Appropriate Charging Current For Parallel 18650 Lithium Cells
Answer : There could be some legitimate reasons why this won't work well. These may not apply to you, and if you review the documentation of your charger, you should be able to tell whether these things apply. Probably you are aware that it is not safe to float lithium ion batteries at 4.2V indefinitely. Because of this, all Lithium ion chargers use some method of recognizing end of charge. Typically, end of charge is determined by how much current flows into the battery. For a single 18650 cell, end of charge may be defined as the point where charge current drops to 25mA during the CV stage. But with 9 cells in parallel, it may never drop that low. Which brings me to the second point. Timeout. Many charger IC's will not allow an indefinite amount of time for charge to complete. This is a backup safety in case a defective battery is present, or something else prevents the primary charge termination condition from occurring. Typically this timeout would be set to some n...