KL3 vs KL1. Help me understand the differences and other ramblings.

I have just ordered and received a new KL3 head with the frenzel optic. I am amazed at the brightness of the head. With an advertised runtime of 4 hours on two cells and 7 hours with 3 cells is just amazing and almost unbelievable.

Without doing the research to figure out why, it appears that the KL3 is more efficient providing light for a much longer period of time on a given number of cells (two or three) than the KL1. The KL1 is advertising 3 hours on two cells. Why does the KL3 give you an additional hour?

I see that the lumen rating is less for the KL3, 19 vs the 25 for the KL1 so I'm sure that has an impact on runtime, but shining them side by side against a white wall shows almost no difference in brightness (other than tint).

Based on what my eyes see, and the info advertised for each head, why would anyone buy the KL1 over the KL3, other than the obvious size factor?

I think there are several things to consider here. First of all, one head fits e-series bodies and the other fits p-series, so you are talking about two very different animals.

Take someone with a 6P or 9P, for instance. They have bright options coming out their ears. P61 and P91 lamps are very bright for their size, and a LED head is not going to be able to compete in a brightness game. So, I think, the logical choice for these lights is something with a decent output that has a LONG runtime (something that the incan bulbs can't give).

Now, look at someone with an E2O for example. Put the KL1 head on there, and you can increase brightness (maybe a little at least) AND give them a longer runtime. Or for someone using the MN03, you increase their runtime a lot, while not killing their output.

You have to keep in mind that double the lumens isn't percieved by our eyes as double brightness, but just a slight increase. Also, lux III are more efficient (here, I mean output more lumen/mA) at lower drive levels. So a slight decrease in the mA draw is a very slight decrease in percieved brightness.

The last thing to consider is this, KL3 is meant for 2-3 cels, so its a buck circuit in there. KL1 is made for 1-2 cels, so its a buck/boost circuit. I'm guessing the buck is more efficient than a buck/boost, since I thought they both draw around 350mA stock.

schiesz

buck/boost converters are indeed less efficient than buck converters typically. Also, another thread mentioned the output of both KL1 and KL3 heads is 30 lumens.

I've been thinking about getting the new KL3 head with freznel (sp?) optics. I'm not a big fan of the TIR optics and the concentrated spot and always wanted SF to produce a LED light that had good throw via a bright hotspot while provide spill light I could use for close and medium range use. From the descriptions, it sounds like the freznel/ring optics creates the spill I was hoping for. However, I don't have any P/C/M-series bodies. I like the way the Z2 looks, but don't want to purchase the light just to replace the head. If they came out with a KL1 with freznel/ring optics, I'd like that.

jsr said:

However, I don't have any P/C/M-series bodies. I like the way the Z2 looks, but don't want to purchase the light just to replace the head.

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That's what the BST forum is for! Or Lighthound. I just got a C2 body last week on BST. Its just a HA Z2 Body with a big pocket clip. Lighthound charges $39 for that Z2 body.

schiesz