PD IEC TS 61044 pdf free download
PD IEC TS 61044 pdf free download.Opportunity charging of lead-acid traction batteries.
5 Operational procedures
5.1 General
The following information in 5.2 to 5.5 shall be considered when operational procedures are being established.
5.2 Charging conditions
Self-compensating chargers are preferred when opportunity charging is carried out. A correctly sized battery and charger combination is essential for all batteries.
For opportunity charging of valve regulated lead-acid batteries it is essential that only chargers with a current-voltage-time characteristic in accordance with the battery manufacturer’s recommendation are used.
In order to maximize the beneficial effects of opportunity charging, such an operation is preferably carried out only when the fully charged battery has been discharged by at least 30 % of its rated capacity.
This limit is especially important when vented lead-acid batteries are charged with non-self-compensating chargers. Non-self-compensating chargers shall not be used for valve regulated lead-acid batteries.
For intensive energy throughput applications with expected high battery temperatures, opportunity charging shall be initiated only when at least 40 % of the rated capacity has been discharged from the fully charged battery.
An air agitation system of the electrolyte is highly recommended for vented lead-acid batteries in order to prevent acid stratification and to improve the efficiency of the opportunity charging.
Where a known duty cycle exists, a calculation of the energy balance or ampere-hour balance is recommended. The availability of adequate charging time and intervals for opportunity charging shall be verified beforehand.
5.3 Regular charges
The frequency of a regular charge, whereby the battery is allowed to complete its charging cycle and thus prevent premature deterioration of the battery, is as follows:
— for standard vented lead-acid batteries and valve regulated lead-acid batteries, one regular charge every working day. It is possible that this will not be applicable for the scenarios described under Clause 4, list item b) and if that is the case a compromise solution is to be found in discussions with the battery manufacturer.
— for vented lead-acid batteries with air agitation system and especially with valve regulated traction batteries, an interval of up to I week between complete recharges may be feasible.
5.4 Ventilation
During opportunity charging, adequate battery ventilation consistent with IEC 62485-3:20 14 shall be provided. Forced ventilation is recommended unless the opportunity charging is performed in open air.
5.5 Temperature
Elevated battery temperatures cause premature battery ageing and temperature compensated charging is recommended. If during opportunity or regular charging the battery or the electrolyte temperature exceeds the manufacturer’s recommended upper limit, charging is to be stopped until the battery has cooled down to the recommended value. Providing forced ventilation can speed this process up. The resulting airflow shall be vented to the open air outside the building and not carry hydrogen gas or acid mist toward people and sensitive equipment.
Means for measuring the temperature of a battery shall be available to the operating personnel, as well as information on the upper temperature limit set by the manufacturer. The corrosion-proof temperature probe is to be located either in the electrolyte or between cells at the potentially hottest location in the battery.
With valve regulated batteries the electrolyte temperature cannot be measured directly, and the user shall ask the manufacturer to provide the substitute temperature measuring location.
If no other recommendation is available, a maximum temperature of 55 °C for vented leadacid batteries and of 45 °C for valve regulated lead-acid batteries is appropriate.
5.6 Examples of discharge and charge profiles
Figure 1 and Figure 2 show typical discharge and charge curves for vented lead-acid batteries with regular (Figure 1 a)) and opportunity charging (Figure 1 b)) and, for valve regulated leadacid batteries, with regular (Figure 2 a)) and opportunity charging (Figure 2 b)).PD IEC TS 61044 pdf download.
