Cummins/Onan — Batteries, Hot Location - Electrolyte Adjustment
Maintenance · Battery
From a Cummins/Onan service manual — check it applies to your exact model before use.
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Before you start
- Avoid skin or clothing contact with electrolyte; dispose safely.
Procedure
- Fully charge the battery.
- With battery on charge, draw off all electrolyte above plates in each cell using hydrometer or filler bulb. Do not pour off.
- Refill each cell with approved water to recommended level.
- Continue charging for 1 hour at 4 to 6 ampere rate.
- Test each cell. If specific gravity still above 1.225, repeat steps 2-4 until reading is 1.225.
Tools required
- hydrometer or filler bulb Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- specific gravity 1.225
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.