What is parasitic loading and why is it important to check this spec in some battery applications?
Parasitic loading means the DC current that flows into the charger from the battery when there is no AC power supply to the charger. In some competitors units the control circuits in the charger are powered from the DC output circuit, so that the charger may “leak” several tens of milliamps (or sometimes more) back out of the battery, if it?s left connected when there is no AC power, or when it’s switched off. This can cause a problem in applications where the charger is normally, or may be, left wired to the battery, when the AC input power is switched off or the supply fails. A load of just 50mA will discharge the battery by 1.2 Ah every 20 Hours, and by 8.4 Ah in a week. If , over time, the battery becomes over-discharged, that can lead to sulphation, or excessively low voltage, so that when the AC power is restored, the battery will not recharge even though power is available. Ideally, the charger should be specified so that the parasitic loading is less than, or comparable to, the
