ACCUMULATOR CAPACITY INDICATOR

Radio Record, Volume II, Issue 1, 20 July 1928, Page 13

ACCUMULATOR CAPACITY INDICATOR

SSUMING that the acid in a lead accumulator cell is of the correct specifie gravity, the terminal voltage of the cell may be taken as an indication of the state of plates; thus a fullycharged cell has an E.M.F. of just over 2 volts, which falls to 1.8 in the discharged condition. A voltmeter may, therefore, be used to indicate the condition of an accumulator, and this ‘principle has been made use of in a new aecumulator: capacity indicator. The seale, instead of being calibrated in volts, is subdivided into three ‘regions marked "Low," "Medium," and "Full," each band being given a distinctive colour. A simple test revealed that the red or "Low" region covers a rangé of 1.5 to 1.7, the orange or "medium," 1.7 to 2.4, and the’ blue or "fnll,’" 2.4 to 2.7 eolts per eell. The Jatter range, representing maximum ‘potential, is for use while the battery is on charge, and indicates when the charge should be stopped, YPhe LT. type gives ample warning before the filament current runs down, and the Ii/D. type must be the means Of saving many accumulator H.'T. batteries from ruin; toe often a battery ig left in service until signals fade away and three or four complete discharges of this nature are sufficient to damage the small plates beyond repair,