IEC TS 61044-2021 pdf free download – Opportunity charging of lead-acid traction batteries.
5Operational procedures5.1General
The following information in 5.2 to 5.5 shall be considered when operational procedures arebeing established.
5.2Charging conditions
Self-compensating chargers are preferred when opportunity charging is carried out.Acorrectly sized battery and charger combination is essential for all batteries.
For opportunity charging of valve regulated lead-acid batteries it is essential that onlychargers with a current-voltage-time characteristic in accordance with the batterymanufacturer’s recommendation are used.
In order to maximize the beneficial effects of opportunity charging，such an operation ispreferably 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 withnon-self-compensating chargers. Non-self-compensating chargers shall not be used for valveregulated 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 beendischarged from the fully charged battery.
An air agitation system of the electrolyte is highly recommended for vented lead-acid batteriesin 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 balanceis recommended. The availability of adequate charging time and intervals for opportunitycharging shall be verified beforehand.
5.3Regular charges
The frequency of a regular charge，whereby the battery is allowed to complete its chargingcycle and thus prevent premature deterioration of the battery, is as follows:
for standard vented lead-acid batteries and valve regulated lead-acid batteries，oneregular charge every working day. lt is possible that this will not be applicable for thescenarios described under Clause 4， list item b) and if that is the case a compromisesolution is to be found in discussions with the battery manufacturer.
for vented lead-acid batteries with air agitation system and especially with valve regulatedtraction batteries,an interval of up to 1 week between complete recharges may befeasible.
5.4Ventilation
During opportunity charging，adequate battery ventilation consistent with lEC 62485-3;2014shall be provided. Forced ventilation is recommended unless the opportunity charging isperformed in open air.
5.5Temperature
Elevated battery temperatures cause premature battery ageing and temperature compensatedcharging is recommended. lf during opportunity or regular charging the battery or theelectrolyte temperature exceeds the manufacturer’s recommended upper limit,charging is tobe stopped until the battery has cooled down to the recommended value. Providing forcedventilation can speed this process up.The resulting airflow shall be vented to the open airoutside the building and not carry hydrogen gas or acid mist toward people and sensitiveequipment.
Means for measuring the temperature of a battery shall be available to the operatingpersonnel, as well as information on the upper temperature limit set by the manufacturer. Thecorrosion-proof temperature probe is to be located either in the electrolyte or between cells atthe potentially hottest location in the battery.
With valve regulated batteries the electrolyte temperature cannot be measured directly, andthe user shall ask the manufacturer to provide the substitute temperature measuring location.
lf no other recommendation is available，a maximum temperature of 55 °C for vented lead-acid batteries and of 45 °C for valve regulated lead-acid batteries is appropriate.
5.6Examples of discharge and charge profiles
Figure 1 and Figure 2 show typical discharge and charge curves for vented lead-acid batterieswith regular (Figure 1 a)) and opportunity charging (Figure 1 b)) and, for valve regulated lead-acid batteries, with regular (Figure 2 a)) and opportunity charging (Figure 2 b)).IEC TS 61044 pdf download.