That's what is coming out of the cells. Emitter draw is harder to measure and requires soldering before and afterwards. 1600mA is almost certainly losing a fair bit as heat. 4.2V is well past the Vf of the LED so I suspect the driver is dumping quite a bit of that as heat. You'd need to ask one of the guys round here who knows about electronics about that - my knowledge could be printed out and comfortably inserted into my eye.
The OP light says the emitter is a Cree P4 so around 1000mA Cree spec but you should get away with 1200mA in short bursts without cooking the LED. 1400 if you have really good heat sinking.
So if I take the resistor approach - I guess we're talking about at least 2W resistor? Preferably 3W I guess.
If I know the internal resistance of the battery / battery pack - can I calculate the current I'll get through the resistor? If so, I may be able to pick a resistor such that it will work well with both battery configurations.
Couldn't find a suitable driver, though I searched qutie a bit. Seems that drivers whose max output is below 1A are taking only 1.5V input, but maybe I missed something.
Got some great news for you Haggai I received the extension ring and like yours it doesnt fit... BUT I was so frustrated to fit an 18650 into c30 that I figured it out! 18650 fits C30 without extension ring! You just have to remove the tailcap spring and unscrew the ring that holds the switch. Now you have almost 1 cm more space and 18650 fits without a problem! Just try it! And to make things even better (at least for me ) the extension ring fits onto another 3xAAA light that I got.
I really love my C30 now - its really small for a 18650 light - a whole 1 cm smaller than already quite small Trustfire TR-801 + its a zoomable light. Now if I could only somehow fit a QTC pill in it and it would be a perfect light for me. The led did turn a little blue (from 6 months on 14500 DD), but with QTC and improved heat transfer (thermal grease) I dont think it would be a problem anymore. Size comparison:
I was wondering where you guys got the extention ring and after hearing it doesn't fit ....ah .. never mind ...:~
I like my c30 if that is even what it really is ?? ..I have no idea what emitter is even in it but it's pretty warm and it's a 3 mode ..I still think it's a great light partially because of the tint ..maybe also because it was my first real led light
I think I am going to buy some more of this c30 like flashlights now - they are very cheap here - 4,9$: http://www.buyincoins.com/details/zoom-focus-3-mode-aaa-cree-led-flashlight-camping-light-product-2780.html + they are 3-mode + you can get -15% from that price with code (10%eBay110 and Recommender = nissius). I know that probably I wont get a cree emiter, but just because of the price and possible 18650 mod this seems a really good deal. Did anyone already bought this flashlight from Buyincoins? Is it any good?
It's not Cree Q5 but Osram Golden dragon instead. At least a batch from a month ago was that. I've made complain and they say I either return item or partial refund about 1/3 of a price.