Multiple Hps Bulbs in Parrallel to Single Ballast

[dehv]

I could see improperly matched capacitors causing poor power factor and increased heat in the ballast. Some examples I've found when it comes to HPS in particular:
7uF (MFD) - 70W
14uf - 150w
and so on up to 55uF for 400w

 

[xtsho]

70 watt HPS? Why bother?. Why not just use the right wattage for your ballast? You want more light intensity not less.

 

[dehv]

for seedlings and clones, or to use lights in the garage perhaps?

again - THEORETICALLY.

 

[Renfro]

I have seen splitters that are designed for this. Dunno what to think about them, seems like a discontinued product. Probably a good reason.

https://www.planetnatural.com/product/ballast-splitter/

 

[Renfro]

Thats a different one, supposed to work with digital ballasts

https://growershouse.com/solis-tek-digital-splitter

 

[Renfro]

FWIW an old thread on the matter

https://www.rollitup.org/t/using-one-ballast-to-run-two-lights.735286/page-2

 

[Renfro]

I was considering using one 1kW HPS ballast running at 1200 watt overdrive to run two 630W CMH bulbs but the more I research it doesn't seem like a good idea.

What if one bulb goes out, would all 1200 watts go to the remaining bulb and toast it too?

 

[dehv]

I was considering using one 1kW HPS ballast running at 1200 watt overdrive to run two 630W CMH bulbs but the more I research it doesn't seem like a good idea.

What if one bulb goes out, would all 1200 watts go to the remaining bulb and toast it too?

Aha! finally a good point! Yes the ballast would provide the full amount of current to whatever it was powering.

To clarify, I'm speaking specifically regarding magnetic ballasts for simplification of discussion.

Having looked over that old thread (thank you!) it seems there is some confusion regarding ohms law on that thread (mostly relating to digital ballasts), but that doesn't apply because:

"HID lamps have negative impedance, which means that the lamp draws more current than is required for it to operate." - Source: 5024_HID_Ballast_Application_Guide

So in my example of 2x70s on a 150 mag ballast - if one dies the other would use the entire current available from the ballast, worst case creating a shit power factor and/or burning out the internal bulb.

BUT in the OP's case, 4x150s, sounds like an even sketchier idea. They couldn't be run in series because that's for splitting the voltage where here we would want to be sharing the current (of the ballast) at the same voltage.

Interesting thought experiment, I'll have to give it a (temporary) whirl on the bench and see.

 

[dandruff]

In this case it's a "use what you got" theoretical more than practical question. Or should I be a big boy and stroke your 1000w cock I can't afford when I have brand new equipment sitting here?

The worst that could happen is it doesn't work, we're not talking about overdriving here. Besides, there's one youtube where a guy overdrives a 70w mercury vapor to some 3000W before it pops (inside the outer bulb).

Like the OP said, why burn your plants or waste light because you have to keep them farther away, when you could use more small lamps and distribute the light evenly over a given area - in this case FOR FREE???

If you can't afford a 1kw lamp you should delay your hobby until you can, or get the bread to buy one. Besides, sometimes there are arising circumstances that happen that call for more $$$ to be spent than a 1kw lamp setup is worth. You need to get your priorities straight bud.