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Adrian Jones
08-06-13, 16:48
I think its timely to republish a warning on the use of LED flexible strip lighting on marine craft . This strip is designed for domestic use in our homes, where it is excellent for many applications. . In the home LED strips are supplied by LED driver transformers which provide a constant low voltage output.

If connected to a boat's lighting circuit without a constant voltage regulator an LED strip will be damaged by battery charging voltage (13.8v) and is a potential fire hazard.

Below is a copy of a question asked at a talk I gave at a yacht club and my answer, the content is self explanatory.

Q. 12V LED lighting strip seems perfect for lighting the interior of my boat, are there any issues that I should be aware of?

A. The supply voltage on our boats can vary considerably from a nominal 12V. Boat owners need to be aware of the effect this has on LED strip. It is not widely appreciated that the current passing through LEDs increases almost exponentially as the voltage is increased.

For example, test results for a small length of typical 5050 LED Strip comprising of 9 x 5050 LEDs exposed to a range of DC voltages resulted in the following results:

@12V (nominal battery voltage) I=163mA, bright light

@13.8V (engine running voltage) I=255mA, much brighter light

@16V = (charging voltage, equalisation mode) I=377mA, very much brighter light!

As can be seen, as the voltage increased both the current and light output increased. At 16V the strip was simply too hot to touch after a few seconds. 16V is becoming more common on boats, modern smart battery chargers apply this sort of voltage when automatically running equalisation cycles to even battery cell voltages.

Excessive heat is very damaging to LEDs and operating LED strip at any voltage above its specified working voltage will damage it and at best result in a very significant reduction in the service life of the strip and at worst could result in a risk of fire.

A further point worth considering is that electrical conductors on boats are invariably tinned to limit corrosion, common in damp and often saline atmospheres. LED lighting strip comes fashioned out of flexible copper PCB commonly not tinned. PCB tracks are measured in microns, these strips may not last very long unless very well protected. We have even observed tell tale verdigris type contamination on the so called water-proof variety of the strip, particularly at the solder terminations.

12V LED flexible strip lighting its not really suitable for widespread use on our boats unless a constant voltage stabilisation product is used with it.

The same is true of other resistive controlled LED products.

Care should also be taken in selecting voltage regulators, the cheap ones (series regulators) often use waste more current than the LED lamps they are protecting!!

Regards

duncan99210
08-06-13, 17:06
I've been using cheap LEDs from eBay for years now. Never had any problems with them at all. So I'm not too sure where you're coming from on this. Oh. Wait a moment. You sell expensive LEDs. Ah, problem solved.

claudio
08-06-13, 18:15
The LED strips usually have a 150 ohm series resistor per 3 LEDs which limits the current to about 75mA at 16V
The manufacturer quotes absolute max of 150mA or 300mW per LED
OP quoted for 9 LEDs so multiply by 3 gives 235mA at 16V

Yes they will get warm/hot, (40 to 60 deg C is OK, abs max is 90 degC) but if they are stuck down to an aluminium base plate acting as a heatsink, there should be no problems.
Remember to fuse the LED strips appropriately at around 1A per section and don't rely on the main breaker to protect the installation.

Adrian Jones
08-06-13, 18:18
I've been using cheap LEDs from eBay for years now. Never had any problems with them at all. So I'm not too sure where you're coming from on this. Oh. Wait a moment. You sell expensive LEDs. Ah, problem solved.

I published the figures in order to help people understand the issues in respect of using LED strip on their boats. By having information they can make informed decisions. I'm surprised and disappointed that your unable to comprehend the point I was making. Feel free to PM me and I can give you some free coaching at an appropriate level.

lw395
08-06-13, 20:18
16V will also shorten the life of incandescent bulbs.

It can also cause some '12 or 24' fridges to shut down. Possibly diesel heaters too.

It pays to think before running anything from an aggressive charging system.

I had a play with some cheap LED lamps, the failure mode at excess volts was for the resistors to unsolder themselves! Best not to rely on that, I've known a few circuits keep running with the solder molten.

A cheap cure is to put a bit more resistance in series, the great thing about LEDs is that you can do this and you just get a bit less light, not a feeble yellow light.

sarabande
08-06-13, 20:23
thank you AJ - pro bono publico - always good to hear one of the forum professionals giving free advice.

Rigger Mortice
08-06-13, 21:51
The time is coming when we will all have a single master regulator on our boats which will drive all the LED lighting circuits at a constant voltage. There's little point in having a separate regulator for every circuit.

nigelmercier
08-06-13, 22:02
The time is coming when we will all have a single master regulator on our boats which will drive all the LED lighting circuits at a constant voltage. There's little point in having a separate regulator for every circuit.

Although LEDs need a constant current, rather than voltage, it would still be a good starting point. One of these on each lighting circuit should do the trick, with suitable capacitors and heat sink:

http://uk.farnell.com/micrel-semiconductor/mic29300-12wt/ic-v-reg-ldo-12v-29300-to-220-3/dp/1213493

sarabande
08-06-13, 22:30
If I am going to put LEDs into my small boat (24ft) as cabin and nav lights, will such a device ensure that only a 12v goes to all the units, please ?

And how does it cope with long runs of cable ? Would voltage drop be taken care of by decent size wiring, as usual ?

William_H
09-06-13, 00:55
The question is "has anyone seen any form of resistive current limited LEDs showing signs of distress on firstly an ordinary 14v regulated charge system and secondly a higher voltage smart charging system. (either battery charger or alternator control"
That is any sort of failure let alone actual fire? As far as I know 12v LED lights are intended for a vehicle potentially on 14v charge. olewill

nimbusgb
09-06-13, 07:50
The time is coming when we will all have a single master regulator on our boats which will drive all the LED lighting circuits at a constant voltage. There's little point in having a separate regulator for every circuit.

I have one of these http://www.ebay.co.uk/itm/160661910224 installed for all my lighting circuits. Gives constant, clean 12v even from flat batteries.

CFarr
09-06-13, 07:56
The question is "has anyone seen any form of resistive current limited LEDs showing signs of distress on firstly an ordinary 14v regulated charge system and secondly a higher voltage smart charging system. (either battery charger or alternator control"
That is any sort of failure let alone actual fire? As far as I know 12v LED lights are intended for a vehicle potentially on 14v charge. olewill

Not entirely sure if this was the cause but on the last day of a charter I was helming under engine while the crew cleaned and packed away their gear.
As it was very early we still had the interior lights on.
After about 20 mins my blood ran cold when one of the crew stuck his head up from below and shouted FIRE.
I never want to hear that again thank you.

It turned out to be a very hot LED downlight that had started to burn the wood around it.
Sounds just like the OP's description to me.

Rigger Mortice
09-06-13, 08:44
As far as I know 12v LED lights are intended for a vehicle potentially on 14v charge. olewill

Not necessarily. Some are, some aren't.
Some are designed for domestic/commercial use and are intended to be powered from a mains powered supply. They will be designed to provide the optimum light at output at 12 volts. If over powered then the heating problem can occur.

If designed for car use they will have more leeway. The problem then is, if you use them on 12 volts, rather than around 14 volts, the light output will be reduced.

nigelmercier
09-06-13, 08:58
I have one of these http://www.ebay.co.uk/itm/160661910224 installed for all my lighting circuits. Gives constant, clean 12v even from flat batteries.

That's a nice device, thank you. Just ordered one.