Little help needed...

[Cedru]

Little help needed....

Got a Mean Well 320H-36b driver. currently NO potentiometer hooked up to it.

Have 2 cobs, Citizen CLU048-1212 properly hooked up to their heatsink.

When wiring just one cob from the driver, brown driver lead to positive, negative to blue driver lead, the cob powers up brightly.

When wiring BOTH cobs in parallel, both cobs power up.

When trying to wire both cobs up in series, ie. Brown driver lead to positive cob 1, negative cob 1 to positive cob 2, negative cob 2 to blue lead on driver, NEITHER COB powers up.

Any ideas?

Thank you in advance,
*.*.* Cedru *.*.*

 

[Snaddehat]

That driver is suitable for parallel only. It provides 36v and your cobs need 36v each to power up. When wiring in series, the forward voltage of each cob adds together, so in your case you'd need 72v from the driver to power up both cobs in series.

 

[Cedru]

Well that makes a whole hell of a lot of sense. Guess it's in parallel the go, until the new driver comes in.

According to the specs, it pushes out 8090 ma, so I'm guessing I can run 7-8 of these 36v cobs at ~1050ma safely in parallel with this current driver safely, correct?

Thank you,
*.*.* Cedru *.*.*

 

[DrBlaze]

Well that makes a whole hell of a lot of sense. Guess it's in parallel the go, until the new driver comes in.

According to the specs, it pushes out 8090 ma, so I'm guessing I can run 7-8 of these 36v cobs at ~1050ma safely in parallel with this current driver safely, correct?

Thank you,
*.*.* Cedru *.*.*

Yes, when you had only 1 hooked up you were putting all that juice through it. I'd be surprised if it hasn't been damaged. The only way you'll be able to use it with the 2 cobs you have is to get a potentiometer and dim it down.

 

[freemanjack]

Yes, when you had only 1 hooked up you were putting all that juice through it. I'd be surprised if it hasn't been damaged. The only way you'll be able to use it with the 2 cobs you have is to get a potentiometer and dim it down.

Can I suggest this assumption of too many amps is proven to be faulty thinking when it comes to semiconductors. I've no direct data to base this on as I tend to stick with parallel and rated volts and amps but the fact this cob stood being hooked up to 36v @ 8A would suggest I am right in thinking that to overdrive a cob you need to raise the voltage at the same time or the diode just saturates at the available voltage and only accepts the current flow @ that voltage. Certainly need more than the rated voltage to overdrive successfully. Done quite a few overdriven rigs and as long as you adequately cool the sink most top ranking cobs will happily soak up 110-120% drive current as long as you give em the extra few volts too.

 

[DrBlaze]

Can I suggest this assumption of too many amps is proven to be faulty thinking when it comes to semiconductors. I've no direct data to base this on as I tend to stick with parallel and rated volts and amps but the fact this cob stood being hooked up to 36v @ 8A would suggest I am right in thinking that to overdrive a cob you need to raise the voltage at the same time or the diode just saturates at the available voltage and only accepts the current flow @ that voltage. Certainly need more than the rated voltage to overdrive successfully. Done quite a few overdriven rigs and as long as you adequately cool the sink most top ranking cobs will happily soak up 110-120% drive current as long as you give em the extra few volts too.

Yeah now that I look, that driver tops out at 39v which will get you to around 2700ma. If you wanted to burn one of these out you'd have to step up to the 42v or higher. If you ran it at 39v for any length of time you would probably fry the chip though, since it would require very robust cooling at max ma, and the op prob has designed his system to run much lower.

 

[nfhiggs]

Well that makes a whole hell of a lot of sense. Guess it's in parallel the go, until the new driver comes in.

According to the specs, it pushes out 8090 ma, so I'm guessing I can run 7-8 of these 36v cobs at ~1050ma safely in parallel with this current driver safely, correct?

Thank you,
*.*.* Cedru *.*.*

You'll need to connect a meter in series with one of your cobs to see how much current its getting.

 

[VegasWinner]

Volts add up in series amps add up in parallel current is constant.