Cummins/Onan — Battery Check (BT1)
Maintenance
From a Cummins/Onan service manual — check it applies to your exact model before use.
Applies to: Cummins/Onan HDKA, Cummins/Onan HDKAQ, Cummins/Onan HDKAR
Before you start
- Ignition of explosive battery gases can cause severe personal injury; keep ignition sources away.
Procedure
- Check battery charge condition with a hydrometer.
- Electrolyte specific gravity should be about 1.260 for a fully charged battery at 80 F (27 C).
- If not, add distilled water to keep electrolyte at proper level, then recharge the battery.
- If the battery will not recharge, replace it.
- If battery loses excess water, charge rate may be too high; if charge not maintained, rate may be too low.
Tools required
- Hydrometer Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Electrolyte specific gravity about 1.260 at 80 F (27 C)
Full service-parts list: Cummins/Onan HDKA →, Cummins/Onan HDKAQ →, Cummins/Onan HDKAR →
Source: Cummins/Onan service manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.