Battery Tips

Discharged Batteries Do not leave batteries in a discharged state for more than a day or two. They will undergo a chemical process (sulfation) that can permanently damage the battery. As well, batteries self-discharge over a period of three to six months, so they should be recharged periodically even if they are not being used.

Electrolyte Level If your batteries are not the “maintenance- free” type, check the electrolyte level at least once a month. Excessive fluid loss is a sign of overcharging. Replenish the electrolyte using distilled water only.

Battery Connections Connections to battery posts must be made with permanent connectors that provide a reliable, low- resistance connection. Do not use alligator clips. Clean the connections regularly and prevent corrosion by using a protective spray coating or vaseline.

Battery State of Charge You can measure battery state of charge with a hydrometer or, more easily, with a voltmeter. Use a digital voltmeter than can display tenths or hundredths of a volt when measuring 10 to 30 volts. Make your measurements when the battery has not been charged or discharged for several hours. For a deep-cycle battery at 77º F (25º C), use the following table:

Battery Voltage State of Charge

12.7–13.0 100%

12.5–12.6 80%

12.3–12.4 60%

12.1–12.2 40%

11.9–12.0 20%

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