General > General Technical Chat
Christmas tree lights 24v or 26 power supply
(1/4) > >>
MrMobodies:
I had been given this power supply to look at from a Christmas tree light that stopped working.

I plugged it in a draws no load and I put the probes on the dc output and no voltage.


JT-DC24V7.2W-E2

--- Quote ---Urated=24Vdc Prated=7.2W
Uout=26Vdc  tc=75C
--- End quote ---
24/7.2=3.333 amps
26/7.2=3.611 amps
Made mistake with calculation as Zero999 pointed out.
7.2/24=0.3 (300 milliamps)
7.2/26=0.27 (270 milliamps)


I see many of these selling at all sorts of voltages but not with that exact part number or ones with those two different voltages. I have no means of measuring it to find out which as it doesn't power.

I found a video of Bigclive tearing one of these down.
https://www youtube.com/watch?v=5EsnrO45ObA
I opened it last night which is a bit different inside to the one Bigclive tore apart and I see no damage and no smell.
Maybe I will post the pictures later.

Google search:
https://www.google.com/search?q=%22JT-DC24V7.2W-E2%22

The closest I can find is this listing:
https://www.ebay.co.uk/itm/255757493895
CHANGZHOU JUTAI 24V DC FAIRY LIGHT POWER SUPPLY JT-DC24V7.2W-E1 (CH 1199)

--- Quote ---Urated=24Vdc Prated=7.2W
Uout=24Vdc  tc=75C
--- End quote ---
Both 24V.

I am not sure whether the leds need 24v or 26v, what Urated or Prated corresponds to in order to work out the correct power supply and if there are other components that maybe needed on the output as I don't want to blow up the LED'S.

I messaged a few sellers selling them to find out if they sell that exact that model but not response from them.

What do you think?
Zero999:
It's probably current limited. 26V might be the open circuit voltage and 24V the nominal, with the LEDs connected.

You calculation is wrong. It should be I = P/V
MrMobodies:
So I got to find one that is 26v unloaded and 24v loaded or maybe easier, find one that is clamped at 24v with at least a 300ma load.

I'll look at my box of power supplies. I have some adjustable regulators I brought 10 years ago that might do it.

Do you think I better add a fuse if the power supply ampage is significantly greater?
MrMobodies:
I am not sure what to look for and I don' see anything that matches the open circuit and nominal voltage.

I have found something and many like it but I am still confused with the voltages and what they mean:
https://www.savemylight.co.uk/product/self-slt6-350ils-24v-6w-led-driver-constant-current/
SELF SLT6-350ILS 6W LED DRIVER CONSTANT CURRENT


--- Quote ---350mA, 7.5-21VDC,Po=7.35W
Uout=25Vdcmax
24VDC, 0-0.30A,7.2Wmax
--- End quote ---



--- Quote ---SELF SLT6-350ILS 6W LED DRIVER CONSTANT CURRENT
Product Information
£15.99

The SLT6-350ILS is the first revised model of the SLT6-350IL.
These are extremely popular with customers converting mirrors using halogen or ballast transformers to new LED lighting and can also be used with the SELF Touch Dimmers.

The SLT6-350ILS is suitable for:

Constant Voltage 24v lamp connected in parallel at 300mA or 7.2w
Constant Current 1w lamps rated at 350mA connected in series

The product features a built in protection circuit and will shut down in the event of a fault such as: open circuit, short circuit, over load or over temperature. The unit will restart automatically after the fault has been rectified.

This model is commonly found in Dimplex electric fire units to control the lighting.
This is a NON dimmable LED driver.
--- End quote ---

I don't suppose this will be okay?
eti:
TBH mate you can buy a whole new set of lights *including* one of these, for about £6-15 - once the sealed unit is open, it will have lost its safety rating (not sure how these things are rated… “IPXX”?). I’d write it off and replace it if it takes more than an hour to fix, and ensure they’re not gonna use it outside!
Navigation
Message Index
Next page
There was an error while thanking
Thanking...

Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod