Today i received my WP2 II so i decided to make some test.
I first try the usb output and all seems to be ok.
Then i put into the charger a "trash" battery (a blue ultrafire that i use when i have to test something).
I started with 500ma charging current. After 1 hour the led turn green but after some seconds turn red again and then green... Every 3 seconds the led pass from red to green and then red again after 3 seconds..
Someone know what could be the problem? The battery?
Now i'm charging a TF flames then i'll try with a XTAR battery to see if it happen the same thing.
I had the same problem on one cell with a batch of 20's equal cells. All perfroming nicely but that one. XTAR WP2 charger. MP1 charged it no problem. Tossed the battery since it had intermittent pcb activation in flashlight use randomly by violently shaking the flashlight. Took me a few hour to throughly investigate it.
My advice... toss it.
P.S. That battery also was also performing poorly in current draw. A good one would go 3A easily that one struggled at about 1,7A.
The battery is old and is slowly dropping in voltage when charge current is turned off. When the voltage get below the restart threshold in the charger, it will charge again.
1) Charger starts charging - red, voltage rises, Charger protection circuit on the cell kicking in, and breaking the circuit, therefore causing open circuit, and the charger led to go green, and then the protection circuit resets, and we start again.
2) Very bad cell with super high internal resistance, where a 100mA charge current results in a voltage drop of at least 0.3V. So the cell may be resting at 3.9V, when a 100mA current is applied, the cell voltage rises to 4.20V and causes a termination of charge, which means the voltage very quickly falls back to its resting 3.9V, which is the charger re-start voltage. And the cycle keeps going.
Option 1 requires a charger that exceeds the over charge protection voltage, which the XTAR I can say is not likely to do. Infact the XTAR is one that doesn't really exceed 4.2V at all.
I have a feeling its more option 2, but were talking about a cell which is so bad that it would barely give you any output on med/high for a very short time (seconds) however might give a med/short (minutes to hours) bit of runtime on low low. If your trash cell fits this description, this is most likely the cause.
Here i am again. No problem with TF flames and XTAR cell.. I think it's time to go to the "heaven of battery" for my "trash" battery... It's pretty old and it lost almost 0,8 V in two weeks (from 4.1 to 3,3) without usng it.
Probably other charger are less accurate and don't feel this drop off.
So I got the WP2 today in the mail and it's charging a pair of Eagletac 2400mAh 18650 now. The led on the left bay started blinking green and red. I measured the voltage and it was 4,02v. Put it back in to the charger for some time but didn't see any change. The right bay seems to charge just fine and terminated at 4,21v. Tried to switch batteries and it was always the left one that was red-green-red-green-red-green-red....
So I'm guessing something is wrong with the charger and not the battery :( Any ideas?
Such issues are most likely contact issues, resulting in high resistance --> high voltage "drop".
Try fiddling with the connections, and try again. If this doesn't really resolve it, then its more likely to be a problem with the circuit.
To the charger, whenever it applies power, its voltage goes much higher than that the cell is actually at due to the resistance of the connections, and the high charge current. So it would "see" a high voltage and terminate, and then when current falls, it goes back to measuring accurately, and tries to start charging again.
The WPII tends to cycle at a max rate of about once every 2-3 seconds
I will check the contacts next time batteries need charging. EDC, it's the WP 2 II version and I used the "1" setting. Bought it from this seller at ebay http://myworld.ebay.com/chinaqualitygoods
