We have string lights, 30 meters long, 600 LED bulbs, that have started to flicker at quite a high frequency - swapping out the power brick with another brick from a different set of lights fixed the problem, but the power rating is different so I won't use it cause I don't want to cause a fire. They are worth $80 AU so I thought it would be worth hunting down a replacement power brick, if it's safe... cause they are about $20 AU on Amazon

Trouble is, I can't find one that meets the exact same specs, but it seems slightly different models of the same product are widely available, so I wonder what leniency I have with the power ratings, and I was hoping for some direction - is this worth pursuing, or just not worth saving $60 and risk causing a fire...

Here's all the text from the power brick that is failing:

SELV IP20
MODEL: JT-EL/FC24V6W-H4
APP NO: SGS-180670-EA
PRI: 220-240V 50-60Hz 0.12A
SEC:
  U rated=24V~
  U out = 24.8V~
P rated=6W
tc=75°C

When I search for that model code on Amazon, there's a lot that are of the same kind of device (looks identical physically) but all seem to be 31 volts and 40 volts (on the "U out" rating), with the little I know, I think that will overload the wires on the lights and cause a fire. I also saw some that were drastically under the voltage requirement and I know that would cause the LED lights to actually flicker or not operate at all.
https://www.amazon.com.au/s?k=JT-EL/FC24V6W-H4&crid=3280SFIWVBP03&sprefix=jt-el/fc24v6w-h4,aps,747&ref=nb_sb_noss

Is there anything there that would be safe to use? I'm after the Australian socket versions, eg. this one.

What's funny, is when I search for this product online, using the name on the box: "Anko, Low Voltage 600 LED Mulit-Coloured String Lights", I get links to manuals (such as this one) that seem to be from Australia, and sound very much like it's for this product, but they ALL refer to a different code for the power brick: JT-EL/FC31V3.6W-H9, all of them - which is different than the one I have, not sure what to think of that...

 

Here's a photo of the existing power pack, and the packaging of the string lights - I know it says $39 but I think that was a Christmas special from years ago, I saw a similar product online for $79

 

There you go:

https://www.amazon.com.au/PremierAdapter-JT-DC24V-3-6W-IP44-Christmas-A460/dp/B0BN25PFVQ/

On the page you posted, no less.

A 6W supply is pretty lightweight, so almost anything would do the job, if you wanted to cut the old one open and make an adapter to fit your lights. I got my last 24V wall-wart from Vinnies for $2.

 

There you go:

https://www.amazon.com.au/PremierAdapter-JT-DC24V-3-6W-IP44-Christmas-A460/dp/B0BN25PFVQ/

On the page you posted, no less.

Thank you, I had seen that, but the reason I posted is, on my adaptor it says "U out 24.8V~" and on the one you linked, it says "U out 40V" followed by a symbol I can't type - a dash with 3 dots under it. That worries me, I don't want to be supplying 40V into something designed for 24.8V, plus the different symbol must mean something, surely?

I know enough not to put too much voltage into a circuit not designed for it, but I'm not familiar with the specs as laid out on these labels - could it be they are "ratings" that say what they support, rather than what they will output?

A 6W supply is pretty lightweight, so almost anything would do the job, if you wanted to cut the old one open and make an adapter to fit your lights. I got my last 24V wall-wart from Vinnies for $2.

Thanks for the offer - it sounds like the wattage is all I need to worry about? I was sure there was more to it than that...

 

Hmmm - I missed the Uout figure. TBH I'm not sure what it is, or if that matters, but it does seem a lot different to the rated voltage, so your caution is justified. Maybe Uout is the unloaded voltage?? which seems a poor spec to me.

The dash with three dots under means 'DC' rather than AC.

You should be fine with a supply that delivers 24V DC at 6W or more. There isn't much more to it.

 

You should be fine with a supply that delivers 24V DC at 6W or more. There isn't much more to it.

Thank you. Well my eyes have been squarely on that "U out" figure and I haven't seen one that has 24, it's all 31 or 40. It's really annoying.

 

ChatGPT 4o (just released today) told me that the Uout means the device MAY output that amount (40V), but that it's normally 24V, should I trust it?

ChatGPT output below:

To determine if you can safely replace the power supply in the first photo with the one in the last photo, you need to compare several key specifications:

1. Output Voltage (Uout):
   • First power supply: 24.8V
   • Replacement power supply: 24V
2. Current Rating (A):
   • First power supply: Not explicitly mentioned, but the power rating (W) and voltage (V) can help.
   • Replacement power supply: 0.50A
3. Power Rating (W):
   • First power supply: 6W
   • Replacement power supply: 6W
4. Input Voltage (PRI):
   • Both power supplies: 220-240V~, 50-60Hz

Analysis:

1. Output Voltage:
   • The first power supply outputs 24.8V, while the replacement outputs 24V. This 0.8V difference is relatively small and usually within the tolerance range for most LED string lights. However, it's important to ensure your LED lights can handle the slightly lower voltage without significantly affecting performance.
2. Current Rating:
   • While the first power supply does not list the current rating directly, it specifies a power rating of 6W. Given the output voltage of 24.8V, the approximate current can be calculated as:
     Current (A)=Power (W)Voltage (V)=6W24.8V≈0.24ACurrent (A)=Voltage (V)Power (W)=24.8V6W≈0.24A
   • The replacement power supply can provide up to 0.50A, which is more than sufficient to replace the original power supply's current requirement.
3. Power Rating:
   • Both power supplies are rated for 6W, meaning they can provide the same amount of power.

Conclusion:
Based on the comparison:

• The replacement power supply outputs a slightly lower voltage (24V vs. 24.8V) which should be acceptable for most LED string lights.
• The replacement power supply can provide sufficient current (0.50A) compared to the estimated current requirement of the original power supply (0.24A).
• Both power supplies have the same power rating (6W).

Therefore, you should be able to safely replace the failing power supply with the new one. However, it's always good to check the LED string lights' specifications or consult with the manufacturer to ensure that a 24V output is within the acceptable range for your specific lights.

 

The Uout voltage applies only to unregulated power supplies. Ir is the voltage when no load is connected. The rated voltage is the voltage at the rated power.

You can replace an unregulated supply with a regulated one capable of the same current as the unregulated one at the rated voltage.

The current needed is 6/24 or 1/4 A.

I would get any regulated 24V supply at 1/2 A (500 mA) or more. This will be perfectly safe and probably cost less since regulated supplies are far more common than unregulated ones today.

 

Hmmm - I missed the Uout figure. TBH I'm not sure what it is, or if that matters, but it does seem a lot different to the rated voltage, so your caution is justified.

That is the symbol for a DC output voltage. Unfortunately, I can't find anything that says it refers to an output that is specifically either regulated or unregulated.

My guess is that 40 V is the max. compliance of a constant-current regulated output. It would really help to know if the LED string has current limiting built into the string, or if the string relies on the PS to limit things.

ak

 

Thanks guys. So @BobTPH , do you think the one linked to would be safe?
https://www.amazon.com.au/PremierAdapter-JT-DC24V-3-6W-IP44-Christmas-A460/dp/B0BN25PFVQ/

Also I'm concerned about the symbol - the original adaptor has ~ (AC) and the replacement has the DC symbol (with the dash and 3 dots).

So I take it to mean the original adaptor outputs AC and the replacement outputs DC
Which is really odd because the light wire plugs straight into the power pack with no other components, and I know for a fact LEDs do not use AC. Something must be amiss with the labelling here.