Cummins/Onan — Battery Electrolyte Dilution for High Temperature
Maintenance
From a Cummins/Onan operator's manual — check it applies to your exact model before use.
Applies to: Cummins/Onan EC series
Before you start
- Do not bring open flame or burning cigarette near battery during charging.
Procedure
- Fully charge battery.
- While on charge, draw off electrolyte above plates in each cell.
- Refill each cell with pure distilled water to recommended level.
- Continue charging one hour at 4 to 6 ampere rate.
- Test each cell with hydrometer; repeat steps 2-4 until fully charged reading is not over 1.225.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Normal 1.275 specific gravity
- Diluted 1.225 specific gravity
- 4 to 6 ampere charge rate
Source: Cummins/Onan operator's 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.