Grow light controller - 30 600w HPS

Hi,

I am planning to build a grow light controller for my greenhouse. I have 30 600w 230v HPS grow lights, will 4 Opto-Isolated 8 Channel Relay Board AC250V 10A ; DC30V 10A run it?

Thanks!

there is a dude named weedpharma around here who can probably help

did you say you wanted to run 30 bulps, each x 600w @ 230v

As you require 30 outlets at 600W and have 32 outlets available you have enough relays.

The question though is how are you going to drive them?

Weedpharma

600W at 230V is less than 3 Amps each, so the relays should be fine. Each relay can switch 3 lamps if you want to do it that way.

What kind of "control" do you need? Are all of the lights going to go on & off together, or will they be individually controlled?

Then are you going to use a timer, or some other control?

Greensprings: there is a dude named weedpharma around here who can probably help

did you say you wanted to run 30 bulps, each x 600w @ 230v

Thanks for the comment but I am but a dwarf amongst Giants.

Weedpharma

What is HPS lamp?
If high pressure sodium you will find they draw quite a bit more than their rating initially.( up to 6 times)
Also 30 of these at your rated 600w would cause quite a drain on the power supply system, and being I assume on 1 phase, you may get a calll from your local supply authority regarding out of balance loadings.

Possibly growing hydroponic “tomatoes”. :wink:

Weedpharma

Hi, I agree with bluejets, 30 x 600 = 18000W or 18kW. That's a lot of heat and you can't just plug them into a wall outlet.

You will need a qualified sparkie to do your work.

Tom..... :)

Thanks for replys!

This is a commercial greens and herbs operation. Power outlet will be done by professionals Tom :wink:

Greensprings: Yes I mean 30 bulps.

weedpharma: Will be using ballast which is apart of the reflector.

DVDdoug: The controller is manly to turn on and off lights. When lights is on a motor is going to move the lights back and forward. In spring/autum only go on if it’s cloudly to save power.

bluejets: Yes, high pressure sodium. And thanks for the heads up!

I’d be using 4 pole contactors.
You can drive them with your smaller relays if they have high voltage rated contacts.

Reason being, I think you will find the high inrush will blow your smaller relays if not immediately, then after a very short number of cycles.

4PoleContactor.jpg

So I would go HPS-ballast -> 4 pole contactor -> relays -> Arduino?

bluejets:
Reason being, I think you will find the high inrush will blow your smaller relays if not immediately, then after a very short number of cycles.

Correct, these lights are known for their high inrush.
I’d be sure to use some heavy duty relays, not some… flimsy Ebay- relayboard.

To reduce total inrush it is also best to turn lights on one by one instead of all at once.

One thing to keep in mind as well is that you are artificially creating seasons.
If a relay welds its contacts because of high inrush, it won’t turn off when you command it to.
Plants will get light 24 hours a day and since most plants react on amount of light/darkness, it could ruin your crop.

Having “played” with a single 400W HPS lamp (eh… tomatoes :-), I would suggest a solid state relay since it can’t weld its contacts, but I lack the knowledge to give you good advice on a 18KW project.

Hi, I agree with the sequential switching ON of the lights to reduce inrush, the arduino would take care of this provision.

Tom.... :)

We had a similar application with metal halide on a sport oval and the requirement was to sequentially turn on each pole (3 lights @750W) due to local electric authority rulings and the inrush mentioned.

Turned out to be quite a programming experience (moeller easysoft) as the requirement was "conditional" in that whatever pole set was first initiated, the others would wait their turn. (8 pole sets in all) 20a- 4 pole contactors are still hanging in there to my knowledge after 8 years.

Can you use different lights? That seems like an awful lot of power you’ll be consuming. The wikipedia page says that LED lighting is used for this purpose - is it economically viable to replace the HPS lighting you have to reduce the power draw?

Yes and No.

Some plants just require 2 narrow colorbands of red and blue light to grow, LEDs are indeed perfect for that.

Other plants need broader colorbands, which can be hard to achieve with leds, some ledpanels even use up to 11-15 different types of leds to get close.

HPS and Metal Halide lamps emit much wider colorbands, best would be to mimic sunlight as good as possible, which can be done with plasma lights, but those are quite expensive.

it sounds like a typical greenhouse application. all off the shelf parts.

600 watts at 230 volts is ... 2.6 amps. not much for a 10 amp relay.

I think the inrush on HPS lamps is not 2x running amp. that is for wirewound (magnetic) for electronic ballasts, there is no inrush. http://www.holophane.co.uk/technical-guide.html

also, since there is an air gap of sorts, luminaries do not act like a dead short. the contacts will not weld on start. I too would look into compatibility of a SSR to use instead of a Form A contact. (Form C has a wasted pole in this application.)

as for the starting, most facilities like retail stores and warehouses do not stage the lights, they use a lighting contactor that brings all (2 to 12 ) circuits into power at the same time. the only restriction is the mains feed.

yikes ! 12 pole is not cheap ! http://www.grainger.com/product/SQUARE-D-Light-Contactor-2MNC6

I use the GE CR463 that has (up to 12) pluggable blades at half that price.

Simpson_Jr: Yes and No.

Some plants just require 2 narrow colorbands of red and blue light to grow, LEDs are indeed perfect for that.

Other plants need broader colorbands, which can be hard to achieve with leds, some ledpanels even use up to 11-15 different types of leds to get close.

HPS and Metal Halide lamps emit much wider colorbands, best would be to mimic sunlight as good as possible, which can be done with plasma lights, but those are quite expensive.

this project will be expensive. the breaker panel, moving dollies for the lights the fixtures, motion cable rated for amps is not cheap, has to be multi strand.... I would hope that all the color band engineering was done well in advance. it would be a shame to spend huge $$ on utility bills when most is not used.