2 QB 120s in series on an hlg-120h-c1400a

[Animatey]

Hey guys,

Big fan of the site, have used the info to create 3 DIY lights that I've been very happy with!

Right now I'm using 2 vero 29s B version on an hlg-120h-c1400a in a 2x2 tent.

My vertical height is limited in my 2x2 grow tents and I've been light stressing my plants when they grow into the COBs.

I was looking at what boards I could use with my drivers (I have 2 of the same light mentioned above, each used in it's own 2x2 foot tent) and the only ones I think would work are the qb120s. The 132s look good but 2 of them wouldn't fit in my 2x2 tent... In fact 2 of the 120s will barely fit...

So I emailed hlg and they said I could put 2 qb120s on my driver (HLG-120H-C1400a) in series. This would barely fit in my tent, but I'd be willing to try it...

Based on what I've read here, there isn't enough vf with the 2 boards in series to meet the drivers minimum voltage.

24 * 2 = 48
48 < 54 ...

Am I missing something here? Why would the driver work outside it's constant current region?

If it helps I probably wouldn't run the driver above 100 watts, maybe 120 at the most.


Thanks for reading!

[Animatey]

Ok so I read this article:

https://ledgardener.com/exceeding-volta ... t-drivers/

I'm wondering, can I just add a 5 ohm resistor in series and bring the total voltage drop into range for the constant current mode?

Obviously this isn't something a person might normally do, but if I'm trying to reuse drivers I already have would it make sense?

Would the resistor get real hot?

[TEKNIK]

Do you have a data sheet on the boards you want to use

[Animatey]

Do you have a data sheet on the boards you want to use

This is the closest they have to a data sheet:


https://horticulturelightinggroup.com/p ... rd-guide-1

Thanks for taking a look.

Would like to do 2 in series, but the vf is only 22 at 1.4a and my drivers constant current region is 54 to 108 volts.

[TEKNIK]

The forward voltage won't be high enough. It's better to buy another driver

[Animatey]

The forward voltage won't be high enough. It's better to buy another driver

I thought maybe the driver just wouldn't run in constant current mode, but I'm looking at other options. Thanks for taking a look!

[Sinfor]

You can use the 120H without the resistor but you won't get more than 62W