SMF batteries: Customised for applications

May 19, 2015: SMF batteries are amongst the fastest moving because they serve a wide range of applications. Manufacturers are now designing application-based SMF batteries, as these offer better recharge and discharge capabilities

By Gunjan Piplani

Sealed maintenance-free (SMF) batteries, also known as valve regulated lead acid (VRLA) batteries, are currently the most popular among the different kinds of batteries available in the market. According to Kapil Sood, managing director, Fusion Power Systems (Amptek), these batteries comprise nearly 75 per cent of the total storage battery market, as a majority of industries use them.

According to a report by Primary Information Services, the Indian market for SMF batteries exceeds Rs 30 billion and is growing at a rate of 25 per cent, year-on-year.

VRLA/SMF batteries have a wide array of applications, which include inverters, automotive industry, emergency lights, solar industry, weighing machines, UPS systems, telecom equipment, emergency lights and small home UPS systems. These batteries are also used in large battery banks for bigger UPS systems, telephone exchanges, telecom signal towers, railway signals, battery-operated motor cycles and scooters, golf carts, solar traffic signals, solar streetlights, solar home lighting systems, windmills, bank security systems, CCTVs, time and attendance recorders, etc.

What’s new

SMF batteries have a wide array of applications. Understanding this, manufacturers are now concentrating on developing batteries exclusively for particular applications along with new technologies.

“The Indian market is predominately loaded with SMF batteries, at present, governed by VRLA absorbent glass mat (AGM) technology. There are few players that do offer VRLA gel battery. I am of the view that the latest SMF version would be the combination of both AGM and gel named as VRLA hybrid technology. Monobloc 12V in the range of 5Ah to 220Ah, 2V in the range of 40Ah to 6000Ah capacities are generally available in the Indian market,” shares Sreenivas.

Southern Batteries’ hybrid batteries, under the brand name Hi-Power. These advanced SMF batteries offer benefits of both AGM and gel properties in terms of longer service life time in elevated temperature conditions; lower float current, significant reduction in water loss; reduced water loss and lower float current eliminate the risk of thermal runaway; excellent performance when operated under abroad range of ambient conditions from arctic to hot climates and lowers the stratification effect on tall cells, thereby increases the cyclic life under Partial State of Charge (PSoC) conditions.

For applications, there is a strong orientation towards the segments that the Indian government is focusing on, which includes solar and lighting applications like LED torches, emergency lights and others.

For lighting applications: The latest in this arena are the SMF batteries for LED torchlights, introduced by Amptek Batteries and supposedly the first of their kind, according to the company. The 4V SMF battery series is specifically used for LED based lighting solutions. Apart from that, the company has also introduced 6V 2.8Ah, 12V 2.9Ah and 12V 5Ah batteries (suitable for American Power Conversion Corporation – APC UPS systems), which were earlier not available.

Other brands, including Regnant Energy Solutions and Artheon Electronics Pvt Ltd, also have solutions for emergency lights.

For solar and wind energy: Targeting the solar and wind energy sector, Artheon recently launched a new range of batteries that are focused on solar and wind power applications, including solar lights, water pumping systems and traffic lights. The new range includes batteries of the following capacity: 12V 8Ah, 12V 80Ah, 12V 120Ah and 12V 200Ah. The company has also launched a range of VRLA motorcycle batteries in 2.5Ah, 4Ah, 5Ah and 7Ah capacities.

“With the changing market scenario, new products are being developed. We see solar as one of the fastest growing categories. There is a new C10 battery range replacing our earlier C20 range in the SMF VRLA space. Artheon C10 batteries are better compared to standard C20 batteries as the user can draw more current in the same time period,” says Sunil Bhatnagar, advisor, sales and marketing, Artheon Electronics Pvt Ltd.

Exide is another company that manufactures batteries for solar installations under its Solatron SGL series. These gel based VRLA batteries are specifically developed and designed for solar photovoltaic applications, can sustain high current discharge and are mechanically rugged.

For electric vehicles: “With the Central government focusing on the environment and contemplating a subsidy on battery operated vehicles, electric bikes and electric rickshaws, this category of automobiles will become very popular in our country as an alternative to auto rickshaws and manually-drawn rickshaws because of their low fuel cost, and less human effort. They may be widely accepted as an alternative to petrol/diesel/CNG auto rickshaws. With the growth of this category, we have launched 12V batteries which cater to electric rickshaws,” says Vikas Aggarwal, CEO, Computech Systems (iPower).

Another player, Southern Batteries has also launched a range of high capacity batteries from 135Ah to 225Ah in 12V SMF series for premium UPS segments and advanced VRLA (hybrid) technology battery for electric bike application.

Making a purchase decision

While buying an SMF battery, consumers will have to bear in mind the applications for which they require the battery and also the energy/load consumption.

“The capacity of a battery determines how long it can run, that is, for how long it can provide power backup. Apart from the type of battery, other important factors must be kept in mind while selecting a particular battery, such as the reliability of the brand, market feedback of the specific product, quality of after sales service, etc. This will ensure peace of mind after the purchase is made,” says Sood.

Bhatnagar adds, “The most important question is what the battery will be used for. This should be clarified before buying it. For instance, a 12Ah UPS battery would work well in a UPS system but not in an electronic vehicle (EV) or Scooty, as the battery is designed for standby use and not for starting, lighting and ignition (SLI) applications. Similarly, automotive batteries would work well in auto applications but not for standby purposes. SMF batteries made in India are more adaptable in Indian conditions and come with better after sales service, so the buyer should focus more on batteries manufactured in India.”

The future of SMF batteries

Going forward, we see brands developing batteries that are more rugged and can withstand strong climatic variations. Moreover, with the expanding array of applications, the need is to develop more and more application-specific batteries.

Additionally, the technological development required includes shorter time periods for charge and discharge of the batteries. Some manufacturers are trying to overcome this limitation in the batteries available today by using thin plate technology. However, this has not proved successful yet.

Boxes

Amptek Batteries’ AT4-4.5 (4V 4.5Ah) battery for LED lighting applications

• Weight: 0.5kg

• Dimensions: 47mm×47mm×101mm

• Low internal impedance

• Tolerant to overcharging

• Can deliver very high current

Artheon Electronics’ 12V battery for solar and wind power applications

• Four to six years expected life under normal float charge conditions at 25ºC (77ºF)

• Extended shelf life: Up to 14 months at 20ºC

• Provides 1300 cycles at 20 per cent depth of discharge (DOD)

• Wide operating temperature range, which suits Indian conditions

iPower’s deep cycle gel batteries for e-rickshaws

• Available in 90Ah, 35Ah and 24Ah

• Temperature range: -25~60°C

• Internal resistance of battery: Less than <=5mΩ

• Constant power discharge: 1.23KW

• Battery performance in 5 hour discharge (constant power or constant current): 18A, end voltage: 10.5V

Southern Batteries’ 6V 10Ah to 12v 235Ah series

• C20 hour rate

• 20 models in this series

• Certification: JISC 8702:2003

• Eco-friendly and completely recyclable after end of life

• Offered in both ABS and PP components with flame retardant (FR V2) options

Standard maintenance tips from R. Sreenivas, managing director, Southern Batteries Pvt Ltd

• Check batteries every three months for any physical abnormalities, including bulges, leakage, cracks, etc

• Measure float voltage of individual units once in three months and record the readings

• Test discharge the battery bank at least once in 12 months to check battery health

• Keep the battery top clean with the help of dry cotton cloth periodically. Inspect the inter-unit connection terminals for any sulphation, etc

• If the battery is placed on steel racks/cabinets, ensure insulation between the battery base and the steel tray. This could be a coat of durable paint or any other insulating material. Steel racks should be well grounded

Avoid sulphation for better battery life

• Consumers should not leave SMF batteries in a discharged state for more than 72 hours. This would cause damage to the batteries partially or completely, due to sulphation. Sulphation is the formation of lead sulphate on negative plates, which acts as an insulator and has a detrimental effect on charge acceptance.

• One should always begin the charge within 72 hours of the battery being discharged.

Key points to consider when choosing a battery

• The application it is required for

• The power consumption level it is required to provide backup for

• Recharge and discharge capability

• Brand reliability, after sales and recycling policy