Solar batteries are of the really deep cycle type, providing energy storage for solar, wind and other renewable energy systems. Unlike a car battery, a deep cycle battery is capable of surviving prolonged, repeated and deep discharges
By Belal Khan
Selecting a proper battery for solar photovoltaic systems requires a complete analysis of the battery discharge requirements. The factors taken into consideration while sizing up the battery are operating temperature variations, environmental temperature extremes, weekly/daily usage, the voltage regulator design and the efficiency of the inverter. Also, the energy required to charge a battery will be the sum of the previous discharge energy output and the energy expended as work and excess heat during the recharge. Longer charge times and lower charge currents tend to increase charge efficiency.
In lead acid batteries, turnaround energy efficiency can approach 85 per cent. Shorter charge times and higher charge currents will come at the expense of energy efficiency and battery life. The charge time and power available from the solar array must therefore be considered when selecting the battery type and size.
The battery’s operating life in the solar PV system is a function of the operating temperature, the duty cycle, the depth of discharge, the charge control and the cell design. A significantly higher average operating temperature decreases life, and the number of available charge-discharge cycles decreases with increasing depth of discharge.
Featured here are some of the latest renewable energy batteries in the market.
Products available in the market
Product: Solar battery – 20Ah/12V-220Ah
Su-Kam batteries, are built to last longer and are rugged enough to be used in any weather conditions.
Homes located in remote areas without access to grid power often depend on off-grid renewable energy systems to meet their power requirements. In such cases, energy systems designed to store solar, wind and hybrid power play a critical role in providing uninterrupted power when the sun doesn’t shine or the wind does not blow.
Su-Kam Solar batteries are designed with a C10 rating and are engineered for the long life requirements of off-grid/hybrid and DC based systems as well as residential systems. Home owners can optimise their renewable energy systems and dramatically reduce operating costs when powering their homes in remote areas—whether they use solar panels, wind turbines, or a combination of different sources in a hybrid system.
- Su-Kam Solar batteries are designed at a C10 rating for deep discharge performance
- They have the capacity to sustain a partial state of discharge
- The Ah efficiency of the battery is >90 per cent, whereas the Wh efficiency is >= 75 per cent and the endurance test meets IS 13369:1992 standards
- Operating costs are quite low; hence, it’s pocket-friendly
- Su-Kam Solar batteries need water topping twice a year unlike other batteries which need this at least four times or more, annually
- These solar batteries are MNRE approved
Okaya Power Pvt Ltd
Product: ST150H (150Ah)
Okaya solar batteries offer a low self-discharge rate, good performance, durability, higher current and power efficiency. Major applications of such batteries include solar inverters and solar domestic lights or streetlights, apart from many others.
- Designed cycle life at C10 discharge (at 27°C, 1.85V PC)
- Ultra-low maintenance due to low antimony content
- Good ampere-hour and watt-hour efficiency
- Ultra-low rate of self-discharge
- Ideal for cyclic applications due to superior voltage and energy output profile
- Designed to operate in partial state of charge condition
- Micro porous ceramic vent plugs with water level indicators
Fusion Power Systems
Product: Amptek 7.4V 4400mAh Li-ion battery
Storing solar energy is simpler with a rechargeable lithium-ion battery. In a power outage, users have a backup source of energy for their lights and appliances.
Amptek lithium-ion batteries are used in the following applications and services:
• Electric vehicles
• Solar, LED lights
• Emergency lights
• Security systems
• UPS systems and switchgear
- Over charge protection
- Over discharge protection
- Cell under voltage protection
- Over voltage protection
- Short circuit protection
- Over current protection
- Reverse polarity protection
Sealed Energy Systems
Product: Solar streetlight batteries
Sealed Energy Systems’ Solion product line comprises compact, lightweight, rugged and dependable Li-ion battery solutions. The company has put in tremendous efforts to create battery solutions for off-grid solar streetlight and power back-up applications.
- Rugged body to withstand high ambient day temperatures
- Broad operating temperature range of -40ºC to +60ºC
- Unmatched cycle life of ~ 3000 cycles at 70 per cent DOD
- Good high energy density of about 200Wh/kg
- Very low cell impedance
- Battery state of charge and health monitoring function
- Real-time communication of battery status through SMBus
- Total protection against over-voltage, under-voltage, over current and short circuits
Product: Solar tubular battery
Luminous offers C10 rated deep cycle solar batteries specially designed for longer back-up. They come in a wide range of capacities, starting from 20Ah to 200Ah with three and five-year warranties.
- C10 rating
- Deep cycle design for longer backup
- Tubular/tall tubular flooded battery for long life, available with three and five-year warranties
- Ah efficiency of > 90 per cent
Product: Solar batteries
Oxen Batteries provides a suite of advanced and reliable power protection and backup products including online UPS systems, sine wave inverters, servo controlled voltage stabilisers and solar power products for mission-critical telecommunication applications and sensitive equipment in server and network rooms.
- Extremely high purity, corrosion-resistant proprietary Spine alloy ensures longer life
- Extremely superfine void-free grain structure ensures corrosion resistance and high operational life
- Extra-strong, flexible oxidation-resistant gauntlet for higher performance and extremely long cycle life
- Highly puncture-resistant DARAMIC-USA separator minimises the possibility of internal short circuits
- Equally spread positive active material for better functioning and very low top-up
- Extra-strong, flexible, oxidation-resistant gauntlet
- Design-cycle life of over 1250 cycles at 80 per cent depth of discharge (DOD)