Potentiometer

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Well-Known Member
Hi guys

I am building some new lights an I am using 2 hlg 185 1400 drivers. Can I use 1 potentiometer for both drivers or do I need 1 for each ?

Thanks in advance ☺
 
Hi guys

I am building some new lights an I am using 2 hlg 185 1400 drivers. Can I use 1 potentiometer for both drivers or do I need 1 for each ?

Thanks in advance ☺

For 1 driver to get proper range you'd use a 100k ohm pot. For 2 drivers you cut that in half and use a 50k ohm pot. You will also want to add a 5k resistor to the 50k ohm pot.
 
For 1 driver to get proper range you'd use a 100k ohm pot. For 2 drivers you cut that in half and use a 50k ohm pot. You will also want to add a 5k resistor to the 50k ohm pot.

Adding a resistor in series prevents the dimming function going to 0% and prevents some of the flickering issues some drivers have at low settings. Meanwell suggests using the formula 100k/N where N is the number of drivers. In our example of 2 drivers it ends up being 50k and a safe base value for the resistor is 10% of the pot resistance.
 
You won't need a dual 50K, just one 50K for two drivers to allow the one pot to control both drivers. My (bad joke) post about the dual pot should have said "dual 100K". 10K was a typo.
 
Sorry to hijack guys but if I have a 15 320h 2100ma drivers in parallel can I wire all of them to the same pot?

Also which size pot would I use and would I need a resistor too?

Thanks
 
Cool. Just so I have this right. I just wire the 2 drivers to 1 of the circuits ?

You take the 2 positive dimming wires and run them into a 3 prong wago, then run one wire from that wago to your positive terminal on the pot. Then you take the two negative dimming wires and run them into a 3 prong wago and run one wire out to the neg terminal on the pot.
 
Sorry to hijack guys but if I have a 15 320h 2100ma drivers in parallel can I wire all of them to the same pot?

Also which size pot would I use and would I need a resistor too?

Thanks

You don't really want to dim all of them at the same time because it sets you up for problems. I would get five 33k ohm pots and run 3 drivers off each. That way if something goes wrong with a cob it doesn't affect your entire grow. You would add a 3k or 3.5k resistor to each pot to limit your dimming from 10% to 100%. Meanwell suggests you never dim below 10% as it causes issues with flickering and can also ruin your driver.
 
How sensitive are the pots? As I would like to make sure all of the LEDS are pulling equal watts I figured getting the dials equal on multiple pots be difficult?
 
How sensitive are the pots? As I would like to make sure all of the LEDS are pulling equal watts I figured getting the dials equal on multiple pots be difficult?

Then buy 10-turn pots and use your lux meter to dial it in. :)
OK, that might be a little anal.
 
How sensitive are the pots? As I would like to make sure all of the LEDS are pulling equal watts I figured getting the dials equal on multiple pots be difficult?

You can use a kill-a-watt meter or something similar and know exactly what each driver is pulling but instead of buying 5 different kill-a-watt meters you can just use one on each driver and pot at a time and use a black marker pen to put a small mark around the pot knob at intervals of 25% - 50% - 75% etc. Once you have that pot marked move the kill-a-watt meter to the next driver and plug it in, repeat the same steps and mark out your percentages. Now you know exactly what each driver is pulling from the wall at any time.
 
You can use a kill-a-watt meter or something similar and know exactly what each driver is pulling but instead of buying 5 different kill-a-watt meters you can just use one on each driver and pot at a time and use a black marker pen to put a small mark around the pot knob at intervals of 25% - 50% - 75% etc. Once you have that pot marked move the kill-a-watt meter to the next driver and plug it in, repeat the same steps and mark out your percentages. Now you know exactly what each driver is pulling from the wall at any time.


Good idea I'll do that thanks
 
If any of you have experience with cobs and distances required from canopy could you take a look at my thread about it?

I'm in process of buying all the parts for my setup and struggling to work out optimal drive current for use with co2 and height limits so distance from canopy would only be 12-15 inches

Cheers
 
How sensitive are the pots? As I would like to make sure all of the LEDS are pulling equal watts I figured getting the dials equal on multiple pots be difficult?

There are different 'taper' profiles for potentiometers. What I would try to use is a linear taper(resistance change is directly proportional to rotating knob. There are tapers that don't have much change in resistance until rotation of knob is close to max and then change is very rapid. The only way to easily calibrate each knob would be to use a kill-a-watt style meter to measure draw. Then you could make indicators for each pot.
 
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