some won't work on AC but AFAIK all the LEDs will work on DC (although you may have to turn the lamp round in the holder if they are DC only). Most current MR16 LEDs will work on both AC and DC because people replacing halogens in their houses will already be using AC 12v drivers and don't want to change them.

All mains voltage LEDs will have different bases (GU10, E14, E27 etc). This is a basic safety consideration to prevent people inserting low voltage lamps into high voltage holders.

I've been buying lots of LED lamps recently to use around the house and on MR16s I'm paying less than £3 a unit so my advice would be to shop around a bit. MR11s are a bit more expensive usually due to the fact that they have limited application so aren't produced in such high quantity.


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## Whiskeymac (Jul 20, 2005)

No, really, I'm not considering any of the LEDs in these links necessarily. I am just, only, merely reacting to what I have found on links from a page that I found on this website.

However.

I am aware of some very cheap LEDs, also linked from the same article, from the far east. They may be fine. And now I'm allowing myself to be diverted; I think that it is perhaps as well to heed the warning about cheap LEDs on this website.

LED Fire Risk

Readers of this post might be unaware of this. Personally I take it very seriously, despite an inborn suspicion that scare stories might be used to snare buyers. I've purchased from Bedazzled before as they were very early in this market. There is, perhaps, a price to pay for safety, and perhaps only a small premium.

I am buying LEDs for garden lights where a fire would be annoying but not life threatening. But in a motorhome.....

Thanks for all the views on AC/DC


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## pippin (Nov 15, 2007)

OK - here is something technical.

As previously stated - a light emitting diode has to be connected the correct way round to a DC voltage.

So - how come the DC ones can (usually) work plugged in either way round?

Because there is a bridge rectifier (4 diodes) incorporated into the LED unit.
If you don't know how a bridge rectifier works then you will just have to trust me.

For the same reason it will work on AC.

Now, LEDs are fairly choosy about the maximum current that they can withstand.

Herr Ohm tells us that resistance and voltage and current and watts are all interrelated.

When a LED lamp is rated at 12V it doesn't want anything higher as it will get hot and the LEDs will burn out.

Early LED lamps had a simple resistor to reduce the volts down to something like 2.5V. That is wasteful as heat lost in the resistor.

Since then LED lamps have become much more sophisticated.

Several LEDs will be connected in a series/parallell circuit to reduce the need for resistors.

They will almost certainly incorporate a bridge rectifier.

They have a voltage stabiliser circuit (more efficient than a simple resistor) that will prevent individual LEDs from being overdriven.

Remember that "domestic" MR6/MR11 fittings are driven by 12V AC electronic "transformers" that produce exactly(-ish)12V.

You MH supply, although nominally 12V, can go up as high as 14.5V so that voltage stabiliser really comes into play.

All this more complicated by the fact that some LEDs are dimmable, others not.

So, do you need AC or DC LEDs for the MH?

The answer is that I don't know, even though I am a techno-geek from long abefore the word was invented!

It depends upon what is in the lamp from all the above items and you simply cannot tell from the wishy-washy descriptions usually given.

When I buy a LED lamp I connect it up to a variable power supply that monitors both voltage and current.

I crank the voltage up and down between 9V and 15V and see what happens to the current and the brightness of the lamp.

That is how I find out if it is suitable for the MH.

Well, you did ask for some technical info!


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## Agilityman (Aug 17, 2009)

You can fit DC or AC LED's (because of the in-built bridge rectifier).

The main consideration as Pippin says is: has it got voltage stabilisation for 12v?

Yes - buy, No or doesn't say - stay clear.


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## Whiskeymac (Jul 20, 2005)

Go Pippin....Yeah!!!


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## Whiskeymac (Jul 20, 2005)

Agilityman said:


> You can fit DC or AC LED's (because of the in-built bridge rectifier).
> 
> The main consideration as Pippin says is: has it got voltage stabilisation for 12v?
> 
> Yes - buy, No or doesn't say - stay clear.


It would be good if by the end of this thread there could be a list of recommended suppliers and products.


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## bigcats30 (Aug 13, 2012)

http://www.ledhut.co.uk/

These guys have cheap bulbs (without the wait from china)

But their strip lights are a little expensive compared to what you can get off ebay (none china)

I don't order from China.


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## airstream (Jan 7, 2009)

*China?*

Hi,
We have 19 leds in use on the boat all came from China - where they are all made?

We run at around 13.6 volts on "float" but higher up to 14.5 and lower 12volts when out and at rest

We have had two failures where individual leds have failed

All have cost less than £1 each

I also test each lamp for a while to check for overheating

Just ordered 10 - 24 smd for under £9 Supplied from the UK
will see how they perform ie less than 90p each inc delivery

Ray

PS if your leds are contained in a TUV/CE approved fitting then overheat protection should be inbuilt


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## Whiskeymac (Jul 20, 2005)

*Re: China?*



airstream said:


> PS if your leds are contained in a TUV/CE approved fitting then overheat protection should be inbuilt


Sounds informative but I have no idea what you are referring to. Could you please expand on this subject.


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## airstream (Jan 7, 2009)

*Att.*

Hi,

Link gives details - if your m.h is type approved then all equipment in it will be CE or TUV approved -- most Euro manufacturers have complied for years

Ray

http://www.tuv-sud.co.uk/uk-en/activity/product-certification/european-approvals/ce-marking


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## Whiskeymac (Jul 20, 2005)

Well yes but where does it say that such fittings protect against overheating and how would that prevent the sort of event that is described in the link from post 1329112?


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## gaspode (May 9, 2005)

On the subject of CE marking, don't get carried away with the thought that if it's CE marked it must be OK. CE approval is judged against manufacturer supplied design and construction criteria, not necessarily following an inspection and appraisal of the product.

Having said that, CE approval does indicate acceptance of minimum standards of design and construction so as Ray says should provide some protection when M/H fittings are approved.

But what about the lamps themselves? There do appear to be plenty of LED lamps in circulation that have CE approval so could be reasonably assumed to comply with good design and construction principles. So maybe if you're concerned about the safety of these devices the first thing to look for would be CE approval? If you trawl somewhere like Ebay you'll see that many of the cheap LED lamps coming direct from China claim to have CE approval whereas neither of the UK LED sales sites linked so far in this thread mention CE approval for their lamps. It could be that they just don't mention it but you'd think that they would wouldn't you? :idea: 

Don't ask me how you can judge the quality of an LED lamp from a sellers description, I don't think there's an easy answer, if there is one then I don't know what it is. Take all performance claims with a pinch of salt, comparisons of light output to that of halogen lamps of a given wattage can be especially misleading. One thing I do know is that you most definitely can't judge the quality by the price, some of the worst performing LEDs I've had have been the more expensive ones.

I have a total of 36 LED lamps in use in the house currently and 13 in the M/H. I also had a similar number in the last van and the one before that so I've got some practical experience. In the time I've been using LEDs I have had one sudden failure and that happened within an hour of first plugging it in - it went "phut" and stopped working - no dramas.


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## Whiskeymac (Jul 20, 2005)

Thanks Gaspode. That fulsome tale does of course beg the question of which suppliers you recommend.


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## Agilityman (Aug 17, 2009)

Don't get obsessed with CE marking. CE marking supposed to give the purchaser confirmation that all necessary regulations have been compiled with. However CE marking is self certification. I could produce a article and put a CE mark on it without anyone's approval. Only if the article fails and someone checks it for full compliance will it ever be checked. However I understand if the article marked with a CE mark is found not to comply with European regulations the fines are hefty.


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## gaspode (May 9, 2005)

Whiskeymac said:


> Thanks Gaspode. That fulsome tale does of course beg the question of which suppliers you recommend.


And my stock answer would be (for the M/H) Aten Lighting. Not because they're the cheapest or have the best stock or whatever, simply because I met Saul who runs the company just after he started up and he's always struck me as a decent honest sort of guy who goes out of his way to supply the right lamp for the right job. He's supplied a few to me in the past and I've never had cause to complain.

Having said that, I now always buy direct from Chinese suppliers via Ebay simply because the price difference on larger quantities is too great to ignore. I'm not prepared to recommend any single supplier because I haven't found one that I'd trust 100% yet. My advice would be that if you want to take a punt and understand exactly what you want, buy direct. If you only want a small number of lamps and you're unsure about your precise requirements, go to Aten or one of the other UK suppliers where you can get advice thrown in.


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## Whiskeymac (Jul 20, 2005)

I suppose I should hve posted a link to the post that I have been referring to. Turns out that it was not from Motorhome Facts forum but ukcampsite.co.uk

ukcampsite.co.uk

The energylightbulbs site that it links to is attractive due to free postage, CE approval on products and built in safety fuse but is that voltage rating ok with a 12 volt supply?

energylightbulbs.co.uk


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## Whiskeymac (Jul 20, 2005)

Just taken a quick look at Aten before heading off to bed, thanks Gaspode. Products look very much like those from Bedazzled but a bit cheaper. No mention that I could see of built in safety fuses though.


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## Whiskeymac (Jul 20, 2005)

Summing up then, the consensus is that an ideal LED should have:

Cheap price
A trustworthy seller
CE marking in spec
Sufficient lumens for the task
The desired light: warm or cold
Safety fuse installed
Rated 12v with ability to cope with higher surges
DC rating but AC/DC assumed OK
Free delivery

Free delivery, apart from not inflating the price, permits purchase of a single item for testing, without cost.

I wonder if a built in safety fuse is part of a CE rating.


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## Whiskeymac (Jul 20, 2005)

A few illuminating facts on this website. :lol:

Illuminating website


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## Whiskeymac (Jul 20, 2005)

Reply from Alten:

"Yes, our LED lamps include regulators to protect against voltage surges and include fuses."

Just shows that such facts are not necessarily published.


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