This charge transfer is due to the mechanical release or closure of the contacts, the contact-to-coil capacitance, and the stray capacitance between signal and relay drive lines.

Analogous to a snow avalanche on a steep mountain slope, an incoming light pulse initially frees just a few charge carriers which in turn free others until the original signal is amplified many times.

When charging below 0.33c (except in BREAK-IN) mode, the batteries may not produce a sufficient end-of-charge signal for the charger to terminate correctly.