Reaction, reversible
Chemical reaction that can take place in either direction (oxidation or reduction). The cell reaction must be reversible in order to use a secondary battery
(e.g. charging or discharging a secondary battery).

Rechargeable battery
>> Secondary battery.

Recharging
Creating a fully-charged state from any charged state (e.g. caused by self-discharging).

Recombination
Means by which gases normally formed within the battery cell during its operation are recombined to water.

Recoverable capacity
>> Capacity loss, temporary.

Rectifier
A device used to convert alternating current to direct current.

Red lead (Pb3O4)
Lead compound produced from bivalent and quadrivalent lead oxides (2 Pb0 PbO2). Is used as a forming aid for positive lead masses.

Remaining capacity
The capacity that remains after discharging.

Remaining charge
Full charge from undefined charge state.

Resistance, inner
>> Inner resistance.

Reversal
>> Cell reversal.

Reversible failure
>> Failure, reversible.

Reversible reaction
>> Reaction, reversible.

Rib
Ridges of a separator adjacent to grooves.

Round cell
Round cell, in contrast to prismatic cell.