Diy Whole Tank Led Lighting Retrofit

[SuperColey1]

Fault test?

If you look at this picture showing you one series highlighted in red:

It looks more complicated than it is in the pictures. It really is quite simple in reality. If one series goes the other four stay one. Just a case of Fault testing the series that failed
Each series is from top to bottom. There are 5 columns each with 3 seperate LEDs. Each series is on a seperate 12V plug.

It all works as you will see later tonight when the missus goes to bed and I can turn the lights off and takes some piccies.

I would just annoy her now but I am blinded and have a headache from the brightness of 15 LEDs. lol


Just for you Rabbut I will show you the first half of the 'sun' sequence (from 3pm to 5pm /1 to all 5 series)

AC

 

[SuperColey1]

I won't be posting pics of the lights after all. lol

Was very careless and connected the wrong +/- on 2 series and therefore 2 drivers burnt out. The LEDs still work though (tested them on one that didn't burn out.)

So will wait for 2 more drivers Aargh the cost. lol and be more careful next time.

Lesson learnt I guess. Take your time Mr C!!!!

AC

 

[rabbut]

Or you could hook-up a conventional diode in there to protect the drivers..... about 5p each from Maplins, get one that will handle the current, and it will simply stop current flow if you connect up the wrong way, or if there is a power supply fault

I see what you mean about it being more simple than it looks. Should still be fun tracing any wires if you diden't know the set-up though, you've got a lot of excess length.... Not a problem though if it works and you're happy with it, you aren't selling them to anyone, so it doesn't matter how easy it is for an outsider to check everything

Hard luck on the burn out

All the best
Rabbut

 

[Schmill]

Bad luck, was looking forward to the pictures.

Definitly sounds like a case for a few diodes though, maybe even an inline fuse for each series if you know current you are providing and can find one to suit

 

[rabbut]

If there is an RCB and a surge protector on the plugs it's connected to (as there should for any aquarium equipment), then there should not be a major enough surge to do damage through the circuit, so in-line fuses should not be needed... The in-line diodes would prevent a driver burnout if they wern't connected properly though, but simply not allowing the current to flow to the Driver in reverse, however, careful connections would negate the need for these too...

All the best
Rabbut

 

[SuperColey1]

Can you explain diode to me and give me a link to what you mean?

I traced the actual problem and it was that on the drivers of these 2 some frayed/stray wires from the + and - must have touched whilst turned on!!!

I am going to stick a bit of insulation tape around any bare wire that is showing.

Ones I did the wrong way round didn't burn out!!! However if diodes will help prevent something I think they will be a good idea.

Next time I do wiring I shall turn the TV off. 1 eye on the wiring and the other watching the FA cup highlights. Doh

Thanks for the input. New drivers should be here in the next few days. They are a UK source. I bought 3 just in case this happens to another at any stage.

Whilst I wait for them I will get all the wiring sorted ready. Maybe get these diodes from Maplins if I know what I am looking/asking for . Then when the new drivers arrive I will just need to solder them into position which is a quick job.

Could I silicon these drivers down to the board when I know they work? Just to stop them moving once the board is upside down?

As I say this is my first electrical project other than simple connecting wires to connectors etc and into ballasts. First soldering attempt etc. So all advice is very welcome and extremely helpful.

AC

AC

 

[Schmill]

Agree that the inline fuses aren't NEEDED, but then again nor are the diodes NEEDED, however this is all if everything is fine and you are careful, and you have it running through an RCD and a surge protector, even in the 'design phase'. A diode would stop the problem of connecting the dc supply the wrong way around and a quick-blow fuse would hopefully stop the problem of a shorted wire blowing it.

AC;

I'd be tempted to silicon the drivers in place, if they don't need heatsinking. Also once your soldering is completed and proven I'd be tempted to blob a bit of silicon on each join to to cover the 'bare' area. Perhaps not needed, but just protects it a bit, and is easily pulled off if you need to resolder for anything.
(In fact I'd probably put little blobs of silicon at points along the rest of the wire too instead of the insulating tape. It will probably hold up better under the warm humid conditions you are going to be expecting)
To prevent frayed wire ends when soldering, strip the wire, twist the ends, tin the wire (basically heat it and feed some solder onto it, you should see it go 'into' the individual strands), then solder to the connection as normal. The tinning will stop the 'strands' and also means you don't need the iron on the LED / Driver for so long when attaching the wire.

The diode is like a 'check-valve' for electricity, it will allow flow in one direction but not the other. However it's also worth pointing out that like a check-valve a diode will affect the flow slightly even when connected the correct way around, (usually a drop of 0.6 or 0.4V).
You'd need to look at Maplins to find out what rating of diode you need as I don't know what current each of your series is taking, (will look at the rest of the thread in a minute, or maybe Rabbut can help with that bit )

 

[SteveyG]

If there is an RCB and a surge protector on the plugs it's connected to (as there should for any aquarium equipment), then there should not be a major enough surge to do damage through the circuit, so in-line fuses should not be needed...

An RCD and surge protector will do nothing to protect the circuit as the circuit is isolated from the mains by the transformers.

Just FYI, shorting the output of the drivers won't damage them as by their nature, they limit the current to 350mA/700mA. Reverse polarity can damage them though although I would not be planning on putting any diodes in there as you do not have enough headroom between your power supply output voltage and the total voltage of your LED string and driver voltage drop.

It's probably a bit late to suggest now, but it is advisable to reduce the LED to driver cable length as far as possible(the best place for the driver is directly next to your string of LEDs) as the inductor/switch/diode/LED loop wants to be as small as possible for highest efficiency because of the high switching frequency and high peak currents. The cable length from the driver to your power supply is not important.

 

[rabbut]

The current flow is small, about 300mA for the 12V supplied if I remeber correctly

This page, item 1N4001G will do the job fine 12p each, a bit more than last time I looked

They have a low foreward resistance, less than 1ohm, but a high reverse resistance, several thousand ohms. Effectively, this allows current to flow forewards and stops it flowing backwards A good diode will not waste a noticeable ammount of voltage in a circuit unless it is one that handles large ammounts of current in both directions

To solder correctly, you would "Tin" both the wire and the connection on the driver. This realy is a 3 handed job, so an assistant (or cloths peg glued to a block of MDF) is realy helpful. Strip the shilding off the wire (only need a cm or two at most of the wire exposed) and then you touch the iron to the wire, quickly followed by the solder. This will put a silver lineing on your wire. Next, touch the iron to the driver contact, closely followed by the sloder. Allow a few moments for each to cool. Next, place the wire behind the hole and apply a light pressure. Next, touch the iron to the contact. The solder over the hole will melt and allow the wire through. It will set thus with no un-shielded wire showing on the revers side. Cut the excess at the joint side with your cutters. Don't apply any more solder, the joint wants to be as "dry" as possible while still giving a good contact.

Silicone over the joints and the drivers will waterproof them as well as gluing them and is recomended during high-humidity applications like this

HTH
Rabbut

 

[SuperColey1]

Can I use any cheap silicon or does it need to be a special one or aquarium one (This will be a sealed unit.) Will normal standard silicon sealant be OK? (the bathroom/kitchen stuff)


Good idea about using it instead of insultion tape

I did tin the wires but with the driver the wire was too wide for the holes so I 'thinned' the wire and this is where the frays appear to be.

Iron? My very old soldering iron is down to the copper!!! I only need it on for a millisecond. I basically just touch and away as quick as and get a good solder that way.

I gotcha with the diode. There is 12V running into each series from the 'regulated' adaptor.

AC

 

[rabbut]

Regulated powersupplies can give slightly more or less current than they specify, depending on their supply voltage. The diodes would be on the supply side to the drivers, not the feed side to the LED's

If the wires did not fit through the contacts on the Driver, you are either using a cable that's low quality, that I would replace in this application, or you are using one that handles larger currents than needed. The latter will reduce resistance and isn't of too much concern, other than that you cannot solder to the Drivers correctly. The Wire wants to be soldered from underneath the board, so only the exposed wire is on the contact side, and the insulated part of the rest of the wire should be butted up to the underside of the PCB onto which your Driver is attached

All the best
Rabbut

EDIT to add, normal silicone in a sealed unit should be fine

 

[SteveyG]

A good diode will not waste a noticeable ammount of voltage in a circuit unless it is one that handles large ammounts of current in both directions

A standard silicon diode (1N4001 for example) will drop between 0.6V and 1.2V in normal operating conditions. At 700mA (your drive current) it'll be dropping just over 0.9V and wasting almost two thirds of a watt which will stop you driving your LEDs properly as your transformer's output voltage is not high enough for this additional voltage drop.

Just double check your wiring before powering up. The last thing you want when you're trying to design a high efficiency system is unnecessarily wasting more power elsewhere!

 

[SuperColey1]

I'm running 5 plugs which are 800ma, 800ma, 900ma, 1000ma and 1400ma. They are all 12V

Would putting more Ma be a problem?

They were just laying around so thats what I used. lol


The wire is standard 2 core cable blue and brown.

I may cut all the wiring back to the LEDs and start again with the drivers close to each unit tidying up and siliconing as I go along.

gluing and siliconing is the way I'll go I think. And turn the TV off so I pay attention plus take my time

AC

 

[SteveyG]

No it doesn't matter, you're not 'putting more' current in, you just have more current available - the drivers take what they need to maintain a constant output current.

 

[rabbut]

The drivers will limit current flow in the circuit, so applying power supplies that can feed more current will should not caurse an issue. A concept a few fail to grasp would be that current is dependant uppon the PD across your components (think voltage), and the total resistance of your components. The stated current ratings of those supplies are maximums, not the ammount they will push

SteveyG, please can you explain how you got to the conclusion that the recomended diode will drop the supply voltage by 0.9V? I cannot see enough data in the spec sheet to work that out, and my knowlage of Diodes tells me that there should be little to no loss through a diode for forward voltage. I am however going on a GCSE electronics and A-level Physics standard of understanding here, along with that that I picked up in 18 months experiince in the Sound and Lighting trade...

While the Surge protector won't pretect the circuit from internal surges, shurely it would protect you from ones caursed by the mains. I can see little risk of an interal surge in this set-up, so shurely we are only looking at the mains feed to it as a caurse of one, or is there something I've missed?

If possible, I'd re-wire with some high quality audio cabling, thats de-oxidised copper with no detectable contaminants. These are used in the audio trade for wireing runs to both speakers and microphones, where current or voltage drops across any lenght is undesireable and potentialy a major problem. These cables are more expencive however...

All the best
Rabbut