Do these litle lights need a "starter"?

[JohnW2]

..... Guess I've just been lucky So... are they all going to explode some day, or am I safe...?

If they were the sort of 'cheap' LED lamps I mentioned in my post (after my edit, which probably 'crossed' with your reply!), they would probably have died immediately and, even if they didn't, would have been exceptionally bright (with a short life expectancy). It therefore sounds as if you might be lucky.

Kind Regards, John

 

[Roger465]

If they were the sort of 'cheap' LED lamps I mentioned in my post (after my edit, which probably 'crossed' with your reply!), they would probably have died immediately and, even if they didn't, would have been exceptionally bright (with a short life expectancy). It therefore sounds as if you might be lucky.

Kind Regards, John

So much to know... weeelllll... they were cheap B&Q, but they've been up and running for 2-3 weeks now I suppose.

They're certainly not "exceptionally bright" - a bit less than I expected, to be honest. If it's relevant, I think there is one transformer per bulb - I just used the existing wiring, so didn't change anything...

 

[winston1]

What does it say on the lamps?
If it says 12v 50/60Hz you need the transformer I linked to above, but not one for each light.

https://www.tlc-direct.co.uk/Products/TLT50slash1.html

If it says 12v DC you need this:

https://www.screwfix.com/p/halolite...l+Content&utm_content=TextLink&utm_term=58258

Depending on lamp wattage it will drive 2 or 3 lights.

 

[winston1]

If it's relevant, I think there is one transformer per bulb - I just used the existing wiring, so didn't change anything...

You have one SMPS per lamp (not transformer) and SMPS are NOT suitable. The lamps are not meant to run at tens of kHz.

 

[Roger465]

What does it say on the lamps?

Ummm... 12V AC/DC 50/60Hz...?

 

[JohnW2]

So much to know... weeelllll... they were cheap B&Q, but they've been up and running for 2-3 weeks now I suppose. .... They're certainly not "exceptionally bright" - a bit less than I expected, to be honest. If it's relevant, I think there is one transformer per bulb - I just used the existing wiring, so didn't change anything...

If they've lasted that long, with a fairly normal brightness, then, as I said before, you've probably been lucky.

In case you're interested in "knowing", the potential issue is this ... There has to be something in the lamp to control/limit the current flowing through the LED. In some cheap LED 'lamps' this is essentially just a capacitor - and the thing about capacitors is that the extent to which they reduce current decreases with increasing frequency. If it were designed to work with a toroidal transformer like the one winston linked to, the frequency would be mains frequency, i.e. 50Hz (50 cycles per second). However, as winston said, power supplies like you have usually produce a frequency of a few thousand Hz - much higher frequency, hence much less current reduction and hence an excessive amount of current through the LED. At the least that would result in excessive brightness, but it would probably kill the LED very quickly, perhaps almost 'immediately'.

Kind Regards, John

 

[winston1]

Ummm... 12V AC/DC 50/60Hz...?

Well there you are then. Both my two links will work but not the SMPS you have.

 

[JohnW2]

Well there you are then. Both my two links will work but not the SMPS you have.

... except that we're told that they have been working for 2-3 weeks.

Kind Regards, John

 

[winston1]

... except that we're told that they have been working for 2-3 weeks.

Kind Regards, John

Well perhaps his continued use of them at 800 times the correct frequency has damaged them.

 

[Roger465]

If they've lasted that long, with a fairly normal brightness, then, as I said before, you've probably been lucky.

Me lucky... hhmmm, this is an unfamiliar thing. Not sure how it feels... illusory, probably

In case you're interested in "knowing"

Oh yes, I'm always interested in knowing. It's why I come here

And I understand what you're saying... Two things come to mind: (1) while of course ultimately it's my responsibility to know what I'm doing, if this really is potentially such a problem, it's a bit irresponsible of B&Q to sell LED units and dichroics or whatever they're called together, with the same fittings, and the same stated voltage, reinforcing my idea that they are interchangeable; (2) I'm rather surprised my bulbs (all 13 of them) haven't gone pop...

 

[JohnW2]

Well perhaps his continued use of them at 800 times the correct frequency has damaged them.

I see no reason why frequency, per se, should damage them - whether 800 times or 10,000 times their 'rated' frequency. As I said to the OP, the only real issue I can think of regarding frequency would be that which would arise if a capacaitor were being used in an impedance-critical role.

If the current limiting in the OP's LED lamps were reliant on a simple capacitor, if the reactance of that were 800 times less than it would have been at 50 Hz, I would have expected instant death of the LED element(s), so I imagine that the lamps have a non-frequency-dependent means of current limitation - maybe just a resistor. In fact, if the LED lamps are suitable for both AC and DC, that obvioulsy must be the case, since one using a capacitor (if any ELV ones do - cheap 230V AC ones certainly do) would obviously not work with DC.

Kind REgards, John

 

[JohnW2]

Two things come to mind: (1) while of course ultimately it's my responsibility to know what I'm doing, if this really is potentially such a problem, it's a bit irresponsible of B&Q to sell LED units and dichroics or whatever they're called together, with the same fittings, and the same stated voltage, reinforcing my idea that they are interchangeable; (2) I'm rather surprised my bulbs (all 13 of them) haven't gone pop...

I'm not sure that it is necessarily a potential problem - it is winston who thinks that it is (theoretically) a potential problem.

Given that winston suggested that an 'electronic transformer' was not suitable for LEDs, I explained to you at least one theoretical reason why an LED lamp 'intended' for 50 Hz might be killed by a much higher frequency supply, but I have no idea whether any such lamps actually exist - I frankly rather doubt it - and, as I've just written to him, yours cannot be of that type, since they are said to work with DC as well as AC.

Kind Regards, John.

 

[Roger465]

I see no reason why frequency, per se, should damage them - whether 800 times or 10,000 times their 'rated' frequency. As I said to the OP, the only real issue I can think of regarding frequency would be that which would arise if a capacaitor were being used in an impedance-critical role.

If the current limiting in the OP's LED lamps were reliant on a simple capacitor, if the reactance of that were 800 times less than it would have been at 50 Hz, I would have expected instant death of the LED element(s), so I imagine that the lamps have a non-frequency-dependent means of current limitation - maybe just a resistor. In fact, if the LED lamps are suitable for both AC and DC, that obvioulsy must be the case, since one using a capacitor (if any ELV ones do - cheap 230V AC ones certainly do) would obviously not work with DC.

Kind REgards, John

Beyond my level of electronic competence, but... in a current-limiting capacity (!), is the capacitor simply wired in series with the LED?

 

[winston1]

They have a bridge rectifier for a start which is probably not rated at the frequency.

I have experimented with these lamps at 40kHz and they consume 1 1/2 times the power for the same brightness and overheat.

 

[JohnW2]

Beyond my level of electronic competence, but... in a current-limiting capacity (!), is the capacitor simply wired in series with the LED?

Yes - that's how it is done in cheap 'mains' voltage (230V/240V 50Hz AC) ones - but, as I've recently written, I'm far from convinced that this is ever done in 12V ones, and it certainly can't be done with ones which (like yours) will work on DC (because DC can't get through a capacitor).

Kind Regards, John