The solar charge controller usually has atemperature compensation function. Because As temperature rises,electrochemical activity in the battery increases. Similarly, as temperaturefalls, electrochemical activity decreases. Therefore, as temperature rises,charging voltage should be reduced to prevent overcharge, as temperature falls,charging voltage should be increate to avoid undercharge. In general, to assurebattery optimum service life, use of a temperature compensated charger isrecommended.