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Knowledge Base: Glossary of Battery and Charger Terms and Definitions.
Example: Forklift Battery Watering System
Automatic Watering System
| Filler is Easily
Accessible | 5gal.
Reservoir | Water Level Indicator
The five most common reasons for Premature Battery Failure:
1. Low water levels
· From our experience, this is the number one cause of battery failure.
· Charging batteries that are as little as 1” low on water can cause damage to the entire battery that can never be repaired. It dries and burns the uppermost portion of the “plates”, causing high resistance that is permanent, and effectively isolates the portion that remained submerged.
· Even when the proper water levels are restored, the damaged portion continues to cause high resistance and the battery runs much hotter from that point forward, causing accelerated water loss and further plate damage due to overheating.
2. Over Charging and Opportunity Charging
· Industrial batteries are typically designed to last at least 1,500 charge cycles, over a five to fifteen year period. Each time you charge a battery, regardless of how long, it constitutes one cycle.
· Consistently charging a battery twice per day, during lunch breaks for example, is known as Opportunity Charging, and reduces the useful life of a battery by 50%.
· The additional heat generated by opportunity charging a battery usually reduces the run time equal or greater in proportion to the amount of charge it actually received, making the practice completely ineffective and costly.
· Routinely charging the battery before it is 80% discharged is another common form of over charging. For example, if you only use the battery a few hours a day, it’s best to use it until it is truly in need of charging before actually plugging it in. Remember, each charge constitutes one cycle, so try not to charge unnecessarily.
3. Over watering
· Commonly occurs as a reaction to low water levels, but is a major problem unto itself.
· Flushes the electrolyte from the cells and gradually dilutes the acid to the point that the battery can no longer function properly. In many cases this can be remedied sending the battery out to have the acid adjusted, but the battery’s life will still be shortened somewhat.
· Causes tray corrosion (listed below).
4. Failing to Equalize Charge
· Batteries should receive an Equalize Charge once every 10 cycles.
· Almost all chargers are equipped with an Equalize feature. On older chargers, this setting is usually referred to as Weekend or Weekly charge.
· Selecting this setting adds 3 additional hours to a normal charge, ensuring all of the cells in the battery reach full charge, and the allowing extra time for the electrolyte to mix during the Gassing Stage.
· Failure to equalize causes reduced battery run time and eventual failure, due to Sulfation, Stratification, and an imbalanced capacity between the cells.
· Batteries should be rinsed or washed at least once per year to prevent corrosion.
· Even when the proper water levels are consistently maintained, sulfuric acid vapors escape during charge. These vapors leave an oily sulfuric acid residue on the top of the battery around the vent caps. Over time, the water in the residue evaporates leaving full strength, concentrated acid that is much more concentrated than the diluted acid inside the battery.
· The concentrated acid is very conductive. As it gradually accumulates and spreads out, it eventually makes contact between the intercell connectors across the top of the battery. This results in shorting between the cells, causing the battery to self-discharge, and additional heat during charge and use.
· Even though battery trays have a baked on powder coat finish, they will easily corrode if the residue is not rinsed off. The corrosion will become progressively worse until it is either removed, or it destroys the battery.
CABLE CORROSION – REPAIRABLE: This is a commonly overlooked problem which causes reduced run time and all of the classic symptoms of a bad battery or cell. Many times this is the only problem, and replacing the corroded cable increases run time dramatically.
· CAUSE: If the battery is not rinsed periodically, acid penetrates the seal between the cable head and the insulation and begins to oxidize and corrode the copper conductors. The cable gradually swells over time as the copper breaks down, deteriorating the connection gradually until the battery no longer accepts a charge.
Examples of Battery Cable Corrosion: Swollen near terminal, copper is replaced by blue corrosion.
Positive Plate Growth – NOT REPAIRABLE: The true sign that a battery has reached the end of its useful life, and is in need of replacement. Typically begins to occur after 5 years. As batteries age, the positive plates begin to soften and expand in size. This causes internal pressure inside the battery cells. Most manufacturers now use floating bushings on the positive cell posts to allow for this gradual expansion and reduce stress on the cells internal components. Eventually, as the battery reaches the end of it’s normal useful life, the internal pressure is great enough to push the positive posts well beyond normal tolerances and can begin to distort the cell covers and vent wells. Positive plate growth is normal and should be considered as a wear indicator. If your battery is no longer holding a charge and shows signs of plate growth, it should be replaced, not repaired.
· Positive plate growth typically occurs after 5 years or 1,500 cycles. If it occurs in less than 5 years, it is most likely due to opportunity charging or over charging, which should be addressed when replacing the battery.
· This condition usually affects the Positive posts only, and will give an uneven, slanted appearance when viewed from the side, looking across the top of the battery.
Examples of Positive Plate Growth:
· SHORT RUN TIME: Progressively shorter run times could be caused by a malfunctioning battery OR charger. It is best to have both checked if you begin to experience shortened run time or suspect a problem.
· EQUALIZE CHARGE: Industrial batteries must receive an equalize charge at least once per month, or permanent damage will result. Never equalize more than once every 5th charge cycle, or damage will result. Reason: Selecting equalize mode on your charger adds 3 additional hours of charge time to that charge cycle, ensuring all of the cells reach 100% charge. Equalizing too often or too little will shorten battery life.
· WHEN TO ADD WATER, AND HOW MUCH TO ADD: Water can be added before or after charging. Add just enough water to cover the perforated element protector (visible at the bottom of the vent well). Never overfill. Reason: The water level rises up to one inch during the last (3) hours of recharge due to “gassing”. The visible water level before charging is always lower than after charging. Any excess water will simply overflow and cause corrosion and damage your lift truck. See “Proper Battery Care” for more information.
· NEVER ALLOW BATTER WATER TO RUN LOW OR DRY: Water should be added every 5 to 10 charges or permanent damage will result.
· WHAT KIND OF WATER TO USE: In general, normal city water will suffice, but if you have any doubts about purity of the local water supply, A) contact the GB battery supplier in your area B) get a chemical analysis of the water C) use distilled water.
· ADDING ACID: Never add sulfuric acid to a battery. If an acid spillage occurs, contact the GB battery supplier in your area.
· OVER DISCHARGING: Never over discharge batteries. More is not necessarily better when it comes to recharging batteries. Most battery manufacturers warrant their batteries for up to 1,500 cycles of charge and discharge provided, among other things, that the battery is never discharged beyond 80%. This normally coincides with an eight-hour shift. Trucks fitted with extra equipment such as clamps, high speed lifts, etc. will need a higher capacity battery to ensure the battery is not discharged beyond 80%. Lift truck interrupts are available to detect the correct discharge level and are recommended by battery manufacturers as a means of ensuring batteries are not over discharged. The best way to ensure batteries are not being overcharged is to periodically (once a month) check the temperature of the center cell on a battery at the end of regular charge. If the temperature of the electrolyte is more than 36° F above the ambient temperature, call your battery technician— there is a problem.
· AVOIDING SPARKS: Batteries produce and store hydrogen gas, which is highly explosive. Never weld near a battery. Never place metal objects on batteries. Such objects can cause a short circuit between adjacent cells and result in possible injury to those close to the battery. Similarly, people charged with caring for or operating batteries should not wear any metal jewelry.
· UNDER-SIZED CHARGERS: A charger that is more the 100AH less than the your battery’s rated capacity. Will result in an undercharged battery with significant reduction in operating life. Your local GB vendor has all the information to ensure the battery and chargers are precisely matched.
· OVER-SIZED CHARGERS: A charger that is over 100AH more than your battery’s rated capacity. Can overcharge and overheat your battery, reducing the operating life of your battery.
· WHEN TO REPLACE A BATTERY: Repair or replace batteries when capacity that has fallen below 80% of its rated capacity. Continuing to operate a bad battery can damage a truck's electric motor and electronics. Failing batteries also require recharging more frequently, wasting hundreds or thousands of dollars in energy per year, depending on the size of your fleet.
· RECORD KEEPING: We recommend that each forklift, battery and charger in your fleet be given a unique number for easy identification and tracking purposes. Keep regular records on the maintenance of batteries. For instance, keep a log of ever time a battery is watered and equalize charged, or at minimum, each time an operator complains of short run time and whenever cells or cables are replaced. These records will be invaluable when it comes to predicting when battery replacement will be necessary.
Example, 18-125-13: 13 – 1 = 12, / 2 = 6 x 125 = 750AH
Example, battery model 18-125-13, 36V / 750AH: 750 x 36 = 27,000 / 1000 = 27 x .97 = 26.19KWH.
· STATE OF CHARGE: Typical no-load voltages vs. state of charge:
Sample voltages are for a 12-volt / 6 cell battery system (figured at 10.5 volts = fully discharged, and 77 degrees F). For a 24-volt battery multiply by 2, for a 36-volt battery multiply by 3, 48-volt battery multiply by 4. VPC is the volts per individual cell - if you measure more than a .2 volt difference between each cell, you need to equalize, or the battery is beginning to go bad, or it could be sulfated. These voltages are for batteries that have been at rest for 3 hours or more. Batteries that are being charged will be higher - the voltages while charging will not tell you anything, you have to let the battery sit for approx. 3hrs. For longest life, batteries should stay in the green zone. Occasional dips into the yellow are not harmful, but continual discharges (or “cycles”) to those levels will shorten battery life considerably. It is important to realize that voltage measurements are only approximate. Note the large voltage drop in the last 10%.
How are batteries rated and what do the ratings mean in battery selection?
Manufacturers use different discharge periods to yield an different Amp-Hr. Rating for the same capacity batteries, therefore, the Amp-Hr. Rating has little significance unless qualified by the number of hours the battery is discharged. For this reason Amp-Hour Ratings are only a general method of evaluating a battery's capacity for selection purposes. The quality of internal components and technical construction within the battery will generate different desired characteristics without effecting its Amp-Hour Rating. For instance, there are 150 Amp-Hour batteries that will not support an electrical load overnight and if called upon to do so repetitively, will fail early in their life. Conversely, there are 150 Amp-Hour batteries that will operate an electrical load for several days before needing recharging and will do so for years. The following ratings must be examined in order to evaluate and select the proper battery for a specific application: COLD CRANKING AMPERAGE and RESERVE CAPACITY are ratings used by the industry to simplify battery selection.
How does the Cold Cranking Amperage rating help me select a battery?
3) RESERVE CAPACITY
What does the Reserve Capacity rating mean and how does it apply to deep cycle batteries?
For instance, GB uses thicker lead grids (the plate's skeletal structure) to support additional positive plate oxides which are compressed into a denser form in order to add battery reactive material for greater Reserve Capacity and Cycling Performance. In addition, these plates are separated by indestructible separators. These mats hold the active oxides tightly in place during the cubical plate expansion, which occurs during deep discharging, instead of allowing the oxides to shed off and precipitate to the bottom of the battery. Construction materials such as those raise the Reserve Capacity of a battery and increase the battery's Cycle Life.
What is battery cycle life?
What is the difference between deep cycle batteries and starting batteries?
Deep cycle batteries can be used in any application and exhibit a long service life, while cranking batteries are limited to starting applications only. Cranking batteries exhibit poor service life in cycling applications.
6) INCREASING CAPACITY THROUGH SERIES AND PARALLEL CONNECTIONS
What is the difference between series battery connections and parallel battery connections and how do they increase battery capacity and voltage?
In the PARALLEL CONNECTION, batteries of like voltages and capacities are connected to increase the capacity of the bank. The positive terminals of all batteries are connected together, or to a common conductor, and all negative terminals are connected in the same manner. The final voltage remains unchanged while the capacity of the bank is the sum of the capacities of the individual batteries of this connection. Amp-Hours Cranking Performance and Reserve Capacity increases while Voltage does not.
Does overcharging damage batteries?
Does over discharging damage batteries?
CHARGING Alternators and float battery chargers including regulated photo voltaic chargers have automatic controls which taper the charge rate as the batteries come up in charge. It should be noted that a decrease to a few amperes while charging does not mean that the batteries have been fully charged. Battery chargers are of three types. There is the manual type, the trickle type, and the automatic switcher type.
9) BATTERY ELECTROCHEMISTRY EVALUATION
How can I evaluate the health and charge state of a battery?
100% Charged = 1.285 - 1.290 Sp. Gr.
75% Charged = 1.240 - 1.245 Sp. Gr.
50% Charged = 1.195 - 1.200 Sp. Gr.
25% Charged = 1.150 - 1.155 Sp. Gr.
0% Charged = 1.115 - 1.120 Sp. Gr.
Temperature compensation of hydrometric readings is usually unnecessary unless the battery is extremely hot or cold, however, after hard charging or discharging, you may want to add or subtract points of Specific Gravity based on the table.
Do not apply hydrometer color-coding to readings taken from deep cycle batteries. These red-white-green markings are for "hot" automotive battery types. Also, hydrometer readings taken immediately after water is added to a cell is inaccurate. The water must be thoroughly mixed with the underlying electrolyte by charging, before hydrometer readings are reliable. In addition, do not assume a deep cycle battery will not take a charge because you have been charging it for a while and the float will not rise. If the battery has been fully discharged or partially sulfated it will require considerable charging or equalization before recovering. As electrolyte levels are reduced in the battery, it is important to add water to each cell. Note that only the water portion of the electrolyte evaporates, therefore, it is not necessary to add acid to a battery during maintenance. In fact, the addition of acid to an active battery will reduce its capacity and shorten its remaining life. Water should be added to cells after charging the battery. This will eliminate spillage due to expansion of electrolyte upon charging. Generally speaking, any water that is safe to drink is safe to use in a battery. Do not use water of a known high mineral content or stored in metallic containers. It is the metal impurities in the water that lower the performance of the battery. Distilled water guarantees purity.
If you suspect your charger fails to shut off or your battery
overheats for any reason, discontinue use immediately and call for service.
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