Results for Lumatek Dimmable Ballast

[denverhoss]

Thanks to amonchak for a used 400w bulb to play with.

Below are my very unscientific results for the Lumatek Select-a-watt 400W MH ballast using an old 400 watt bulb.

Ballast Setting Bulb Watts Lux x 100 volts PF Watts/Lux
Lu 400 250 Rad 400 275 24 123.5 0.99 11.46
Lu 400 250sl Rad 400 294 27 123.5 0.99 10.89
Lu 400 400 Rad 400 432 43 123.5 0.99 10.05
Lu 400 400sl Rad 400 450 45 123.5 0.99 10.00

The lux reading is a cheap lux meter placed at an unscientific and sub-optimal location, so the lux level here should only be compared to the other levels in this one chart, I just wanted to see how much visible light change there was. This applies to the W/lux as well, it's all cr^p except to compare within this chart. I did not bother trying to find a PAR meter, partly because I'm using very old bulbs, and partly because I'm still not convinced that Pine Trees and Corals need the exact same frequencies.

You can see that the ballast is pretty efficient if we assume that the 400W setting is actually delivering ~400W to the bulb. 32W being wasted in the balast sounds fine to me, they definately don't get as hot as my old magnetic ones do. But I have no way to determine what the bulb is actually getting, my wattage shown here is just what I measure going into the ballast with my Killawatt.

 

[denverhoss]

I'm attaching a screenshot of the tests since the table didn't format well above. I'll also try to insert it in the text. The table shows the results for my test of a Lumatek 250 Select-a-watt as well. It also has some test of the Lumatek 400 with a 250w bulb.

Two things I saw. With a 250w bulb, the Lu 400 did not changed wattage or lux between the 250w setting and the 250w super lumen settings. The vendor told me I'd need a 400w bulb to see that change, and they were right. The other thing that surprised me was how inefficient a big bulb can be when run at lower wattage. The 400 looks fine running at 250w, but it would be much better to change bulbs to a real 250 when you drop down in wattage. It's hard to see from this chart, but when I put a 175w bulb in at 175w setting, it produced much more light than the 250w bulb running at the 175w setting. I didn't record all those test results and should have, but it was remarkable.

 

[Dave & Monica]

Good read and info - I didn't even know you could fire up a 250W bulb at 175W. Where did you pick up the Lumatek?