New SMF batteries have increased efficiency and longer life

Due to the fast pace of industrialisation, demand for more efficient and long lasting SMF batteries has increased manifold

By Kartiki Negi

Tuesday, June 24, 2014: Sealed maintenance free (SMF) batteries or valve regulated lead acid (VRLA) batteries (the latest trends also feature a combination of both technologies –the VRLA hybrid technology) are today widely used in the solar energy, telecom and power sectors. These batteries are commonly classified as absorbent glass mat (AGM) or gel batteries.

Currently, high-integrity tubular gel-topping-free VRLA batteries in solar applications are getting popular among users looking for rugged maintenance-free batteries to beat frequent replacement woes.

The latest in the market

With the increasing pace of industrialisation, the demand for more efficient and longer lasting SMF batteries is growing. A good SMF battery essentially incorporates properties such as a longer lifespan, better manageability, is leak-proof and has higher efficiency in terms of amperage and current delivery. “Monobloc 12 V in the range of 5 Ah to 220Ah, 2 V in the range of 40 Ah to 6000 Ah capacities are generally available in the Indian market,” says Raghavan Sreenivasan, managing director, Southern Batteries Pvt Ltd.

Grid technology: This new technology helps in obtaining thinner grids to hold more active material. This increases the energy density of the batteries by reducing the lead required and, thus, reduces the cost. In January 2014, Artheon Electronics Ltd launched its FT batteries based on grid technology. These are also known as front terminal SMF VRLA batteries, suitable for solar and telecom applications. “These batteries are designed at the C10 rate and are far superior to normal VRLA batteries of the C20 rate. They occupy very little space as these are vertically designed batteries,” says Sunil Bhatnagar, director, marketing, Artheon Electronics Ltd. The grid, alloying and pasting in these batteries play a major role in making them rugged. Prices start from Rs 8000 plus taxes, and these batteries can be used for any industrial application like UPS systems, automation, solar and telecom.

In January 2013, Genus Power Infrastructures Ltd introduced SMF batteries with heavy duty grids and a special alloy. “These are more advanced compared to the conventional lead acid batteries, have very good discharging characteristics and a higher number of life cycles. Their good quality raw material and charging process makes them a reliable product,” says J K Agarwal, director, marketing, Genus Power Infrastructures Ltd.

These heavy duty grid batteries are designed with high precision, meeting international quality standards for C10 rating. They emit less fumes while charging /discharging, and are maintenance free. “These SMF batteries are a good substitute for flooded lead acid batteries and are ideal for applications such as UPS systems, solar power, cable TV, telecom, railways and automotive,” adds J K Agarwal.

Pure lead tin (PLT), thin plate technology: HBL Power Systems Ltd has indigenously developed a battery with high cranking performance using pure lead tin (PLT), thin plate technology. “Electrodes of our PLT batteries are 60-75 per cent thinner than those of conventional batteries. This leads to a compact design and also more electrodes per battery,” says Avnish Arora, vice-president, HBL Power Systems Ltd. These batteries are suitable for gensets, automotive applications, UPS systems, defence tanks, etc. “They offer real value for money for critical applications where high current with a short period of discharge is needed,” he adds.

Gel VRLA: Based on gel technology, Greenvision Technologies Pvt Ltd, has launched a range of pasted plate pure gel batteries in May 2014, which are maintenance free VRLA batteries, targeted for solar and deep cycle applications. The range of these batteries is from 12 V 7Ah to 12 V 240Ah. “These pasted plate pure gel batteries come with charge and temperature protection. The electrolyte is in gel form, which reduces water loss and hence increases battery life,” says Biju Bruno, managing director, Greenvision Technologies. Pvt Ltd.

In December 2013, Amara Raja Batteries Ltd upgraded its existing Quanta range of SMF VRLA batteries for UPS applications, with two new ratings – 12 V 120Ah and 12 V 150Ah. The two newly introduced ratings are designed to be in line with the existing Quanta range, and come with added advantages like a higher energy density-optimised footprint to suit the space available and a built-in high conductivity copper terminal for high rate of discharge.

VRLA AGM technology: In December 2013, Okaya Power Ltd has expanded its existing range of SMF/VRLA batteries by launching OB 200-12 battery with a capacity of 200Ah at C20. “Based on AGM battery technology, these batteries conform to JIS specifications in terms of performance, dimensions and safety parameters. These batteries have pressure-die cast heavy duty terminals to endure high rate discharge,” says Rajesh Gupta, director, Okaya Power Ltd. OB 200-12 comes with a highly AGM separator with low electrical resistance for greater retention of electrolyte. “It has well-designed vent valves to release excess pressure build-up inside the cells, which may lead to bulging/blasting of the battery,” informs Rajesh Gupta. The plate grids are made of specialty alloys—lead-calcium-tin alloy for positive plates and lead-calcium alloy for negative plates. These alloys minimise electrolyte loss due to gassing. Its robust ABS containers are resistant to deformation or bulging, thus exhibiting goods structural integrity.

VRLA hybrid technology: At present, the Indian market is dominated by SMF batteries governed by VRLA AGM technology, while a few players offer VRLA gel batteries. However, the latest SMF version is a combination of both AGM and gel-based technology, and is called VRLA hybrid technology.

In December 2013, Southern Batteries Pvt Ltd launched SMF batteries with advanced VRLA (hybrid) technology. These offer both AGM and gel properties such as longer service life even in high temperature conditions. “These have a lower float current with a significant reduction in water loss. The lower float current ensures excellent performance when operated under a broad range of ambient conditions from Arctic to hot climates. It lowers the stratification effect on tall cells, thereby increasing the cyclic life under PSoC conditions,” states Raghavan Sreenivasan. “Made with hybrid technology, it has been developed to match US, European and Japanese standards,” he adds. The battery is suitable for electric bike applications, UPS systems, solar powered systems, emergency lighting systems, electronic test equipment, medical equipment, etc.

Buying tips

The life of a battery depends on various factors including temperature, overcharging, topping up using impure water and excessive cycling. Hence, it is important to look at all these aspects when making a purchase decision. Today, there is a distinct preference for high-performance, compact and light weight SMF batteries. Thus, consumers should be aware of certain parameters before they go ahead and buy a battery.

Cyclic use or standby use: A buyer must check whether the battery is being bought for cyclic use or for standby use. Both applications have different charge and discharge parameters. The life of a battery is generally quite high in case of standby use. One can select the next higher rating in case of cyclic use, to ensure better results for both backup time and the life of the battery.

Size: The size of the battery takes into account the internal resistance of the battery and its degradation with usage and temperature conditions. Batteries are now available in models that are compact, slim and of low height. This makes maintenance as well as stacking very easy, apart from requiring less floor space.

Temperature conditions: The ambient temperature conditions of the battery should be able to measure temperatures. The SMF VRLA battery is designed to work at 25 °C, so its capacity would change as per temperature conditions.

Discharge rate: Today, SMF batteries are designed for C10 and C5 discharge rates. Earlier, they were available only for the C20 discharge rate.

Electronics Bazaar, South Asia’s No.1 Electronics B2B magazine