Bid at an auction on ebay and won four of these for ridicilous money and 1 is a complete dud, it doesnt work. Multimeter says 3,8v but it can only produce a dimly glowing LED (what you call halo?) that you can look straight into. Charging it with my WP2 II produced the interesting effect of voltage dropping the more I charged it. Put it in the WF-188 and it made it happier (but maxed out at 3,85). I dropped one on the floor when I unpacked them, don’t know if it’s that particular battery though.
The rest charges to 4,10-4,15v and two of them works OK, one flickers in my HD2010 on high.
Conclusion: If you pay less for four 18650’s and shipping costs from China than you do for a coffee at 7-Eleven, chances are the cells aren’t very good. But I didnt expect anything else. And two of them work just fine (for now).
I made some discharge test with the cheap “Ultrafire” 18650 “3000” mAh batteries I have.
Since I can’t discharge these to 2.8V but only to 3.0V (1A), can I determine the full capacity of the battery?
The results of the discharge to 3.0V 1A, was around 1200 mAh.
That depends on the battery. Some batteries can easily be discharge above 3 volts, some other cannot. Look at the curve, if it is nearly vertical at the end, the battery is fully discharged.
In my test the batteries are not always fully discharged, especially not at 5A current.
I have an original imax B6 charger, I can’t export the results.
According to the battery life in flashlight usage, it must be around 2000 mAh.
Not bad for a “3000 mAh” cell???
And the reason why you're "feeling" it has 2000mAh, is probably because in real life use, the current actually keeps dropping following the battery voltage (assuming normal linear driver).
A discharge test will keep pulling 1A regardless the voltage drop, until the battery drops below the preset target voltage.
How can you tell the difference between the UF 3000 "protected" and non protected cells? I purchased a headlamp that came with two UF 3000s that (surprise, surprise) seem to have significantly different charge times. The batteries are used in a parallel configuration. I am guessing that this will also translate to a significant difference in capacity. I am trying to figure out what I want to do with them:
1. Recycle them? They are brand new and that seems like a waste.
2. Buy 2 pairs of Panny 3400s and just use these if I forget to charge the unused Pannys.
3. Buy 1 pair of Panny 3400s and rotate these with the Pannys.
They claim to be "protected" and they are longer than 65 mm. I held my calipers parallel to the button (but not contacting it - I don't want to risk shorting them). It appears to be about 69 mm long. That appears to match w/the FastTech specs for the protected cell. It looks like the Panny NCR18650B Protected cells are a physical match. I'm going to get a couple of pairs of those, a Nitecore charger, andmaybe something to do controlled discharges on.
Yes, their discharge curve is flatter than some other cells, so they probably wont last as long/provide as much light as some other cells might. Of course, great cells, but not the perfect choice for any condition.
The light is a Cree XM-L T6. The driver? No idea. I'm assuming its the cheapest generic driver sourced out of the cheapest country in the world. The maker is supposedly a company called ePathDirect. Unfortunately, it is just an Amazon construct, so I have no idea where they sourced it from. It is so generic that the headband says "Cree" on it and the battery pack says "LED Headlight".