The tests below merely record the APPROXIMATE ratings for these batteries at my testing time. Any battery that is not an authentic Samsung, Sony, Murata, LG, Panasonic, Molicel, or Sanyo has the potential to change unexpectedly! This is one of the risks associated with using "rewrapped" batteries or those from different manufacturers, so it is crucial to thoroughly research any battery you are considering before making a purchase.
Improper handling or misuse of lithium-ion batteries can result in SIGNIFICANT DANGER to personal well-being and property. The use of these batteries is ENTIRELY AT YOUR OWN RISK, like the Efest 18650 2600mAh. They should only be used within a protected battery pack. Never exceed the battery's current rating, and ensure that the plastic wrap and top insulating ring remain impeccable.
Testing batteries beyond their limits is hazardous and should NEVER be attempted by individuals who have not extensively studied the associated risks, comprehended the dangers involved, possessed the necessary equipment, and taken all appropriate safety precautions.
If the battery only displays a single current rating or states "max," it must be assumed that it is rated at that current level for any type of discharge, including continuous release.
Efest 20700 Mooch In Conclusion
The Efest 20700 3100mAh appears identical to and performs virtually the same as some 20700 batteries, a highly efficient cell rated at 30A.
However, the wrap of this cell bears an indistinct and, therefore, meaningless "max" rating of 40Α. Despite my efforts, Efan has not provided any information regarding their "max" ratings, except mentioning the use of pulses lasting a few seconds. No details were given regarding the time intervals between pulses or the criteria for establishing the rating.
The presence of "IMR" on the wrap is incorrect. Eizfan does not utilize the LMO (lithium-manganese-oxide) battery chemistry associated with the "IMR" model number prefix. Instead, it would use one of the chemistries connected with the "INR" model prefix utilized by Moli.
During testing, the capacity of the four cells ranged from 2874mAh to 2944mAh at a current of 620mA (0.2) down to 2.5V. This is significantly below Efan's rating of 3100mAh. The Molicel INR20700A carries a minimum capacity rating of 2800mAh and a typical capacity rating of 3000mAh, so it is frustrating to observe Efan's rating of this cell as 3100mAh.
Based on my assessment, I am assigning this cell rating of 30A and 2800mAh.
Performance Specifications
Average DC Internal Resistance = 19.5mOhms (milliohms) for two cells.
Total energy delivered down to 3.2V at a continuous current of 10A = 7.7Wh
Total energy produced down to 3.2V at a constant current of 20A = 6.8Wh
Total energy produced down to 3.2V at a constant current of 30A = 4.6Wh
Efan paid a fee to expedite their placement in the testing queue, which currently has a backlog of 10-12 weeks. However, this payment does not influence my test results since my approach is rooted in scientific methodology, yielding objective and data-driven conclusions rather than subjective evaluations. Furthermore, they make the payment in advance and have no influence over the content of this report, and it does not matter to me if any company chooses to refrain from such payments or battery donations in the future. Upholding my reputation holds far greater importance than any battery donation or fee to prioritize testing.
