The finish is more important than the color. Simply having an anodized finish will increase the thermal properties. However it has anodizing has very little effect on actively cooled fans.
So they are completely different lamps...not a passive or active version of one design. This is a completely loaded and skewed question.
Please, elaborate upon your reasoning with examples or something because my brain is totally fried tonight... I want to understand how passive cooling would be more effective and what it would take in order to reach that ideal that you hold so high.
I feel like shazzam would be something MJ would say...hmmm, a black widow a-tron
What i'm getting from the 50w h/s stars is that they are good enough to save the lamp (at least @ low current) but perform very well once some airflow is applied. I'm more concentrating on making some sort of additional use of the airflow. As it stands , just catching the top edge of room fan is enough.. 156w cobs + 1 driver = buds !! shazzam!!
Simplicity=simplicity!
The poll was meant to examine response between two "ideas", one being a budget quality fanned lamp, meaning emitters running at manufacturer recommendations (which watt for watt would still outperform bulbs in my estimation) and a basic fanless lamp with double the emitters running at half the current. That that particular passive design would outperform the active design is obvious, and would be fanless which has it's own merits. That is what I presented in the OP, not someone elses idea of what a lamp should be... not necessarily the only two options I'm looking at either. If you check Opticgrow's website, they're not offering V29 lamps at anything less than 1.7A.
err, I'm sorry, I don't know what came over me!Wow, Taz, you just took it there!
?temps.. I'd give the 100w radial h/s a try with 1400ma (thinking CXAs), we all have some airflow in tents or rooms. Personally, starting out (as a buyer), everyone seems to come here looking to cheap out as much as possible, X number of single high output cob units would be feasible with higher currents (you mentioned) & to fit a budget, ufo style/ kessil, hard to enclose (without adding a fan) perhaps??.. a downside, reflectors & lenses, smaller designs than you have planned but would seem to fill a niche..
I'm still not convinced that the theoretical passive design would outperform the active simply based on the idea that you have more emitters all ran at a lower current... again, proposing a few details on the possible designs between the two approaches (active vs. passive) would help break it down better for others to understand and ultimately voice desires in what they may or may not want to see in a COB-fixture..The poll was meant to examine response between two "ideas", one being a budget quality fanned lamp, meaning emitters running at manufacturer recommendations (which watt for watt would still outperform bulbs in my estimation) and a basic fanless lamp with double the emitters running at half the current. That that particular passive design would outperform the active design is obvious, and would be fanless which has it's own merits. That is what I presented in the OP, not someone elses idea of what a lamp should be... not necessarily the only two options I'm looking at either. If you check Opticgrow's website, they're not offering V29 lamps at anything less than 1.7A.
I've been building 300w lamps recently at what I consider the middle ground, running them at 1.4A with a fan. I like the design, and the performance is nice for the price. Maybe that will end up being what I decide on. I was hoping this "simple" poll would help me in that regard
@Tazbud I'm getting typical temps at the test point on those radials w V29s @1.05A. Not bad right?
That's true, but when you include the weight of the enclosure the difference isn't as great as you might think.
Depends on the design. The way I'd do it, difference would be great.
Again you miss the point of my post; we, as viewers and pollers, don't know what design you're working on. In other words, without knowing the proposed size of a given heat sink that would be part of a passively cooled fixture, and without giving us some knowledge of how many COBS would be implemented, there's no telling what route would be the better one.
Testing with a 12oz radial design I'm cooling 38 watt emitters to typical temps. Would be nowhere close to 10kg.
Yeah radial are much better suited for passive cooling. Typical temps means Tc=85°C ?
All that stuff is interesting, especially here and in a DIY context and I don't mind getting into it, but it wasn't really the point of the post. Estimated cost and efficacy is all that's needed to answer what was intended to be a simple poll. One of those lamps I wouldn't consider building anyway
(though I could), but again, not the point. I don't think the average customer will be concerned with the size of the heat sinks or how many COBs there are, except maybe that more COBs = better, which I did mention as a consideration.
