METHOD FOR DISPLAYING A 'LOW BATTERY' STATE IN ELECTRICAL EQUIPMENT WITH ELECTRICAL ENERGY STORES AND ELECTRICAL EQUIPMENT WITH ELECTRICAL ENERGY STORES WITH MEANS FOR DISPLAYING A 'LOW BATTERY' STATE

摘要

PCT No. PCT/DE96/02396 Sec. 371 Date Jun. 5, 1998 Sec. 102(e) Date Jun. 5, 1998 PCT Filed Dec. 12, 1996 PCT Pub. No. WO97/22887 PCT Pub. Date Jun. 26, 1997In an electrical device, for example a cordless mobile part (MTme), having an electrical energy store (AKK), for example a rechargeable battery or a battery, in order to indicate neither too early nor too late the "low energy store" state in the interest of utilizing the stored energy optimally and in a standard manner for various energy store types and/or different operating conditions of the energy store, use is made of the characteristic that the gradient at the "voltage knee" of a discharge voltage curve (ESK) of the energy store (AKK) is always the same, irrespective of the respective voltage level on the discharge voltage profile. In this case, at least one characteristic variable (STG, KRU)-for example the gradient, the curvature-is continually calculated in the form of an actual value (ISW, IKW) which indicates the characteristic variable in the discharge phase of the energy store. The calculation is in this case carried out, for example, by linear regression. If the actual value (ISW, IKW) is greater than a nominal value (SSW, SKW), then the "low energy store" state is signalled. This ensures that, irrespective of the nature of the energy store and the ambient temperature, the rechargeable battery and the mobile part (MTme) always have approximately the same residual operating time.