Battery Type
> SLI Battery: Starting, Lighting & Ignition Battery : Automotive Etc.
> Deep Cycle Battery: A deep-cycle battery is a lead-acid battery designed to be regularly deeply discharged using most of its capacity
Forklift, Golf Cart, Lift Etc
– VRLA Battery (SLA Battery) : Valve Regulated Lead Acid Battery [Sealed Lead Acid Battery]. Commonly known as a sealed battery or maintenance free battery. There are two primary types of VRLA batteries, GEL Type and AGM Type.
– GEL Type : Gel cells add silica dust to the electrolyte, forming a thick putty-like gel
– AGM Type : Absorbed Glass Matt forces fibreglass mesh between the battery plates with the same basic outcome
Battery Facts
> 12 Volt Battery has six cells: 2V X 6 cells =12V
> Each cell is 2.13 Volts: 2.13V x 6 cells = 12.78 Volts
> 12.78 V or higher = fill Charge
> Discharged Battery = 1.75 Volls per cell : – 1.7SV x 6 cells = 10.5 V (Low Voltage Cuto
– < 12.0 V = Dischared
How Battery Works
> Full Charged
>> Pos(+) ± Pbo2
>> NEG{-) = Pb
>> Elertrolyte = 2H2S04
> Fully Discharged
>. PGSl+| ± PbSO
>> NEG(-) = Pbso4
>> NEG(-) = Pbso4
>> Elertrolyte ± H2O
Why Batteries Fail?
> Overcharging – Corroded plates -Water loss (Gel or Separator dry-out)
> Underdlarging : – Sulfation & Corrosion
> Discharged Storage : – Sulfation, Corrosion & Hydration
> Over-Discharging
-P05 (+) Plate damage
>Abuse Dropped / cracked , Broken posts, High heat, Poor Quality controls of product
> Poor Maintenance: Lack of systematic power supply, maintenance, Lack of testing
How do batteries work?
>> When the two dissimilar metal plates are immersed in acid they create a voltage.
>> This voltage is created by the concentrating Negative Ions on the negative plates and Positive Ions on the positive plates.
>> As batteries discharge the acid is turned to water and the lead plates are turned into lead sulfate.
>> When both plates are turned to lead sulfate the battery is discharged or dead.
How many volts does one battery cell produce?
>> 1 cell 2 2.1 volts
>> How many cells in a 12 volt battery? = 6 cells
>> How many volts in a 12 volt battery ? = 12.6 Volts
>> How can you get 12.6 volts out of a bunch of 2.1 volt cells ? = wire them in series
What comes out of a battery?
>> What is power ? (Electrical POWER) = Watts : Volt X Amperes
>> How do you get more volt out of a battery ? = add more cells in series
>> How do diesel vehicles get 24 volt for starting ? = wiring 2-12 volt or 4-6 volt batteries in series
What happens as all the amps get used up?
>> The electolyte turns to water and … the lead and sponge lead plates turn to Lead sulfate and the acid will no longer strip electrons from the positive plates and add them to the negative plates.
The battery will go DEAD
- Starting Batteries>.> The function of the battery is to start the engine.
>> Then the generator will run all electrical loads.
>.> Some Recreational Vehicles use both a starting battery and a deep cycle battery.
>> The deep cycle battery is not hooked to the starter motor.
>> If you allow a starting battery to slowly go dead it will “SULFATE”.
>> This happens when lead sulfate [formed when a battery discharges) crystallizes on the surface of the lead plates.
>>This will not allow the battery to fully recharge.
>.> Sometimes a sulfated battery will not recharge at all. - Deepcycle Batteries>> Some RV and Marine batteries are different.
>> They are intended to operate smaller electrical loads (lights, 12 volt accessories, trolling motors etc.) for long periods of time without being recharged.
>> They are called Deep Cycle batteries as they can withstand many cycles of long slow discharging followed by long slow charging.
>> Rapid discharging (like the hundreds of amps pulled by a starter motor) will ruin a Deep Cycle battery… it will overheat the plates.
* Storing Baneries
>> When a battery is new the lead and acid will begin to react and it will slowly Discharge.
>> Any battery that sits unused for several months will slowly go dead and begin to sulfate.
>> This will ruin the battery.
>> All batteries be periodically redtarged.
>> New batteries, awaiting sale, are given a “trickle charge” on a regular schedule
How do I determine the battery state of charge?
>> Use a hydrometer and compensate for the temperature of the battery.
>> As a battery discharges the acid turns to water.
>> Acid is thicker and will float the hydrometer scale higher.
>> A fully charged battery cell has a “specific gravity” of 1.265 at 80 degrees
Hydrometer Testing
>> A colder battery wil measure higher as cold liquid is thicker. ‘
>> A cold battery may look charged actually be undercharged.
>> Check each cell If the lowest cell is .050 points lower than the highest cell the battery is defective.
>> If water has just been added to the battery it will give a false hydrometer reading
What if there are no removable vent caps?
>> Some batteries include a built in hydrometer.
>> This checks one cell only.
>> Indicates the battery is at least 75% charged when green (or not black/clear).
>> You can also test a battery state of charge with a volt meter
Testing the battery state of charge with a volt meter
>> 12.70 V = a fully charged battery
>> 12.40 V = 75% charged
>> 12.40 V = 75% charged
>> 12.10 V = 50% charged
>> 12.10 V = 50% charged
My battery reads 13.2 Volts… ls it overcharged?
>> Some recombinant battery maintain a slightly higher open circuit voltage.
>> Normal batteries will also register a surface charge.
>> This is not an accurate reading of e state of charge
I don’t have time for a slow charge! What’s wrong with quick charging?
>> Nothing IF YOU FOLLOW SAFETY PRECAUTIONS to protect the battery and the vehicle.
>> To protect vehicle computers from high voltage you should unhook the vehicle ground before turning on the charger.
How do I monitor the battery?
Check the voltage across the terminals with the charger on.
>> If it gets over 1 5 volts turn off the charger or siow the rate of charge.
Feel the case of the battery,
>> if it gets hot it is overcharging
>> all batteries will get warm,
>> practice to know hot from warm
Look. listen and smell for gassing.
>> If you see lots of bubbles through the battery case (white case) turn down the charger.
>> If you smell the gas, turn down the charger.
>> Leave the vent caps on.
>> Turn off and unplug the charger BEFORE removing the charging cables from the battery.
Load Testing or Battery Capacity Testing
>> It the battery recovered to 12.7 volts but dropped below 9.6 volts during the load test.
>> Recommend a new battery.
What do I do with the old, junk battery?
>> Batteries contain hazardous lead and other nasty things.
>> They are very harmful to the environment.
>> It is illegal to place them in the trash or landfill.
>> Any business that sells batteries… is legally obligated to recycle them.
This battery was only 3 years old, what caused it to fail?
>> Vibration Check hold down
>> Overcharging look for bulged case, low electrolyte voltage with engine running after battery is fully charged.
>> Discharged (sulfated) look for dirty battery case and corroded battery cable ends.
>> Recommend more frequent battery cleaning.
What causes Sulfation?
>> Check voltage drop across positive and negative battery cables during cranking should have less that 0.3 volts.
>> Check for parasitic draw.
>> Should have less than 50 milliamps
>> Check for low voltage with engine running after battery is fully charged.
>> Insure voltage stays up with all accessories turned on and engine running at 2,000 RPM.
>> Quiz customer on driving habits short trips will not allow battery to fully charge
Battery Characteristics and Types
Battery Components
Battery technology has not changed much in the last 100 years. The standard construction method involves flooding lead plates in sulfuric acid.
The chemical reaction between the positively charged lead plate and the negatively charged acid allows the battery to store and “give” electricity.
The thickness of the lead plate is closely related to the lifespan of the battery because of a factor called “Positive Grid Corrosion”.
The positive lead plate gradually wears away over time. Thicker plates are used in deep cycle batteries. This usually translates to a longer battery life.
Although plate thickness is not the only factor related to longer lifespan, it is the most critical variable.
Battery Lifespan
Most of the loss incurred in charging and discharging batteries is due to internal resistance, which is eventually wasted as heat. Efficiency ratios are
relatively high considering that most lead acid batteries are 85 to 95 percent efficient at storing the energy they receive. Deep cycle batteries used in
renewable energy applications are designed to provide many years of reliable performance with proper care and maintenance. Proper maintenance
and usage play a major role in battery lifespan. Toiling over your battery bank daily with complex gadgets and a gallon of distilled water, however,
is not necessary. The most common causes of premature battery failure include loss of electrolyte due to heat or overcharging, undercharging,
excessive vibration, freezing or extremely high temperatures, and using tap water among other factors.
Battery Charging Stages
There are three basic stages in charging a battery: bulk, absorption, and float. These terms signify different voltage and current variables involved in
each stage of charging.
* Bulk Charge : In the first stage of the process, current is sent to the batteries at the maximum safe rate, batteries will accept it until voltage is
brought up to nearly 80-90 percent full charge level. There are limits on the amount of current the battery andlor wiring can take.
* Absorption Charge: In the second stage, voltage peaks and stabilizes and current begins to taper off as internal resistance rises. The charge
controller puts out maximum voltage at this stage.
* Float Charge : This can also be referred to as trickle charging or a maintenance charge. In this stage, voltage is reduced to lower levels in order
to reduce gassing and prolong battery life. The main purpose of this stage is basically to maintain the battery’s charge in a controlled manner.
In Pulse Width Modulation lPWMl the charger sends small, short charging cycles or “pulses” when it senses small drops in voltage.
Depth of Discharge (DOD)
The Dep of Discharge (DOD) is used to describe how deep the battery is discharged. If the battery is too fully charged, it means the DOD of battery is )%. The Dep of Discharge (DOD) is used to describe how deep the battery is discharged. If the battery has delivered 30° of its energy, here are 70 energy reserved, the DOD of is battery is 30%. And if a battery is 100 empty, e DOD ofis battery is 100%. DOD alway Earn be beated as how much energy that the battery delivered.
Determining battery state of charge
There are a few ways to determine the state of charge on a battery, each with their own level of accuracy. As there is no direct method to measure a battery’s state of charge, there are numerous ways to go about it. One way to gauge a battery is by measuring its static voltage and comparing it to a standardized chart. This is the least accurate method, but it only involves an inexpensive digital meter. Another method of gauging the battery
involves measuring the density or specific gravity of the sulfuric acid electrolyte. This is the most accurate test, yet it is only applicable to the flooded types. This method involves measuring the cell’s electrolyte density with a battery hydrometer. Electrolyte density is lower when the battery is discharged and higher as the cells are charged. The battery’s chemical reactions affect the density of the electrolyte at a constant rate that is predictable enough to get a good indication ofthe cell’s state of charge. Using an amp-hour meter one can a so obtain an accurate indication of the battery’s state of charge. Amp-hour meters keep track of all power moving in and out of the battery by time, and the state of charge is determined by comparing flow rates.
Amp-Hour rating & Capacity
All deep cycle batteries are classified and rated in amp-hours. Amp-hours is the term used to describe a standardized rate of discharge measuring current relative to time. It is calculated by multiplying amps and hours. The generally accepted rating time period for most manufacturers is 20 hours. This means that the battery will provide the rated amperage for about 20 hours until it is down to 10.5 volts or completely dead. Some battery manufacturers will use 100 hours as the standard to make them look better, yet it can be useful in long-term backup calculations
Renewable Applications
There are three main types of batteries that are commonly used in renewable energy systems, each with their own advantages and disadvantages. Flooded or “wet” batteries are the most cost efficient and the most widely used batteries in photovoltaic applications. They require regular maintenance and need to be used in a vented location, and are extremely well suited for renewable energy applications. Sealed batteries come in two varieties, the gel cell and Absorbed Glass Mat (AGM) type. The gel cell uses a silica additive in its electrolyte solution that causes it to stiffen or gel, eliminating some of the issues with venting and spillage. The Absorbed Glass Mat construction method suspends the electrolyte in close proximity with the plate’s active material. These batteries are sealed, requiring virtually no maintenance. They are more suitable for remote applications where regular maintenance is difficult, or enclosed locations where venting is an issue.
a) Flooded Lead Add (FLA)
Flooded lead acid batteries are the most commonly used batteries, and have the longest track record in solar electric systems. They usually have the longest life and the lowest cost per amp-hour of any of the other choices. The downside is that they do require regular maintenance in the form of watering, equalizing charges and keeping the terminals clean. These cells are often referred to as “wet” cells, and they come in
two varieties: the serviceable, and the maintenance-free type (which means they are designed to die as soon as the warranty runs out). The serviceable wet cells come with removable caps, and are the smarter choice, as they allow you to check their status with a hydrometer.
b) Gelled Electrolyte Sealed lead Acid (GEL)
Gel sealed batteries use silica to stiffen or “gel” the electrolyte solution, greatly reducing the gasses, and volatility of the cell. Since all matter expands and contracts with heat, batteries are not truly sealed, but are “valve regulated This means that a tiny valve maintains slight positive pressure. AGM batteries are slowly phasing out gel technology, but there still are many applications for the gel cells. The recharge voltage for
charging Gel cells are usually lower than the other styles of lead acid batteries, and should be charged at a slower rate. When they are charged charging Gel cells are usually lower than the other styles of lead acid batteries, and should be charged at a slower rate. When they are charged too fast, gas pockets will form on the plates and force the gelled electrolyte away from the plate, decreasing the capacity until the gas finds its
way to the top of the battery and recombines with me electrolyte.
c) Sealed Absorbed Glass Mat (AGM)
Absorbed Glass Mat {AGM} is a class of valve-regulated lead acid battery (VLRAl in which the electrolyte is held in glass mats as opposed to freely flooding the plates. This is achieved by weaving very thin glass fibers into a mat to increase surface area enough to hold sufficient electrolyte for the lifetime of the cell. The advantages to using the AGM batteries are many, yet these batteries are typically twice the cost of their flooded-cell counterpart. On the plus side, these cells can hold roughly 1.5 times the amp hour capacity of a similar size flooded battery their flooded-cell counterpart. On the plus side, these cells can hold roughly 1.5 times the amp hour capacity of a similar size flooded battery due to their higher power density. Another factor that improves their efficiency is the higher lead purity used in AGM cells. Because of their sandwich construction, each plate no longer has to support its own weight. Their low internal resistance allows them to be charged and discharged much faster than other types. AGM cells function well in colder temperatures and are highly resistant to vibration. There are many advantages to using the AGM cells over their flooded counterpart that are beyond the scope of this article.
Maintenance & Monitoring
Proper maintenance and monitoring will greatly extend the life of your batteries. Flooded batteries need to be checked regularly to make sure electrolyte levels are full. The chemical reaction releases gases, as water molecules are split into hydrogen and oxygen. This, in turn, consumes water and creates the need to replace it regularly. Only distilled water should ever be used in batteries, and you should never add any kind of acid solution. The connections from battery to battery and to the charging and load circuits should always be kept clean and free of corrosion. Corrosion is created upon charging. when a slight acid mist forms as the electrolyte bubbles. Corrosion buildup will create a good deal of e electrical resistance, eventually contributing to a shortened battery life and malfunctions. A good way to keep up on the terminals is to regularly clean them with a baking soda solution
Future Trends
Companies world-wide are quickly adjusting to the increased global market for solar systems by developing batteries that are better suited for photovoltaic systems. At some distant point in the future, it is likely that lead-acid batteries will become extinct, as newer technologies in lithium ion and Nickel metal hydride continue to evolve. Because lead-acid batteries are under the hood of virtually every car, advancements in
lead-acid technology, however are still being made. New developments in lead-acid technology usually originate in the auto industry.
Efficiency ratings are constantly going up, as new sensors and improved materials are helping batteries achieve longer lifespan
Battery Repair 