Things to know about Batteries


  1. Battery problems are the number 1 cause of road service calls.
  2. Battery efficiency decreases with falling temperatures. Engine cranking power demands increase with falling temperatures.
  3. A fast charge cannot fully re-charge a battery; follow up with a slow charge for 3 or 4 hours.
  4. A common, frequently unrecognized, cause of battery failure is overcharging.
  5. A hot battery charges (and also overcharges) faster than a cold one. A problem in hot weather during long trips.
  6. All batteries have a normal self-discharge rate that increases with temperature. Maintenance-free types have a substantially lower self-discharge rate.
  7. Store batteries in as cool a location as possible to minimize self-discharge.
  8. An old battery myth: A battery on a concrete floor discharges very rapidly. Not true; it will run down just as fast on any other surface.
  9. A heavy discharge will not damage the battery plates; overcharging, though, will.
  10. A fully charged battery freezes at –85 F. (50% charge at –15 F and 25% at +5 F)
  11. A battery left in a discharged state will “sulfate” and lose capacity.
  12. The only good battery is a fully charged battery.