April 2020

T he tips apply to lead-acid motive batteries, which dominate in today’s electric industrial vehicles. Most are ‘traditional’ flooded lead-acid units that need topping up with water. Others, known as valve-regulated lead-acid (VRLA) batteries, require no top-ups. hese sealed packs divide into gel and absorbent glass mat (AGM) categories. Included under AGM are thin plate pure lead (TPPL) products, with lower charging-related maintenance needs. 1. Read the instructions Along with general maintenance advice, the battery’s instruction sheet or manual will contain detailed product-specific information and action points. Failure to follow specified procedures may invalidate warranties. If you are unsure or for any questions seek guidance from battery professionals. 2. Don’t overfill or underfill In flooded batteries, lead plate electrodes are suspended in a sulphuric acid electrolyte whose level falls over time and must be topped up with water. Note, however, that there should be no watering within the first ten charge/discharge cycles. If the level drops too low, plates can be permanently damaged by exposure to air – reducing their capacity and lifespan. The battery may also overheat. Overfilling may cause acid leakage during the next charge, as the electrolyte expands. Acid loss reduces runtime and can result in overheating – a major cause of poor performance, damage and premature failure in batteries. 3. Check the electrolyte Electrolyte level checks apply only to flooded batteries and tend to be scheduled after every ten or so charges. As the battery ages, increased water consumption may require topping up more often. Check a few cells more frequently to see if this is becoming necessary. In conventional servicing, the specific gravity of each cell’s electrolyte is measured monthly. 4. Watch charge levels Avoid discharging any battery to below 20% of its charge capacity. Excessively deep discharge damages the battery, shortens its life and can make electrical components overheat. On the other hand, recharging long before the charge falls to 20% wastes battery life if you are using the more traditional battery technologies. Advanced lead-acid technologies such as TPPL exhibits better performance when they are frequently opportunity charged and kept at high State of Charge (SoC). 5. Watch the temperature Extreme heat or cold during storage, charging or use will limit a battery’s performance and shorten its life. Refer to the product’s specific instructions for a clear definition of its acceptable and optimum ranges. As a rough guide, never charge a battery whose temperature is below 10 °C or above 45 °C. 6. Keep it clean and tidy Deal with small acid spills from flooded batteries using an approved cleaning liquid. Spilt acid not only corrodes terminals and other structures but may create conductive circuits that drain charge. Wetness can have similar effects on both flooded and sealed packs, so keep the battery, its tray and its surroundings clean and dry. Check all battery and charger plugs, connectors and cables regularly for corrosion, wear and damage, including exposed wires and loose fittings. Checks by an electrical specialist, at least annually, must include measurement of the truck and battery’s insulation resistance. 7. Control recharging times A battery’s capacity declines with age. Its service or cycle life is the number of charge and discharge cycles it can deliver before its capacity becomes non-viable. Each recharge uses up one of those cycles and brings the battery’s end of life closer. In standard lead-acid batteries, it therefore makes sense to delay recharging until the vital 20% charge level is reached. 8. Equalise, desulphate and refresh Variation in voltage and capacity between a battery’s cells may develop. They can be rebalanced using an equalisation charge: a deliberate and calculated overcharge, to a higher-than-normal voltage, typically once every five to ten charge cycles. In flooded batteries, the same process helps ‘stir’ the acid, to restore a more consistent and effective distribution, and removes some of the sulphate crystals from plates. Batteries fitted with an electrolyte circulation system benefit from the mixing action of air pumped into cells. Equalising charges are often applied at weekends, as they add extra time to the charging process and require a longer cool-down. 9. Choose the right charger For maximum battery health and performance, batteries and chargers must be fully compatible in terms of cables and connectors, voltage and current ratings, charging profiles and settings. The easiest way to assure this is by using combinations recommended by the manufacturer and supplier – which are sometimes a condition of the battery’s warranty. Improve your battery and operational efficiency by moving beyond conventional, low-frequency, taper chargers. High-frequency (HF) chargers are more efficient and ‘kinder’ to the battery, with current supply tuned to its needs at each moment. The modular power design of some HF chargers adds further efficiency. To gain full benefit from advanced TPPL batteries, your charger also needs a fast-charge facility. 10. Automate battery management Automated aids to battery management and protection include the Wi-iQ battery monitoring device from EnerSys. This reports in real time on factors such as temperature, voltage balance and electrolyte level. It also gives warnings and provides a useful battery history log for analysis. In larger fleets, the Xinx battery operations management system, also from EnerSys, provides for optimised battery healthcare and efficient use. For further information please visit: www.enersys.com 42 | Plant & Works Engineering www.pwemag.co.uk April 2020 Handling, Storage & Logistics SPECIAL FOCUS Getting the most out of your motive batteries Yanis LOUNNAS - application engineer at EnerSys, outlines ten ways to help you achieve the best possible return on your battery investment.