Cummins/Onan — Battery Electrolyte Dilution for Hot Locations
Maintenance
From a Cummins/Onan operator's manual covering: 250DFT-57R8, 300DFT-4R8, 300DFT-4XR8, 300DFT-5DR8, 300DFT-6DR8, 300DFT-7XR8, 300DFT-9XR8. Check it applies to your exact model before use.
Browse Cummins/Onan generators & specs →
Before you start
- Avoid skin or clothing contact with electrolyte. Dispose safely.
Procedure
- Fully charge the battery.
- With battery still on charge, draw off electrolyte above plates in each cell using hydrometer or filler bulb.
- Refill each cell with distilled water to normal 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
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Specific gravity 1.275 at full charge; dilute to 1.225
- Charge rate 4-6 amperes
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.