February 2010 – Page 2

I bought a cheap charger from DealExtreme for my 18650-size lithium ion batteries. My other cheap charger will charge most 18650’s (though some are probably too long to fit), but it uses a lower charge rate that would take forever to charge up an empty battery. For instance, the small charger uses a 300mA charge rate and an 18650 battery is 2400mAh, so it would take 8 hours to charge that battery at a constant 300mA. And my big flashlight uses two 18650’s and the little charger can only charge one at a time.

So I found this other charger for $7.92 shipped that has two independent charging bays, supposedly charges at 1000mA, and stops charging at 4.20V like it is supposed to.

http://www.dealextreme.com/details.dx/sku.6105

Continue reading “Cheap 18650 Li-ion Charger”

My first impression is that it is smaller than I thought, but also heavier. This is a serious hunk of metal! One nice thing about getting it second hand from a CPF member is the guy I bought it from treated it very well. There aren’t any marks on it that I could see. Plus he made sure to lubricate the o-rings and actually modified the tail switch so that you can halfway press it and the light comes on momentarily (all of my other lights have reverse clickies that you have to click all the way on and then let go before the light comes on; this light has a forward clicky). One of the reasons I got this light is that it had very good heat sinking and comes completely apart. The LED is mounted to a large brass pill that screws into the throat of the flashlight (threaded portion is 29mm diameter and the part that holds the driver is 23mm). The brass carries the heat from the LED directly into the body of the flashlight near its heaviest part. People talk about the light getting fairly hot after using it for a while, and that is a good thing. What would be much worse is the body staying cool while the LED cooks itself. Still, I left the light on for about 15 minutes and it only got warm. It would be pretty neat to be able to buy an extra pill and add my own 21mm driver and LED (maybe a warm P7 or a SST-50), almost like having a drop-in.

Continue reading “Ultrafire MCU WF-1200L”