Trickle charging is the process of

charging Charging may refer to: * Charging (ice hockey), when a player takes more than three steps before checking an opposing player * Battery charger, a device used to put energy into a rechargeable battery * Charging station, a device used for recharging ...

a fully charged

battery Battery or batterie most often refers to: * Electric battery, a device that provides electrical power * Battery (crime), a crime involving unlawful physical contact Battery may also refer to: Energy source * Battery indicator, a device whic ...

at a rate equal to its

self-discharge Self-discharge is a phenomenon in batteries. Self-discharge decreases the shelf life Shelf life is the length of time that a commodity may be stored without becoming unfit for use, consumption, or sale. In other words, it might refer to whethe ...

rate, enabling the battery to remain at its fully charged level. This state occurs almost exclusively when the battery is not loaded, as trickle charging will not keep a battery charged if current is being drawn by a load. A battery under continuous

float voltage Float voltage is the voltage at which a battery is maintained after being fully charged to maintain that capacity by compensating for self-discharge of the battery. The voltage could be held constant for the entire duration of the cell's operation ...

charging is said to be float-charging. For lead–acid batteries under no-load float charging (such as in SLI batteries), trickle charging happens naturally at the end-of-charge, when the lead–acid battery internal resistance to the charging current increases enough to reduce additional charging current to a trickle, hence the name. In such cases, the trickle charging equals the energy expended by the lead–acid battery splitting the water in the electrolyte into hydrogen and oxygen gases. Other battery chemistries, such as

lithium-ion battery A lithium-ion or Li-ion battery is a type of rechargeable battery that uses the reversible intercalation of Li+ ions into electronically conducting solids to store energy. Li-ion batteries are characterized by higher specific energy, energ ...

technology, cannot be safely trickle charged. In that case, supervisory circuits (sometimes called ''

battery management system A battery management system (BMS) is any electronic system that manages a rechargeable battery (cell or battery pack) by facilitating the safe usage and a long life of the battery in practical scenarios while monitoring and estimating its various s ...

s'') adjust electrical conditions during charging to match the requirements of the battery chemistry. For Li-ion batteries generally, and for some variants especially, failure to accommodate the limitations of the chemistry and electro-chemistry of a cell, with regard to trickle charging after reaching a fully charged state, can lead to overheating and fire or explosion.

References

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