SilverFox
Flashaholic
Jasonck08 sent me one of these cells to check out. Over the past 2 months I have been running it through a series of tests and have found that it is a very good cell.
Let's get into the details...
The cell came with a protection circuit, so I charged it up and ran some tests on it. As you can see, the protection circuit tripped during the 4 amp discharge.
Capacity was lower than the labeled 3000 mAh (it actually came in at 2496 when discharged at 0.5 amps), but more on this later.
Here is the graph of this protected cell.
The specification for these cells calls for charging to 4.35 volts, and the 3000 mAh capacity is rated at a 0.2 amp discharge rate with the cell being discharged down to 2.75 volts.
Following the specification, I ended up with 2999 mAh. Wow, not bad.
At 4 amps, I noticed the cell was warming up, and it got hot during the 6 amp discharge. It would probably not be a good idea to continually discharge at 6 amps or above, although the cell would probably handle it a few times.
I stopped my testing at 6 amps because I wanted to determine if the cell could really handle being charged to 4.35 volts without damage to the cell.
Here is the graph of the bare cell.
After this testing was complete, I then ran the cell through 20 charge/discharge cycles charging at 3 amps to 4.35 volts, and discharging at 3 amps to 2.75 volts. At the end of this cycling, I ran another discharge at 0.2 amps, and it came out to the same as the first discharge at 0.2 amps, so no damage was done.
I then charged the cell up to 4.35 volts and let it sit on the shelf fully charged for 2 weeks. The discharge at 0.2 amps showed only a very slight change in capacity but not enough to indicate much damage.
At 6 amps of discharge the midpoint voltage was about 3.3 volts. It is nice if a Li-Ion cell can maintain a midpoint voltage of 3.5 volts, but at higher loads, the voltage drops off. The discharge rate for this cell holding a midpoint voltage of 3.5 volts was 4 amps. The mid point voltage during the 0.2 amp discharge was 3.85 volts.
These cells give you about 84% of labeled capacity when charged to 4.2 volts, which should greatly extend their cycle life, or full capacity if you have the ability to charge to 4.35 volts. You will have to contact Jason to figure out how to get a hold of some of these cells. The protection circuit adds some size to the cell. The bare cell is a typical 18650 cell. Jason has the details on the protection circuit, but it would be ideal if it could be set for a discharge rate of 6 amps.
All in all this is a strong cell. I am not sure what the advertised cycle life is, but I put over 50 cycles on it and there is very little change in capacity. I may have to try some higher discharge rates to see where things begin to break down, but on the other hand I may just use the cell in one of my lights...
Tom
Let's get into the details...
The cell came with a protection circuit, so I charged it up and ran some tests on it. As you can see, the protection circuit tripped during the 4 amp discharge.
Capacity was lower than the labeled 3000 mAh (it actually came in at 2496 when discharged at 0.5 amps), but more on this later.
Here is the graph of this protected cell.
The specification for these cells calls for charging to 4.35 volts, and the 3000 mAh capacity is rated at a 0.2 amp discharge rate with the cell being discharged down to 2.75 volts.
Following the specification, I ended up with 2999 mAh. Wow, not bad.
At 4 amps, I noticed the cell was warming up, and it got hot during the 6 amp discharge. It would probably not be a good idea to continually discharge at 6 amps or above, although the cell would probably handle it a few times.
I stopped my testing at 6 amps because I wanted to determine if the cell could really handle being charged to 4.35 volts without damage to the cell.
Here is the graph of the bare cell.
After this testing was complete, I then ran the cell through 20 charge/discharge cycles charging at 3 amps to 4.35 volts, and discharging at 3 amps to 2.75 volts. At the end of this cycling, I ran another discharge at 0.2 amps, and it came out to the same as the first discharge at 0.2 amps, so no damage was done.
I then charged the cell up to 4.35 volts and let it sit on the shelf fully charged for 2 weeks. The discharge at 0.2 amps showed only a very slight change in capacity but not enough to indicate much damage.
At 6 amps of discharge the midpoint voltage was about 3.3 volts. It is nice if a Li-Ion cell can maintain a midpoint voltage of 3.5 volts, but at higher loads, the voltage drops off. The discharge rate for this cell holding a midpoint voltage of 3.5 volts was 4 amps. The mid point voltage during the 0.2 amp discharge was 3.85 volts.
These cells give you about 84% of labeled capacity when charged to 4.2 volts, which should greatly extend their cycle life, or full capacity if you have the ability to charge to 4.35 volts. You will have to contact Jason to figure out how to get a hold of some of these cells. The protection circuit adds some size to the cell. The bare cell is a typical 18650 cell. Jason has the details on the protection circuit, but it would be ideal if it could be set for a discharge rate of 6 amps.
All in all this is a strong cell. I am not sure what the advertised cycle life is, but I put over 50 cycles on it and there is very little change in capacity. I may have to try some higher discharge rates to see where things begin to break down, but on the other hand I may just use the cell in one of my lights...
Tom
) - and 4.3 reached. No really, it's safe using the 12V side plug.
