Trickle charging means
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 rechargi ...
a fully charged
battery
Battery 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
*Automotive battery, a device to provide power t ...
at a rate equal to its
self-discharge
Self-discharge is a phenomenon in batteries in which internal chemical reactions reduce the stored charge of the battery without any connection between the electrodes or any external circuit. Self-discharge decreases the shelf life
Shelf life ...
rate, thus 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 which uses the reversible reduction of lithium ions to store energy. It is the predominant battery type used in portable consumer electronics and electric vehicles. It also se ...
technology, cannot be safely trickle charged. In that case, supervisory circuits (sometimes called
battery management system) 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, possibly to fire or explosion.
References
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Battery charging