duel 250w ballast

[wndsurfr]

I have a duel 250w HQI ballast and I am wondering if I can run one 250w de bulb and one 150w de bulb with it.
Thanks

[chtan]

perfectly okay to do so.

[wndsurfr]

Thanks.
In terms of energy usage is it better to use the 2 de bulbs on the duel ballast or use the 250w and some power compacts?

[chtan]

I wld go with 2 SE if u want a broader coverage of the surface area ....

I don't think u would need to use power compacts unless u want to design something that uses a combi of power compacts and MH and have the MH on for say 5 hrs and the PCs on for another 5 ... that is energy efficient ... but I personally find it to be a bit of a hassle.

U could consider 2 x 175W SE too ... to be more efficient.

And the actinics whether PCs, T8 or T5s u use purely for viewing.

[areze]

can a 400w ballast run 150s or 250s? is the energy consumption less as well?

seems like a 400w ballast is maybe $10 more than a 250 than a 150; why doesnt everyone get 400w ballasts and 400w pendants then run a 150 bulb if they want. so they can upgrade later.

[chtan]

Well, most of the time if some one wants to fix a 150 ... then they will get the next size, a 250 ... also there is a price difference betw the 150 and the 400 .... but if it is only a $10 difference ... why not ....

Another thing is that the 400w ballast is a about 4 times the size of the 150 ... and most of us like to have the ballast in the housing ....

Well, at least that is how it goes for me. :rollface:

[scottfarcuz]

I have seen this asked several times and the answer was always no.

You can now run a 250w bulb on a 400w ballast??? Is this just true for the DE/ HQI ballast?

[scottfarcuz]

A few examples...

http://archive.reefcentral.com/forums/showthread.php?s=&threadid=656589

http://archive.reefcentral.com/forums/showthread.php?s=&threadid=579700

[chtan]

scottfarcuz ....

I m going to check w some one more technically competent on using a 150w on a 400w ..... esp about the exploding part.

But I have used a DE 70w on DE 150w ballast and 150w DE on 250w DE ABB ballast from germany ... and it works fine.

areze - apologies in advance if I gave u wrong info about the 150w being able to work on the 400w ballast.

[cparka23]

You do realize that you're overdriving all your bulbs by running them on the wrong ballasts, right? Kill the life of the bulb, and the trade off is you get a brighter light. Considering how much the difference in price is between a 150W and 250W bulb (what, $10-15 USD), that's just not smart. Think of an LED/Christmas tree light on a std power outlet. The light is brighter for a half-second before it burns out and starts smoking. NOT a good thing to try with MH, esp. around water.

[Herbert T. Kornfeld]

Halide ballast's wattage need to match the bulb wattage. Running a 150 on a 250 or 400watt ballast is not safe.

[chtan]

I have checked with some one who designs and tests these things; it is possible to run a 150w on a 400w.

But given the general view here that it is not safe, I agree it is not safe esp if u do not know if the ballast are compatible ...


Even with similar wattage ........I have tried Indonesian made ABB HQI 150w ballast on an 150w AB bulb and it wld just not fire up ... I have also tried other OEM brands from china and it wld not fire up or if it did, it did not fire up as well ..... so compatibility cld be an issue.

I have also had same 150w ballast running 150w light bulb (supplied by the factory) and the MH started smoking after being used for a couple of mths (one of those chinese brands).

[cparka23]

So you're concluding one of two things.. either there are rampant hardware compatability issues or it ISN'T practical to match wattage for ballast and bulb pairs, right?

Yes, it's possible to run a 150W bulb on a 400W ballast. Basically, any MH bulb is just a sheet of glass around some filament and gas. It's obviously not smart to do it though. It's definitely not 'perfectly okay to do so.'

[chtan]

cparka23 ... since the general opinion is that it is not safe then it is not safe because though it is possible to use a 150w on a 400w ballast, there may be compatibility issues .... and then there is the other matter of same for same wattage to ballast ......

so I would not want to see some one else do this and actually have problems.

But after making the last post ... I went to check the 70w and 150w ballast I had (the ABB ones) and they are essentially the same.

For the time being, I will refrain from making those changes to ballast and bulbs ... just keep the ones I have .....:fish1:

[chtan]

Originally posted by jdieck
As far as I know it is not possible or manufacturer recomended. A ballast circuit is designed with the particular bulb characteristics in mind as a single whole circuit. (Like certain wattage speakers for a certain wattage stereo, larger speakers = lower sound and loss of fidelity. smaller speakers=distortion and burn out of the core coil)
Similarly a larger bulb = change of lighe ouput and chromatic lenghtwaves changes if start up at all, smaller bulb = burn out of either the ballast of the bulb.
A MH bulb changes electrical resistance during the startup process and as it ages. A ballast is designed to provide for a constant Voltage and Current (Volt-Amperes) for a given Bulb load despite those changes in electrical resistance within certain range. If the electrical resistance is significantly different (say the resistance of a 150 vs a 400 watter) the ballast will not be able to adjust thus the smaller bulb will receive a lot more juice (power) than it really needs ( usually same voltage but a lot more Amperage) resulting in a tripped breaker, a burned ballast, a very very shortened bulb life and/or or a bulb explosion.

I know of ballast for Fluorecents that are designed for different bulb capacities and configurations like the electronic ballast used for T-5 or the 440 and 660 IceCap for NO and VHO bulbs but none for MH.

I was in another thread ... still mulling about the 150w to 400w ballast issue and I decided to ask jdieck ....

And this was quite a good explanation .... just wanted to share with you.

[xtrstangx]

Electronic ballasts can run different wattages, AFAIK. I'm not sure if a 150w would work on a 400w though, too much of a span perhaps? I'd email the manufacturer of your ballast and ask them to get a definitive answer.

[cparka23]

Chtan, that quote is the application of ohm's law. jdieck's reasoning is correct here.

When dealing with any electronics, you have to account for the total resistance of the circuit. If you are dealing with a 150W bulb on a 150W ballast, you get current going through the circuit (and the bulb) within specifications of the bulb. If you use a 400W ballast on that same bulb, you are more than doubling the current going through the bulb (assuming resistance stays reasonably unchanged as temperature rises). With that increased current, you are greatly increasing the heat produced within the bulb. THAT is why you can have issues with burning bulbs, shattering bulbs, etc. It is certainly not unsafe because of 'compatability issues.' If compatability issues keep your bulb from firing on that mismatch of ballast and bulb wattage, then you should consider yourself lucky.

As far as your two ballasts being similar, of course they're essentially the same. The difference between the two is merely capacitance and resistance - not a whole lot else to my knowledge. As I said before, you CAN do it. You can also survive hitting your fingers with a hammer. Is it wise to try either? Most people would say "no, of course not." Overdriving your bulb that hard is just as ridiculous as someone smashing his/her fingers to see if it'll hurt.

I would advise you to seriously stand behind the advice you give to anyone. For all we know, wndsurfr might have stopped reading this thread after your second response to go setup his bulb-overdriving HQI lights. Be careful to know the facts (and even basic physics, if necessary), before you give out bad advice that can cause injury and/or property damage. If wndsurfr has friends out there, they should check on him to see if he hasn't hurt himself yet. I'm kidding... or am I?:hammer:

[chtan]

cparka23 - understood and agreed ....

nobody is infallible :rolleye1: