I have a Generac Guardian 20kw air cooled standby generator. I recently replaced the battery charger as the battery went dead a few times over the last several months. Upon replacing the charger, I now have a red led indicator light and the unit will not crank. Alarm log does not identify the problem. The 7.5 amp fuse is good. Any Ideas?

Stormi Paulk

• 415 Answers
• Posted on Nov 07, 2010

SOURCE: battery does not stay charged on my 20kw generac

WAS A 110 VOLT CIRCUIT RAN TO IT FROM THE NORMAL UTILITY POWER OF HOME OR BUILDING IT FEEDS?
NORMALLY THIS IS DONE IN A SEPERATE CONDUIT FOR CONTROL WIRES.AND THE FEEDERS ARE IN ANOTHER CONDUIT.
WITH A DIGITAL TEST METER,CHECK FOR 120 VOLTS AT THE BATTERY CHARGER IN THE GENERATOR CABINET.USUALLY THERE IS A RECEPTICAL TO PLUG THE CHARGER INTO.
IF VOLTAGE IS PRESENT AT THE BATTERY CHARGER AND INDICATOR LIGHTS ARE ON, CHANGE METER TO DC AND CHECK FOR 13.8 VOLTS OUTPUT FROM THE BATTERY CHARGER.IF YOU HAVE OUTPUT VOLTAGE TO THE BATTERY,AND IT IS DEAD,CHANGE THE BATTERY..

HOPE THIS HELPS YOU,BEST OF LUCK.....

SOURCE: 2nd battery explosion with 3 year interval of flawless operation.

If the unit is using a wet cell acid battery, it's possible that dirt mixed with hydrogen build up on top of the battery caused the second failure. The battery top should be kept clean and should be checked at least 4 times per year. Any stray ignition source can cause the hydrogen to explode, including lightning.

It's also possible that the battery float charger needs to be adjusted or possibly has a problem. Some float chargers are adjustable. The higher the charging rate the more off-gassing the battery will experience and increase the chance of a failure.

If the battery has exploded, the entire generator and housing should be cleaned (washed) thoroughly to remove any remaining battery electrolyte (acid).

Be careful - if you aren't comfortable working on this type of equipment, it's best to call a local dealer and find a service vendor.