Battery Charging: Notes

Tools Required 

J 42000  Battery Tester

Fig 1: Hydrometer Readings

Courtesy of GENERAL MOTORS CORP.

• For best results, use an automatic taper-rate battery charger with a voltage capability of 16 volts.
• A battery showing a green dot in the hydrometer (1) does not need to be charged unless the J 42000  has shown that the battery needs to be charged.
• A battery showing a dark dot in the hydrometer (2) should be charged unless the J 42000  has indicated no charge is needed.
• Do not charge a battery when the built in hydrometer is clear or yellow in the center (3). Tap the hydrometer lightly in order to dislodge any air bubbles. The bubbles may cause a false indication. If the hydrometer is still clear or yellow, replace the battery.
• The charging area should be well ventilated.
• Do not charge a battery that appears to be frozen; allow the battery to warm to room temperature and test it before charging.