Bob F Posted February 7, 2009 Report Share Posted February 7, 2009 The most common way of testing the health of a battery cell is to measure the specific gravity of the electrolyte using a hydrometer. What is the approx specific gravity of a healthy battery cell? 1.000 1.190 1.225 1.270 1.835 Quote Link to comment Share on other sites More sharing options...
Bob F Posted February 7, 2009 Author Report Share Posted February 7, 2009 Stay with me on this one, cus it leads to a way of determining whether you should recharge the battery or buy a new one. This is the penultimate question on batteries. BF Quote Link to comment Share on other sites More sharing options...
Bob F Posted February 9, 2009 Author Report Share Posted February 9, 2009 The correct answer is 1.270, so congratulations to those that researched the answer. ~1.270 is the Specific Gravity for a fully charged cell. 1.835 is the SG for pure Sulphuric Acid. 1.000 is the SG for pure water. To verify if a battery is worth keeping, check the SG of each cell. If one or more cells differ by more than 50 points (0.050) the battery is defective and should be replaced. If the SG of all of the cells are over 1.225 and the variation between cells is less than 50 points (0.050), the battery can be tested on full load to more thoroughly check that it can handle a real load. To test the battery under load, first check it without a load. Simply turn the engine on (with all auxilliaries turned off) and put a Multimeter across the two terminals of the battery. You should be ~14.4 volts. Next turn on all the auxilliaries that draw the most current (like windscreen wipers, flood lights, radar, pumps, etc) with the engine still running. Now check the voltage across the terminals of the battery again. If the voltage is between 12.2 volts and 14.4 volts the battery is ok. cheers BF Quote Link to comment Share on other sites More sharing options...
great white Posted February 9, 2009 Report Share Posted February 9, 2009 so congratulations to those that researched the answer. I think congratulations are due for you for researching the questions and answers Education is always time well spent Quote Link to comment Share on other sites More sharing options...
Bob F Posted February 9, 2009 Author Report Share Posted February 9, 2009 Quote Link to comment Share on other sites More sharing options...
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