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Low battery voltage

Why generators show "low battery voltage": 6 documented causes and brand-specific fixes, compiled across 7 manufacturers.

1. Weak or discharged battery due to: a. Low charge rate. b. Low electrolyte level in battery. c. Long periods of non-use. d. Improperly wired battery.

1 brand
  • Orion: 1 a. Adjust slide tap on adjustable resistor R21 for proper charge rate. Refer to Battery Charge Rate Adjustment in Section 6. 1 b. Replenish electrolyte and recharge battery. 1 c. Connect a separate battery charger to bring battery up to full charge. 1 d. Reconnect and check battery connection.

No battery connected.<br>No output breaker is in the “Off” (down) position.<br>Charger is set for 24V charging with a 12V battery connected.<br>Battery can no longer maintain charge.<br>The wire between the charger and the battery is loose or broken.

1 brand
  • Cummins/Onan: Connect the battery.<br>Verify the output breaker is in “On” (up) position.<br>Attach a 24V battery or set the charger for 12V charging.<br>Replace the battery.<br>Check the wire.

A. Low charge rate.

1 brand
  • Onan: Adjust slide tap on adjustable resistor R21 for proper charge rate. Refer to Battery Charge - Rate Adjustment in Section 6.

No battery connected.; Output breaker is in the ‘Off’ (down) position.; A 12V battery is connected but the charger is set for 24V charging.; Battery can no longer maintain charge.; The wire between the charger and the battery is loose or broken.

1 brand
  • Cummins/Onan: Connect the battery.; Verify the output breaker is in ‘On’ (up) position.; Attach a 24V battery or set the charger for 12V charging.; Replace the battery.; Check the wire.

Weak or discharged battery due to: a. Low electrolyte level in battery.; b. Long periods of non-use.; c. Improperly wired battery.; d. Load connected to battery while set is turned off.; e. Too much DC load on genset starting battery.

1 brand
  • Cummins/Onan: Replenish electrolyte and recharge battery.; Connect a separate battery charger to bring battery up to full charge.; Reconnect and check battery connection.; Disconnect load and recharge battery.; Remove other DC loads from genset starting battery.

Faulty battery or battery charge circuit

1 brand
  • Briggs_Stratton: Remove the 15 Amp fuse and disconnect the battery from the generator. Take the battery to a local battery store for analysis. Or contact your local service center for assistance. Reinstall the battery (replace if necessary - see Battery in Final Installation Considerations in the installation manual). Then reset the fault detection system, as described earlier.

Common questions

What causes low battery voltage?

Common causes, most-reported first: 1. Weak or discharged battery due to: a. Low charge rate. b. Low electrolyte level in battery. c. Long periods of non-use. d. Improperly wired battery.; No battery connected.<br>No output breaker is in the “Off” (down) position.<br>Charger is set for 24V charging with a 12V battery connected.<br>Battery can no longer maintain charge.<br>The wire between the charger and the battery is loose or broken.; A. Low charge rate.; No battery connected.; Output breaker is in the ‘Off’ (down) position.; A 12V battery is connected but the charger is set for 24V charging.; Battery can no longer maintain charge.; The wire between the charger and the battery is loose or broken.; Weak or discharged battery due to: a. Low electrolyte level in battery.; b. Long periods of non-use.; c. Improperly wired battery.; d. Load connected to battery while set is turned off.; e. Too much DC load on genset starting battery.; Faulty battery or battery charge circuit.