Frank's RV Electrical Information
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Testing Your Battery & Charging


What seams to be the problem?
  • Will not take a charge.
  • Runs down quickly.
  • Gets warm or hot when charging.
  • Makes a sound when charging.
Will not take a charge.
  • First make sure your charger or alternator working properly.
    ( And should be more than a half volt over the battery voltage.)
  • Make sure All the connections are good.
  • Note: If the battery is completly dead, it may take some time on the charger before it will except the charge.
  • Sometimes a dead battery will recover if it is placed on a long slow charge.
  • If the battery still dose not charge you may need to replace it.
Runs down quickly.
  • This could be from a poor charge or bad cell.
  • A good battery fully charged should read 12.6 volts. If you have just charged it leave it set a couple of hours before seeing if it is holding the charge.
  • Leave the battery disconnected for 24 hours, if it runs down it is bad.
  • Each bad cell will show up with about a 2.2 volt drop for each bad cell. ( 10.4 volts = 1 bad cell, 8.2 vlots = 2 bad cells etc.

Gets warm or hot when charging.
  • This could be from over charging with to larger of charger.
  • Bad cells can also cause a battery to over heat when being charged.
  • Another reason could be that the battery has sulfated. ( This happens when a battery sets dead, and it damages the plates in the battery.) You will most likely need to replace the battery.

Makes a sound when charging.
  • This to could be from an over charge or bad cell.
  • If you are not over charging with a high voltage, the battery is bad, and will most likely need replacement.

Load test the battery.
  • After charging your battery, put a load test on it, this is another good way to find out if the battery is good.

A good link for more battery information below.

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