Modeling Lamp Halogen Bulbs

CooperDragon Sicko
Staff member
I just ordered a few new halogen lamps to test out as replacement for the PAR38 bulbs I tend to use. I picked up some halogen bulbs for photography lighting which are very cheap. They don't have built in reflectors and have a tube shape so I wasn't sure if the spread would be wide enough. I hooked them into my dome fixtures (10.5'' brooder from the farm store) and have been pleasantly surprised. The first one I tried out is a 250w and is just way too powerful at any reasonable distance. Dimming it works but so much power is cut that it isn't a great option since I try to get the wattage pretty close to begin with.

The second one I tried came in a set of 2 (only $5.50 each) These are 150w versions and have a surprisingly good heat spread from the dome fixture. I'm reading 80+ degrees in a 21'' diameter. Hot spot is around 110 and the fixture is 26.5'' off the ground. Incredibly bright white light and little to no humming sound when dimmed.

In my enclosure I'm having more trouble getting the temps adjusted. The fixture is at 26.5'' above the floor of the tank (about as high as I can set it safely) which is about 20'' above the basking logs. The temps on part of the logs started reading around 145 when I let it run at full power. The Herpstat is dimming it down to 45% most of the time to keep the temps on the center of the basking log 100-103. It dims well but starts to give off a little bit of buzz when brought down that much. I moved my UVB fixture out in front of it a little to deflect some of the heat and that helped. It is still providing a nice gradient across the tank, it's a matter of eliminating some hot spots right in the center.

These aren't perfect but may warrant some further testing as a possible cheap alternative to the bulky, short lived, and increasingly hard to find halogen flood bulbs. If I could get my hands on a 100w version I think we'd have a winner. I'm definitely going to keep this set up in one of my portable lamps with a slide dimmer. I'm going to burn them in for a while and see how they look after a week or two of normal run time. Since Darwin hasn't been using his enclosure it's a good time to do some testing in it.

CooperDragon Sicko
Staff member
Original Poster
These might be a really good option for setups that have the basking light shining through metal mesh top and need a bit of extra (dimmable) power.

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