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Battery Health Info

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Guys, I've been meaning to post this, so here it is. Source was from Interstate Batteries. Numbers reflect a 6 cell 12 volt lead-acid battery. Open Circuit Voltage VS. State of Charge 12.66V 100% 12.45V 75% 12.24V 50% 12.06V 25% 11.89V 0% To determine if the battery is experiencing a problem, turn off all electrical loads and the charging source. For an accurate reading, allow the fully charged battery to sit with no electrical loads applied for at least one hour. Connect a voltmeter to the positive and negative terminals and measure the terminal post voltage with no loads or chargers connected to the battery. Allowing it to sit longer (days/weeks)then measuring the OCV can show if the battery has an internal short or insulation problem (i.e. rapid self-discharge issue). ------------------------------------------------------------------- Specific Gravity VS. State of Charge 1.265 100% 1.225 75% 1.190 50% 1.155 25% 1.120 0% Check each individual battery cell. If the specific gravity varies more than .050 or "50 points" among the cells while the battery is at a 75% state of charge or above, then the battery is bad and should be replaced. The cells that have a specific gravity of 50 points less than the highest cell are bad cells. A hydrometer reading of 1.265 or greater at 80°F indicates a full charge for Interstate batteries. To determine the battery's state of charge, compare the hydrometer reading to the Specific Gravity Chart. To get the most accurate hydrometer reading, you should adjust your hydrometer reading according to the temperature. If the electrolyte temperature is ABOVE 80°F , ADD .004 (called "four points") to the hydrometer reading for each 10 degrees above 80°F. If the electrolyte temperature is BELOW 80°F, SUBTRACT four points from the hydrometer reading for each 10 degrees below 80°F. Tom(PK) --------------------------------------------------------------------------------

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Tom, That is good information. I just went through a simialer class for AC-DELCO. it covered most of the same stuff that can be very useful. One other thing that most people over look is to make sure that the battery terminals are clean and there are no other Green connections anywhere else.

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