Deep cycle battery(solar battery)

Batteries are collections of cells that produce electricity through electrochemical reactions. Cells can be configured into batteries of many different shapes and sizes.A battery cell is the basic unit in a battery that stores electrical energy in chemical bonds and delivers this energy through chemical reactions. Battery designs can vary by type and manufacturer, but many share the same basic components and store electricity using similar electrochemical reactions.

Batteries

• Although chemical reactions in the various battery chemistries are different, and some are very complex, the basic principle is always the same. The battery contains negative (anode) and positive (cathode) plates separated by a gel or liquid.

• The chemical reaction in the battery causes negative electrons to be stripped from the cathode and migrate towards the anode, giving the cathode a positive charge and the anode a negative charge.

• If an external circuit of conductive material (usually copper wire) joins the two plates, the electrons will flow from the anode to the cathode as they attempt to restore the balance.

Battery basics

LoadElectron flow

Current flow

Lead acid battery

The lead (Pb)–acid battery was invented in 1859 by French physicist Gaston Planté and is the oldest type of rechargeable batteryAs they are inexpensive compared to newer technologies, lead-acid batteries are widely used even when surge current is not important and other designs could provide higher energy densities.Large-format lead-acid designs are widely used for storage in backup power supplies in cell phone towers, high-availability settings like hospitals, and stand-alone power systems.

For these roles, modified versions of the standard cell may be used to improve storage times and reduce maintenance requirements. • Gel-cells• Absorbed glass-mat (AGM) batteries are common in these roles,

collectively known as VRLA (valve-regulated lead-acid) batteries.This two type of batteries are used a lot in solar panel & wind turbine project.

Lead acid battery

Lead acid battery

VIDEO

Deep Cycle vs Shallow Cycle

Deep• Deep cycle batteries

can be repeatedly discharged to 80%

and recharged without damaging

them• Recommended for

use with solar

Shallow• Occurs when the top

20% or less of the batteries energy is

discharged and then recharged

• Shallow cycle batteries not

recommended for solar use

Lead acid batteryA deep-cycle battery is a lead-acid battery designed to be regularly deeply discharged using most of its capacity. • In contrast, starter batteries (e.g. most automotive

batteries) are designed to deliver short, high-current bursts for cranking the engine, thus frequently discharging only a small part of their capacity. While a deep-cycle battery can be used as a starting battery, the lower "cranking amps" imply that an oversized battery may be required.

• A deep-cycle battery is designed to discharge between 45% and 75% of its capacity, depending on the manufacturer and the construction of the battery. Although these batteries can be cycled down to 20% charge, the best lifespan vs cost method is to keep the average cycle at about 45% discharge. There is a direct correlation between the depth of discharge of the battery, and the number of charge and discharge cycles it can perform.

Lead acid batteryThe deep-cycle battery is designed for maximum energy storage capacity and high cycle count (long life), and are rated in Amp/Hours. This is achieved by installing thick lead plates with limited surface areaTypical applications are boats, golf carts, wheelchairs, solar applications, RVs, and Uninterruptible Power Supplies (UPS).

Flooded cell lead acid battery

Gel type lead acid battery

AGM type lead acid battery

Lead acid batteryThe oldest types of lead acid batteries are flooded cell types. These have been around for decades and evolved from wooden box models into the plastic valve regulated models on the market today. The electrolyte in these batteries is liquid sulfuric acid solution. This stuff is pretty corrosive. VRLA flooded batteries generate and vent dangerous explosive gases through their valve regulation and must be vented to the outside world. These batteries also acid "mist" during charging and discharging. This leads to the corrosion of their terminals, and often-acid damage to surrounding surfaces. (look at your car battery for an example) VRLA Flooded batteries must be installed upright, can leak that acid, and require regular watering. Should they fail to be watered, they will not perform to spec

Lead acid batteryThe Gel battery introduction and widespread adoption was due to their increased efficiency and designed safety features. Their acid is immobilized by adding "fumed" silica to the sulfuric acid solution and then sealing the battery. They internally recombine most of the gases (hydrogen and oxygen) generated during charging and are maintenance free due to thisGel electrolyte battery designs are generally quite old and few engineering options are left to improve them. Gel electrolyte is highly viscous and during charge and discharge the gel can develop voids (pockets) or cracks when the amperage is increased. These pockets impede acid flow and result in the loss of battery capacity. Also the gelled mixture can liquefy upon charge due to the shearing action of gassing (this property is called "thixotropic"). After termination of charge, it can take an hour for the acid to gel again. During this time liquid is moving and the battery can leak if any opening has developed. Last, gel batteries may store hydrogen gas that has not recombined. When overcharging causes a gel battery's vent caps to open, explosive gasses may be vented into the battery compartment. This vented hydrogen has caused a number of "fast failures" or battery explosions.

Lead acid batteryThe latest and most advanced battery technology is Advanced AGM VRSLAB batteries (Advanced Glass Mat, Valve Regulated Sealed Lead Acid Batteries), which were developed to provide increased safety, efficiency, and durability over all existing battery types. In Advanced AGM batteries the acid is absorbed into a very fine glass mat and held in place by capillary action. This construction technique, in coordination with double wall design, and sealing has many advantages. There is never a way to make the acid free to slosh around. This allows for installation at any angle, and has lead to DOT exemption for USPS, UPS, and Fedex (department of transportation).By keeping the "moist" with electrolyte, gas recombination is more efficient (99% AGM). This leads to fewer incidents of exploding batteries than either of the 2 types above. 

Lead acid batterySince the AGM material has an extremely low electrical resistance, the battery delivers much higher power and efficiency than other battery types. Since the AGM material has an extremely low electrical resistance it can crank more amps in and out without cost to life. AGM batteries are rated at 100% their capacity for charging and discharging amperage. (compared with roughly 35% for gel and flooded models) Less acid means a lighter battery Advanced AGM batteries offer exceptional life cycles by far better than either gel or flooded batteries. This leads to longer battery life and increases your ROI

Deep cycle battery

Deep cycle battery

Connecting battery

VIDEO

This diagram shows a combination series and parallel circuit to increase both the battery current and voltage level at the same time.

Assume this time we are using 12 volt batteries. The left to right series connection add the two 12 volt batteries to make 24 volts.

And, since we did this 3 times and then connected each group of 2 (now 24 volts) in parallel we end up with one very large 24 volt battery.

It has twice the voltage of a single 12 volt battery wired in series and 3 times the current or power because all 3 groups are wired in parallel.

Connecting battery

• Discharge rate of battery is expressed as a ratio of the nominal battery capacity to the discharge time in hours.

• For example, a 5 A discharge for a nominal 100 Ah battery would be a C/20 discharge rate.

• The designation C/20 indicates that 1/20th of the rated capacity is discharged per hour or that the battery will be completely discharged after 20 hr.

• Capacity is directly affected by the rate of discharge.

Discharge rate of battery

Then the power required per-day = 11 x 40 watts = 440 watts

If the battery capacity = 40 AH 12V battery quantity = 150/40 = 3.75 we choose 4 nos parallel

If the battery capacity = 40 AH 24V battery quantity = 80/40 = 2 we choose 2 nos parallel

If written as 250 AH, 100-hr rate It means, we can use the battery for 100 hrs w/ 2.5 amps/hr load