Thursday, May 13, 2010

Battery Test & Charging Procedures


When using an Ac Delco filler cap battery start with a visual inspection. If there are any physical damage present replace the battery. If there are no apparent damage to the battery then proceed to check on its electrolyte levels.

Physical damages to look out for:

  • Cracked or broken
  • Severe corrosion
  • Cracked or Broken container

Fluid should be above top of plates in all cells. But make sure no spark or open flame is near while the caps are off. If this is so then proceed to Specific gravity check.

If the fluid levels are below the plates then add water, replace vent caps, and charge the battery for 15 min. at 15-25 amps to mix electrolyte. and then proceed to Specific gravity check.


Hydrometer reading of all cells should be at least 1.224 and show less than 0.050 between high and low, at electrolyte temperature of 80*F

if there is more then a 0.050 difference replace the battery. Less then that, and some batteries may read less then 1.225: recharge battery. Replace vent caps, use rate less then 50 amps, until cells measure proper specific gravity. If charging does not adjust the specific gravity to the proper level replace the battery.


As with the Filler cap battery when dealing with a Maintenance free battery it is important to start with a visual inspection. If there is any physical damage present it is a sure indicator that the battery should be replaced.

damage to look for:

  • cracked or broken cover
  • hydrometer
  • cracked or broken container
  • check terminal area for loose or broken parts.

Checking the hydrometer marine battery

The indicator is temperater-compensated hydrometer. In normal operation, one of two indication appears:

  • Green dot visable- battey is ready for load test. DO NOT CHARGE

Replace the battery if the dot apears to be clear, or light yellow and if a cranking complaint exists that is caused by the battery.

Dark no dot visible- recharge until green dot shows. shake or tilt battery to obtain green dot. A battery that has set in a completly discharged condition or is extremly cold may not accept current for serveral hours after starting the charger.


Once all the visual inspections, gravity check or hydrometer checking takes place doing a load test is important, as checking voltage only shows part of the situation. Testing the load should be preformed to access the entire situation accuratly. Most common way to conduct a load test is with a carbon pile load tester. Batteries can be tested inside or outside of the vehicle.

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