Connect with us

Hi, what are you looking for?

Know-How

Why are Tubular Lead Acid Batteries the most viable Energy Storage devices?

10 kw inverter price in pakistan

A discharge/charge cycle is commonly understood as the full discharge of a charged battery with subsequent recharge, but this is not always the case. Batteries are seldom fully discharged, and manufacturers often use the 80 percent depth-of-discharge (DoD) formula to rate a battery. This means that only 80 percent of the available energy is delivered and 20 percent remains in reserve. Cycling a battery at less than full discharge increases service life, and manufacturers argue that this is closer to a field representation than a full cycle because batteries are commonly recharged with some spare capacity left.

Related: Know about other types of Lead Acid batteries including Valve Regulated Lead Acid Battery (VRLA) i. AGM ii. GEL.  

A crank battery has a large surface area with thin plates for quick surface chemical reactions and it is designed for cranking application and so the performance parameter is the cold cranking amperes a typical crank battery offers and not the backup. In contrast ‘deep discharge’ battery has thicker plates with a less exposed surface that forces the chemical reactions to move into the plates deeper during a discharge.

No alt text provided for this image

The main trade-off in battery development is between power and energy: batteries can be either high-power or high-energy, but not both. 

Having said this, Tubular Lead Acid battery (OPzS) is undisputedly the most economical deep discharge battery and can be used for efficient backup. 

There are some performance-related factors one should consider before choosing their battery:

  1. The Open-circuit Voltage (quiescent) at full charge
  2. The Open-circuit Voltage at full discharge
  3. Loaded Voltage at full discharge
  4. Equalization charging voltage
  5. Discharge rate curves (C1, C3, C5 and C10)
  6. Duty cycles for 20%, 35%, 50%, 80% DOD
  7. Self-discharge curve

Calculations:

A C-rate is a measure of the rate at which a battery is discharged relative to its maximum capacity. A 1C rate means that the discharge current will discharge the entire battery in 1 hour. For a battery with a capacity of 100 Amp-hrs, this equates to a discharge current of 100 Amps. A 5C rate for this battery would be 500 Amps, and a C/2 rate would be 50 Amps. A 10C rate battery would be able to discharge 1000 Amps without doing damage to the battery. 

There are some very critical certification-related aspects that need to be checked:

  1. IEC Standard PV solution compliance 60896 (TC 21/TC 82)
  2. IEC Standard compliance 60896-11
  3. IEC Standard compliance 60896-2
  4. IEC Standard Cycling test 61427
  5. IEC 61147/ NF C58-510
  6. IEEE 535 Lead Selenium aging result for Tubular Batteries

Conclusion:

The purpose of a battery is to store energy and release it at the desired time. Properly manufactured stationary batteries of tubular design are an excellent candidate for long-duration duty cycles of two (2) to one-hundred (100) hours of standby application as well as cyclical requirements. 

Advertisement. Scroll to continue reading.

Glossary: 

Duty Cycle: The complete charge and discharge of a battery at a certain DOD constitute one complete duty cycle.

Note: In Pakistan, effectively the battery undergoes an average of 2 duty cycles a day, and therefore at a certain DOD, we can calculate the life expectancy in years of a battery by dividing the claimed duty cycles divided (by 2*365 days).

Depth of Discharge (DOD): Is the useful percentage window of discharge available between floating voltage and loaded voltage at discharge. 

Note: 100 Ah battery with nominal 10-hour discharge rate (C10) can ideally allow a drain of 20A in 1 hr at 20 percent DOD at 10-hour discharge rate.  

Click to comment

Leave a Reply

Your email address will not be published. Required fields are marked *

You May Also Like

Know-How

Background: Tubular batteries used in thousands of solar home solutions installed by M/S Rahimafrooz in Bangladesh show +11 years of normal life with precedents....

Know-How

Ever wondered if a single chamber could help render all these applications such as large-scale and commercial drying of flowers, fruits, vegetables, crops, grains,...

List

For many Pakistanis as well as other countries electricity used in the evening is significantly more expensive than the power that is utilized during...

Advertisement