Kdest 18650 3500mAh 30A Battery
To eliminate any confusion regarding eGo batteries, I use the term "cell" to refer to individual 18350, 18650, 26650 batteries, and so on.
While the test results offer concrete data, the conclusions and recommendations I make are based on my personal perspective and established criteria. Furthermore, it is essential to conduct thorough research on any cell you are considering purchasing.
Attempting to test cells at their limits is dangerous and should never be undertaken by individuals who have not extensively studied the associated hazards and effective risk mitigation measures.
If the cell bears only one current rating or states "max discharging current," I must assume that the company claims the cell can be discharged at that specific current level, regardless of the discharge method employed.
18650 Li-ion battery Key Point
This Kdest product, similar to the top 18650 batteries, is essentially a rebranded and overstated 10A 3400mAh cell. When it is used at its continuous rating of 15A, the temperature approaches the boiling point of water. The advertised "pulse" rating of 40A is unreasonably high and would cause the voltage to drop to impractically low levels. These Kdest cells have identical performance and appearance to the LG MJ1.
Kdest has marked its metal casing with "MADE IN KDEST," which is notable because this is a rebranded LG cell.
The 18650 ratings table has been updated to include this particular cell. The two compartments were acquired directly from Kdest (Kdest) for testing purposes.
Results of Pulse-Current Testing
Pulse testing was not performed since this is the rebranded MJ1 cell. The test results for the original cell are available here: LG MJ1 10A 3400mAh 18650 Bench Retest Results... a commendable 10A battery.
18650 Li-ion Battery Observations
At a continuous current of 5A, it achieved an approximate capacity of 3100mAh, comparable to the Efest 20700 3100mAh. This represents the average performance of a 3400mAh cell with high internal resistance operating at 5A, which leads me to rate it at 3400mAh.
When operating at a continuous current of 10A, the temperature reached 69°C. This temperature is a few degrees lower than the average for a cell functioning at its constant discharge rating (CDR), suggesting that we may be running slightly below its optimal rating.
At the specified continuous rating of 15A, the temperature soared to 96°C. This value significantly exceeds the average temperature of a cell operating at its CDR, indicating that we are working well above its actual rating. The observed voltage sag is substantial and suggests that its accurate rating is approximately 10A.
At a continuous current of 20A, the cell proved to be practically useless.
I am setting a CDR of 10A for this cell. While operating any cell near its maximum rated current level causes damage, I anticipate good cycle life at a continuous current of 10A.