The following procedure should be used to recharge a very
low or completely discharged battery. Unless this procedure is properly followed,
   a perfectly good battery may be needlessly replaced.
Tools Required
J 39200  Digital Multimeter
- Measure the voltage at the battery terminal with a J 39200 
. If the battery voltage is below 11 VDC,
the charge current will be very low and it could take some time before  the
  battery accepts a current in excess of a few milliamperes. Such low current
   may not be detectable on some ammeters.
 
- Set the battery charger on a high setting.
 
- Some chargers feature polarity protection circuitry which prevents
charging unless the charger leads are connected to the battery terminals correctly.
   A completely discharged battery may not have enough voltage to activate
 this   circuitry, even though the leads are connected properly, making it
 appear that   the battery will not accept charging current. Therefore, follow
 the specific   charger manufacturer's instructions explaining how to bypass
 the polarity   protection circuitry, allowing the charger to charge a low-voltage
 battery.
 
- Battery chargers vary in the amount of voltage and current they
provide. The time required for a battery to accept measurable charger current
   at various voltages are as follows:
 
| •  | 16.0 VDC or more -- up to 4 hours | 
 
| •  | 14.0 to 15.9 VDC --  up to 8 hours | 
 
| •  | 13.9 VDC or less -- up to 16 hours | 
 
- If the charge current is still not measurable at the end of the
above charging times, the battery should be replaced.
 
- If the charge current is measurable during the charging time,
the battery is considered to be good and charging should be completed in the
   normal manner. Refer to 
Battery Charging 
.
 
- It is important to remember that a completely discharged battery
must be recharged for a sufficient number of ampere hours (AH) to restore
   it to a usable state. As a general rule, using the reserve capacity (RC)
  rating  of the battery as the number of ampere hours of charge will usually
  bring  the desired hydrometer indication (green dot) into view. The battery
  used  in this vehicle is rated at 50 RC minutes, therefore, it would be
completely    recharged as follows:
 
| •  | 10 ampere charge for 5 hours (10 x 5) = 50 AH | 
 
| •  | 25 ampere charge for 2 hours (25 x 2) = 50 AH | 
 
- Any battery recharged by this procedure should be load tested
to establish serviceability. Refer to 
Battery Load Test 
.