I recently dismantled a humongous LED bulb that was retrofitted into a large Warehouse metal halide downlight. I've included pictures of the bulb. Basically it consisted of 14 rigid strips which have 58 LED use per strip and around rigid PCB with a ton more LEDs on it.

so I taken all these rigid pcbs off to use them in DIY projects. Can't find any information on them but each set of 58 LED seems to be wired in parallel which would make sense so if one goes out it doesn't take them all out.

How do I figure out how many volts I need to in order to drive each PCB and I'm assuming I need to use current limiting resistor correct? I've never worked with these type of LEDs before so I'm not sure if they work the same as 3M M and 5 m m..

EDIT*** they must be in series... i gave them 34v and they barely light and not pulling any amps yet.... dam.. i was hoping to power these with a couple 18650s... i guess a step up / boost converter
Thanks

 

First question is what DC power source do you have? Ideally a variable one , then just connect one of the strips , start at Zero, and turn it up Till you get a reasonable current ... Since you have a lot of these drive them at a low current and use many strips , they will last longer , give more light out per watt in by doing this .... One strip run at max could be about 3W electrical input (Current x Voltage) it should only be warm not hot ... running each strip at 1W would be better , and less glaring on the eyes to look at ...

If you only have batteries or fixed output use resistor in series for exploring these strips , 100 or 1000 ohms .

You may need over 100V before these light up , there are no resistors on the strip ... to run at a lower voltage the leds would have to be matched for semi parallel operation... If you look very closely at the white face you can see the connecting strips below the surface , from this you can figure out how they're wired . .....58 is only divisible by 2 ... so only 3 options ..All in parallel = 3V (unlikely) ....... two runs of 29 in series = about 90V ...or all in series =180V...

Edit ... you've miscounted 56 on the strips and on the disc .... that creates a new range of possible voltages , I'll let you figure that out.

 

Any figures on original bulb as to wattage & V. Strips have a 120 on them which could mean each LED is about 2W or around 600 mA ?

 

Any figures on original bulb as to wattage & V. Strips have a 120 on them which could mean each LED is about 2W or around 600 mA ?

Just a decimal point out .. written next to the 120W is the chip size "2835" that's a standard size 2.8 x 3.5 mm , max power 0.2W https://en.wikipedia.org/wiki/LED_lamp#Comparison_of_common_SMD_(surface_mounted)_LED_modules

Total number of leds 56x15 = 840 ...If the lamp does consume 120W , that means each chip is driven at 0.143W ... just comfortable.

There's a surprising difference between the efficiencies of different size chips .... 5050's are 70% better than 2835's ... see Wikipedia link above ....

Almost certainly each strip has 4 stings of 14 in series about 45V .. plenty of cheap mains drivers for these on eBay

 

Hey guys thanks for your quick responses.

I was using a DPS 5005 power supply powered by 35 volt. If I connect 35 volts to one of those strips it's not enough obviously. They fainty glow and don't pull any amperage yet...

I was really hoping to use one of these trips and power it with a couple 18650 as a DIY work light.

It always seems like you can never have enough materials on hand for DIY projects LOL I have so much stuff I'm up to my ears and yet I don't have what I need to power please LEDs. I was just Googling on a DIY boost converter to see if I could build something with the materials I have. I came across a few projects of using an Arduino to drive boost converter circuit. Might give that a shot