Quality Lithium Ion rechargeable cell made in Japan
Maximum Capacity and Reliability
Maximum Constant Discharge Current: 20A
4.2 volts max voltage and 3.6-3.7 volts nominal voltage
Button top: Yes
Dimension: (D)18.50mm*(H)66.50mm
Weight: Max. 49.0g
For once I did not use my 2.8 volt cutoff, but discharged down to 2 volt (This is the lower limit for these batteries).
The battery has no problem delivering 20A.
Conclusion
The battery can be discharged down to 2 volt, but the voltage does compare favorable to other LiIon batteries with a higher end voltage. Using a cell from LG I will call this a very good high current battery.
Recharge from 2v, safely? Did I read that right? They will all recharge from 2v, its just not recommended normally due to shunts or whatever. Why is this one different?
All LiIon manufacturers experiment with the exact chemical and physical construction of the cell. This cell is obvious slightly different in composition, allowing a lower voltage.
I did search for data sheets to confirm the 2 volt, but did only find a rev 0 data sheet on google, that specified 2.5 volt. I hope Keeppower has more up to date information.
HKJ can you ask a confirmation from KP on 2.0 volt ? maybe it was a typing error as you know they have made typing errors in the past, some quite serious.
The cell is rated to 2.0 volt "end voltage". This is specified for both 0.5A discharge and 20A discharge.
Maximum continuous discharge is also specified as 20A, i.e. if Efest is using this battery their specifications are way higher than the cell manufacturer says.
Somehow I missed this review, Thanks HKJ!! Didnt' realize these KP's are LG cells.
Just got 2 pairs of the LG HE2 cells in yesterday from FT. They compare pretty much the same as the Efest 35A cells - exact or within 0.01A of each other in a light with the Nanjg FET based driver (direct drive). I was getting 5.69A on the LG's, and best I saw was 5.70A on an Efest 35A, Sam 20R, and Powerizer. In a Super Shocker, they did 6.08A - best I got on the Super Shocker was 6.20A with 2 Efest 35A's and one SONY VTC5. It's all so close, within any reasonable margin of variation of charging level, test setup, etc.
These are sooo close to Sam 20R's, with the 20R's dying quick after 30 secs, dunno, these cells seem to be a great alternative with a better discharge curve and longer runtime. Just use HKJ's comparator (http://lygte-info.dk/review/batteries2012/Common18650comparator.php), and compare the 20R to the KP IMR 2500 and look at the 5A discharge curve....