In the last article discharged and sulfated, or shorted, batteries were discussed. Another battery condition that will cause a vehicle not to start is an internally open battery. An internally open battery is not capable of recovering to a full charge, because of sections, or cells, inside the battery not functioning properly, or physically broken. Broken cells inside a battery are usually caused by a battery not being secured properly in the vehicle. A nonfunctioning, or dead cell in a battery is usually caused by excessive battery state of charge cycling, in other words, the battery has been completely discharged and recharged so many times that a cell may no longer function properly. The only repair for this type of battery condition is to replace the battery.
Batteries that are not secured properly are subject to movement, vibration, rattling, bouncing, etc. Under extreme conditions the battery could conceivably bounce high enough to allow both battery terminals to touch the underside of the hood at the same time causing sparks or arching. Excessive sparking or arching can cause an under hood fire. Another result of a battery not secured properly is a broken battery case or housing causing battery acid to leak out of the battery and contaminate or corrode other areas of the engine compartment.
The two most common methods of securing a battery are: two long, thin, hooked, threaded rods with nuts connected together with a cross bar, or a battery wedge block. The threaded rod method is generally used in older model vehicles. The wedge block method is used almost exclusively on newer model vehicles. When rods are used the rods are usually one quarter inch (1/4) or six millimeters (6mm) in diameter, but may also be, depending on the type of vehicle, five sixteenths (5/16) or eight millimeters (8mm) in diameter. Each rod has a hook on one end for attaching to holes in the battery tray. The tray is attached to the vehicle frame and is used to secure the battery. The opposite end of each rod is threaded so that the cross bar can be installed across the top of the battery and is held in place by regular nuts or wing nuts installed on the threaded ends of the rods. The rod type battery hold down can be purchased from your local Phoenix or Glendale, AZ. automotive parts stores such as NAPA, CarQuest, O’Reilly, or AutoZone.
The wedge method uses a hard molded plastic block that wedges the bottom edge of the battery under a ledge or flange of the battery tray. The block is held in place by a long bolt that goes through the block and secures or screws into the battery tray. The down side of this method is that the through bolt of the wedge is subject to battery acid corrosion and may be very difficult to remove. When installing a new through bolt the threads of the bolt should be coated with anti-seize compound. The battery wedge block and anti-seize compound are also available at your local Phoenix or Glendale, AZ. automotive parts stores such as NAPA, CarQuest, O’Reilly, or AutoZone.
In the next article, battery case distortion and replacement will be discussed.