LEDgardener

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!

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?

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

TEKNIK wrote: ↑

Sat Feb 15, 2020 3:12 am

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.

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

TEKNIK wrote: ↑

Sat Feb 15, 2020 4:19 am

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!

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