Basic battery questions

Hi,


I have a Meco flashlight that has been doing me well for several years, but recently it has been doing a little flickering and dimming from time to time. I tightened the piece in the end cap that has the switch on it, but that didn't seem to help. I was swapping out between 2 UltraFire batteries carrying one as a spare and using the other one night, then charging the one I had used to put it as the spare and using the one that had been the spare the next night. On some nights it worked perfectly and on other nights is was less consistent. Tonight I got looking close at the batteries and the one that works well is a little but noticeable amount longer than the other. I checked the other extra batts that are lying around and the good one is longer than any of them. Can anyone explain that, and how to get more of the slightly longer type? They all say UltraFire BRC 18650 3000mAh 3.7V li-ion. The only difference I see is that the longer one has UltraFire printed on the back end of it and none of the others do. Are the others some sort of fake, and if so how to get the real deal instead?


Thank you for any help with this!
David

First things first, take any and all ultrafire batteries to the nearest recycling center and get rid of them. At best they are utter crap and at worst they are dangerous.

For the sake of batteries 101 acceptable brands include and are limited to Sony, Panasonic, Sanyo, LG, and Samsung and that's it. If you buy unprotected cells for lights that have over discharge warning/protection they will be from one of these brands. If you buy quality rewrapped and protected cells they will have a cell from one of these brands.

Once we get past batteries 101 we can move on to other brands that are not these but are useful in situations.

+1 Don't buy batteries with the word, "fire" in them! Heed staticx57's advice!

staticx57 said:

For the sake of batteries 101 acceptable brands include and are limited to Sony, Panasonic, Sanyo, LG, and Samsung and that's it. If you buy unprotected cells for lights that have over discharge warning/protection they will be from one of these brands. If you buy quality rewrapped and protected cells they will have a cell from one of these brands.

Once we get past batteries 101 we can move on to other brands that are not these but are useful in situations.

Click to expand...

Regardless of whether you get past 'Batteries 101', I would always get batteries from one of these manufacturers if possible. There may be some situations where you can't due to a lack of availability (like if you are looking for 26650s). But when it comes to 18650s, there really isn't any reason to NOT buy cells from Sanyo/Panasonic, LG, Samsung, or Sony. Quality cells are just WAYYYY too cheap these days to justify buying junk.