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Subject Maintenance of Flooded Lead Acid Batteries (E.g. Trojan batteries)
Author Sascha Deri
–When should I water my batteries?
Water is lost during charging. Therefore, the best time to water your batteries is always at the end of the charge cycle.

–How often should I water my batteries? How often you use your batteries will determine the frequency of watering. For example, the weekend fisherman may find he only needs to water the batteries in his boat once a month. While a maintenance supervisor for a golf course might need to service the batteries in their golf cars every week. Also using batteries in a hot climate may require more frequent watering. It is best to check your new batteries regularly as this will give you a good feel for how often your application will require battery watering. WARNING: A brand new battery may have a low electrolyte level. Charge the battery first and then add water if needed. Adding water to a battery before charging may result in overflow of the electrolyte.

–What is the proper electrolyte level?
Liquid levels should be 1/8 inch below the bottom of the vent well (the plastic tube that extends into the battery). The electrolyte level should not drop below the top of the plates.

–Do you ever add acid to a battery?
Under normal operating conditions, you never need to add acid. Only distilled, deionized or approved water should be added to achieve the recommended levels mentioned above. When a battery is shipped in a dry state or accidental spillage occurs, electrolyte should be added to the battery. Once filled, a battery should only need periodic water addition.

–Can batteries freeze?
In a partially discharged state, the electrolyte in a lead acid battery may freeze. At a 40% state of charge, electrolyte will freeze if the temperature reaches approximately ­16.0oF. The freezing temperature of the electrolyte in a fully charged battery is -92.0oF.

–What is the proper torque value for my battery connections?
You should always check with the dealer where you purchased your batteries or the manufacturer for the recommended torque values. A good rule of thumb, however, is to initially torque the hardware connection to 70 inch-pounds and re-torque annually, or as needed, to 65 inch-pounds.

–What is the specific gravity of a fully charged battery?
A hydrometer reading of 1.277 or greater indicates full charge for Trojan batteries. This value is based upon a specified temperature of 77 to 80oF. For temperature correction values, see battery maintenance or temperature.

–What are common mistakes made by lead acid battery owners? Undercharging: Generally caused by not allowing the charger to restore the battery to full state of charge after use. Continually operating the battery in a partial state of charge, or storing the battery in a discharged state results in the formation of lead sulfate compounds on the plates. This condition is known as sulfation. Both of these conditions reduce the battery's performance and may cause premature battery failure. Undercharging will also cause stratification. Overcharging: Continuous charging causes accelerated corrosion of the positive plates, excessive water consumption, and in some cases, damaging temperatures within a lead acid battery. Deep cycle batteries should be charged after each discharge of more than 50% of the batteries rated capacity, and/or after prolonged storage of 30 days or more.
Under-watering: In deep cycle, lead acid batteries water is lost during the charging process. If the electrolyte level drops below the tops of the plates, irreparable damage may occur. Water levels should be checked and maintained routinely.
Over-watering: Excessive watering of a battery results in additional dilution of the electrolyte, resulting in reduced battery performance. Additionally, watering the battery before charging may result in electrolyte overflow and unnecessary additional maintenance.

–Can I reduce my maintenance by not gassing or (bubbling) my batteries?
You will reduce the frequency of watering, but will cause a condition known as stratification, which results in poor performance and reduced battery life.

–How can I tell if a battery is bad?
The first indication of a battery problem is reduced performance. To determine if the battery is experiencing a problem, isolate the battery from all electrical loads and the charging source. Allow each battery in the system to stand on open-circuit for about one hour. Measure the voltage of each battery. If the battery voltage spread exceeds .15 volts for a 6 volt battery, or .30 volts for a 12 volt battery, a problem is indicated. Battery voltage alone does not confirm a problem. When the voltage spread indicates a problem, confirmation is accomplished by taking electrolyte specific gravity readings using a hydrometer. If the specific gravity readings show a spread greater than .030 (30 points), corrective action should be taken. The appropriate corrective action is to give the batteries an equalization charge.
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